/**
 * Copyright (C) 2014-2016 Triumph LLC
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
"use strict";

/**
 * Rendering graph routines.
 *
 * Rendering graph consists of rendering subscenes, which in turn may have
 * zero or more inputs and one or more outputs. All subscenes must be closed
 * to last SINK element. SINK element is a fictional subscene without any outputs.
 *
 * @name scenegraph
 * @namespace
 * @exports exports as scenegraph
 */
b4w.module["__scenegraph"] = function(exports, require) {

var m_cam    = require("__camera");
var m_cfg    = require("__config");
var m_debug  = require("__debug");
var m_graph  = require("__graph");
var m_render = require("__renderer");
var m_subs   = require("__subscene");
var m_tex    = require("__textures");
var m_util   = require("__util");

var cfg_dbg = m_cfg.debug_subs;
var cfg_def = m_cfg.defaults;
var cfg_scs = m_cfg.scenes;

var DEBUG_DISABLE_TEX_REUSE = false;

var LEFT_ONLY_SUBS_TYPES = [m_subs.GRASS_MAP, m_subs.SHADOW_CAST,
                            m_subs.MAIN_CUBE_REFLECT,
                            m_subs.MAIN_CUBE_REFLECT_BLEND];
/**
 * Enforce uniqueness
 */
function enforce_slink_uniqueness(graph, depth_tex) {
    var slinks = [];

    // make inter-subscene slinks unique
    m_graph.traverse_edges(graph, function(node1, node2, attr) {
        var slink = attr;

        if (slinks.indexOf(slink) > -1)
            m_graph.replace_edge_attr(graph, node1, node2, slink,
                    clone_slink(slink));
        else
            slinks.push(slink);
    });

    m_graph.traverse(graph, function(id, attr) {
        var subs = attr;

        // make internal slinks unique
        for (var i = 0; i < subs.slinks_internal.length; i++) {
            var slink = subs.slinks_internal[i];

            if (!depth_tex && (subs.type == m_subs.MAIN_PLANE_REFLECT ||
                    subs.type == m_subs.MAIN_CUBE_REFLECT ||
                    subs.type == m_subs.MAIN_XRAY))
                slink.use_renderbuffer = true;

            if (slinks.indexOf(slink) > -1)
                subs.slinks_internal[i] = clone_slink(slink);
            else
                slinks.push(slink);
        }
    });
}

/**
 * Slinks compliance, etc
 */
function enforce_graph_consistency(graph, depth_tex) {
    m_graph.traverse(graph, function(id, attr) {
        var subs = attr;

        // assign linear filtering to MOTION_BLUR accumulator
        // if such subscene connected to ANTIALIASING
        if (subs.type == m_subs.ANTIALIASING)
            m_graph.traverse_inputs(graph, id, function(id_in, attr_in,
                    attr_edge) {

                var subs_in = attr_in;

                if (subs_in.type == m_subs.MOTION_BLUR) {
                    for (var i = 0; i < subs_in.slinks_internal.length; i++) {
                        var slink_mb_int = subs_in.slinks_internal[i];
                        slink_mb_int.min_filter = m_tex.TF_LINEAR;
                        slink_mb_int.mag_filter = m_tex.TF_LINEAR;
                    }
                }
            });

        if (!depth_tex)
            m_graph.traverse_inputs(graph, id, function(id_in, attr_in,
                    attr_edge) {
                var subs = attr_in;
                var slink = attr_edge;

                if (slink.from == "DEPTH")
                    slink.use_renderbuffer = true;
            });
    });

    m_graph.traverse(graph, function(id, attr) {
        var subs = attr;

        var dest = {};

        combine_same_slinks(graph, id, dest);

        for (var i in dest) {
            var slinks = dest[i];

            // select maximum quality min filter
            var min_filt_slink = slinks[0];
            for (var j = 0; j < slinks.length; j++) {
                if (slinks[j].min_filter == m_tex.TF_LINEAR) {
                    min_filt_slink = slinks[j];
                    break;
                }
            }

            // select maximum quality mag filter
            var mag_filt_slink = slinks[0];
            for (var j = 0; j < slinks.length; j++) {
                if (slinks[j].mag_filter == m_tex.TF_LINEAR) {
                    mag_filt_slink = slinks[j];
                    break;
                }
            }

            // select non-renderbuffer
            var not_rb_slink = slinks[0];
            for (var j = 0; j < slinks.length; j++) {
                if (!slinks[j].use_renderbuffer) {
                    not_rb_slink = slinks[j];
                    break;
                }
            }

            // assign values from selected slinks
            for (var j = 0; j < slinks.length; j++) {
                slinks[j].min_filter = min_filt_slink.min_filter;
                slinks[j].mag_filter = mag_filt_slink.mag_filter;
                slinks[j].use_renderbuffer = not_rb_slink.use_renderbuffer;
            }
        }

    });
}

function combine_same_slinks(graph, id, dest) {

    m_graph.traverse_inputs(graph, id, function(id_in, attr_in,
            attr_edge) {
        var slink = attr_edge;

        // passive slink doesn't affect other
        if (!slink.active)
            return;

        if (slink.from == slink.to) {
            dest[slink.from] = dest[slink.from] || [];

            if (dest[slink.from].indexOf(slink) == -1)
                dest[slink.from].push(slink);

            combine_same_slinks(graph, id_in, dest);
        }
    });

    m_graph.traverse_outputs(graph, id, function(id_out, attr_out,
            attr_edge) {
        var slink = attr_edge;

        // passive slink doesn't affect other
        if (!slink.active)
            return;

        dest[slink.from] = dest[slink.from] || [];
        if (dest[slink.from].indexOf(slink) == -1)
            dest[slink.from].push(slink);
    });

    // special case: internal interchanges with output
    var subs = m_graph.get_node_attr(graph, id);
    if (subs.type == m_subs.MOTION_BLUR) {
        for (var i = 0; i < subs.slinks_internal.length; i++) {
            var slink = subs.slinks_internal[i];
            dest[slink.from].push(slink);
        }
    }
}


exports.check_slink_tex_conn = function(slink) {
    switch (slink.to) {
    case "COLOR":
    case "CUBEMAP":
    case "DEPTH":
    case "SCREEN":
    case "OFFSCREEN":
    case "RESOLVE":
    case "COPY":
    case "NONE":
        return false;
    default:
        return true;
    }
}

function process_subscene_links(graph) {
    // disable texture reuse for some scenes
    var FORCE_UNIQUE_TEXTURE_SUBS = [m_subs.MOTION_BLUR, m_subs.SMAA_RESOLVE,
            m_subs.SMAA_NEIGHBORHOOD_BLENDING, m_subs.MAIN_PLANE_REFLECT,
            m_subs.MAIN_CUBE_REFLECT, m_subs.PERFORMANCE];

    var graph_sorted = m_graph.topsort(graph);
    var tex_storage = [];

    m_graph.traverse(graph_sorted, function(id, attr) {
        var subs = attr;

        // assign new (or unused) internal textures
        for (var i = 0; i < subs.slinks_internal.length; i++) {
            var slink = subs.slinks_internal[i];

            if (FORCE_UNIQUE_TEXTURE_SUBS.indexOf(subs.type) > -1)
                slink.unique_texture = true;

            var tex = tex_aquire(tex_storage, slink,
                    calc_slink_id(slink));

            slink.texture = tex;
            subs.textures_internal[i] = tex;
        }

        // release internal textures now
        for (var i = 0; i < subs.textures_internal.length; i++) {
            var tex = subs.textures_internal[i];
            tex_dec_ref(tex_storage, tex);
        }

        // connect new (or unused) external textures
        m_graph.traverse_outputs(graph_sorted, id, function(id_out, attr_out,
                attr_edge) {
            var slink = attr_edge;

            if (FORCE_UNIQUE_TEXTURE_SUBS.indexOf(subs.type) > -1)
                slink.unique_texture = true;

            if (slink.texture)
                return;

            var tex = find_nearest_tex(graph_sorted, id, slink.from);
            if (tex && slink.active && !slink.texture) {
                tex_inc_ref(tex_storage, tex);
                slink.texture = tex;
                return;
            }

            var tex = tex_aquire(tex_storage, slink,
                    calc_slink_id(slink));

            slink.texture = tex;
        });

        // release unused textures from previous subscenes
        m_graph.traverse_inputs(graph_sorted, id, function(id_in, attr_in,
                attr_edge) {
            var slink = attr_edge;
            var subs_in = attr_in;

            tex_dec_ref(tex_storage, slink.texture);
        });

        // release unused non-connected textures
        m_graph.traverse_outputs(graph_sorted, id, function(id_out, attr_out,
                attr_edge) {
            var slink = attr_edge;

            if (slink.texture && slink.to == "NONE") {
                tex_dec_ref(tex_storage, slink.texture);
            }
        });
    });
}

function calc_slink_id(slink) {
    var id_obj = m_util.clone_object_json(slink);
    delete id_obj.to;
    delete id_obj.active;
    delete id_obj.texture;
    return JSON.stringify(id_obj);
}

function find_nearest_tex(graph, id, type) {

    var tex = null;

    m_graph.traverse_inputs(graph, id, function(id_in, attr_in,
            attr_edge) {
        var slink = attr_edge;

        if (slink.active && slink.from == slink.to && slink.from == type &&
                slink.texture) {
            tex = slink.texture;
            return true;
        }
    });

    m_graph.traverse_outputs(graph, id, function(id_out, attr_out,
            attr_edge) {
        var slink = attr_edge;

        if (slink.active && slink.from == type && slink.texture) {
            tex = slink.texture;
            return true;
        }
    });

    return tex;
}

function tex_inc_ref(storage, tex) {
    for (var i = 0; i < storage.length; i++) {
        var item = storage[i];

        if (item.tex === tex)
            item.ref++;
    }
}

function tex_dec_ref(storage, tex) {
    for (var i = 0; i < storage.length; i++) {
        var item = storage[i];

        if (item.tex === tex && item.ref)
            item.ref--;
    }
}

function tex_aquire(storage, slink, slink_id) {
    if (slink.parent_slink) {
        tex_inc_ref(storage, slink.parent_slink.texture);
        return slink.parent_slink.texture;
    }

    // a unique texture isn't presented in storage
    if (slink.unique_texture)
        return tex_create_for_slink(slink);

    var storage_item_free = null;

    // find first unused attachment
    for (var i = 0; i < storage.length; i++) {
        var item = storage[i];

        if (item.id == slink_id && item.ref === 0) {
            storage_item_free = item;
            break;
        }
    }

    if (storage_item_free && !(DEBUG_DISABLE_TEX_REUSE || cfg_def.firefox_tex_reuse_hack)) {
        storage_item_free.ref++;
        return storage_item_free.tex;
    } else {
        var tex = tex_create_for_slink(slink);
        storage.push({
            id: slink_id,
            ref: 1,
            tex: tex
        });
        return tex;
    }
}

function tex_create_for_slink(slink) {
    var size_x = slink.size_mult_x * slink.size;
    var size_y = slink.size_mult_y * slink.size;

    switch (slink.from) {
    case "COLOR":
        if (slink.use_renderbuffer) {
            var tex = m_tex.create_texture(slink.multisample ?
                    m_tex.TT_RB_RGBA_MS : m_tex.TT_RB_RGBA, slink.use_comparison);
            m_tex.resize(tex, size_x, size_y);
        } else {
            var tex = m_tex.create_texture(m_tex.TT_RGBA_INT,
                    slink.use_comparison);
            m_tex.resize(tex, size_x, size_y);
            m_tex.set_filters(tex, slink.min_filter, slink.mag_filter);
        }
        return tex;
    case "DEPTH":
        if (slink.use_renderbuffer) {
            var tex = m_tex.create_texture(slink.multisample ?
                    m_tex.TT_RB_DEPTH_MS : m_tex.TT_RB_DEPTH,
                    slink.use_comparison);
            m_tex.resize(tex, size_x, size_y);
        } else {
            var tex = m_tex.create_texture(m_tex.TT_DEPTH, slink.use_comparison);
            m_tex.resize(tex, size_x, size_y);
            m_tex.set_filters(tex, slink.min_filter, slink.mag_filter);
        }
        return tex;
    case "CUBEMAP":
        var tex = m_tex.create_cubemap_texture(size_x);
        return tex;
    case "SCREEN":
    case "NONE":
        return null;
    default:
        m_util.panic("Wrong slink param: " + slink.from);
    }
}

exports.traverse_slinks = traverse_slinks;
/**
 */
function traverse_slinks(graph, callback) {

    var exit = false;

    // process slinks assigned as inter-subscene edges
    m_graph.traverse_edges(graph, function(node1, node2, attr) {
        var slink = attr;
        if (!slink)
            return;

        var subs1 = m_graph.get_node_attr(graph, node1);
        var subs2 = m_graph.get_node_attr(graph, node2);

        if (callback(slink, false, subs1, subs2)) {
            exit = true;
            return true;
        }
    });

    if (exit)
        return;

    // process internal slinks
    m_graph.traverse(graph, function(node, attr) {
        var subs = attr;

        for (var i = 0; i < subs.slinks_internal.length; i++) {
            var slink = subs.slinks_internal[i];

            if (callback(slink, true, subs, null))
                return true;
        }
    });
}

function assign_render_targets(graph) {
    m_graph.traverse(graph, function(nid, subs) {
        if (subs.type == m_subs.SINK)
            return;

        var cam = subs.camera;
        m_graph.traverse_outputs(graph, nid, function(nid_out, subs_out,
                slink) {

            if (slink.active && slink.texture) {
                m_cam.set_attachment(cam, slink.from, slink.texture);

                if (slink.from == slink.to && subs_out.camera)
                    m_cam.set_attachment(subs_out.camera, slink.from, slink.texture);
            }
        });

        for (var i = 0; i < subs.slinks_internal.length; i++) {
            var slink = subs.slinks_internal[i];

            if (slink.active && slink.from == slink.to) {
                var tex = subs.textures_internal[i];
                m_cam.set_attachment(cam, slink.from, tex);
            }
        }

        if ((cam.color_attachment || cam.depth_attachment) && !cam.framebuffer)
            cam.framebuffer = m_render.render_target_create(cam.color_attachment,
                    cam.depth_attachment);
    });

    m_graph.traverse(graph, function(nid, subs) {
        if (subs.type == m_subs.RESOLVE || subs.type == m_subs.COPY) {
            var inputs = get_inputs(graph, subs);
            var cam = subs.camera;
            cam.framebuffer_prev = inputs[0].camera.framebuffer;
        }
    });
}

/**
 * Prepare full-featured rendering graph for given scene render.
 * @param {Object3D} sc_render Scene render object
 * @param {Object3D} cam_scene_data Camera scene data
 * @param {Object3D} cam_render Camera render object
 * @param {Boolean} render_to_textures Textures for offscreen rendering
 * @returns Rendering graph
 */
exports.create_rendering_graph = function(sc_render, cam_scene_data,
        cam_render, render_to_textures) {

    var graph = m_graph.create();

    // subscenes from previous level
    var prev_level = [];
    // currently populated level
    var curr_level = [];

    // shared
    var shadow_subscenes      = [];
    var shadow_links          = [];
    var reflect_subscenes     = [];
    var reflect_links         = [];
    var cube_refl_subscenes   = [];
    var cube_reflect_links    = [];

    var num_lights      = sc_render.lamps_number;
    var water_params    = sc_render.water_params;
    var shore_smoothing = sc_render.shore_smoothing;
    var soft_particles  = sc_render.soft_particles;
    var ssao            = sc_render.ssao;
    var god_rays        = sc_render.god_rays;
    var refl_params     = sc_render.reflection_params;
    var mat_params      = sc_render.materials_params;
    var bloom_params    = sc_render.bloom_params;
    var motion_blur     = sc_render.motion_blur;
    var compositing     = sc_render.compositing;
    var antialiasing    = sc_render.antialiasing;
    var wls_params      = sc_render.world_light_set;
    var wfs_params      = sc_render.world_fog_set;
    var shadow_params   = sc_render.shadow_params;
    var mb_params       = sc_render.mb_params;
    var cc_params       = sc_render.cc_params;
    var gr_params       = sc_render.god_rays_params;
    var outline_params  = sc_render.outline_params;
    var dof             = sc_render.dof;
    var depth_tex       = sc_render.depth_tex;
    var refractions     = sc_render.refractions;

    var rtt = Boolean(render_to_textures.length);
    var msaa = cfg_def.msaa_samples > 1;

    var slink_color_o = create_slink("COLOR", "COLOR", 1, 1, 1, true);
    var slink_depth_o = create_slink("DEPTH", "DEPTH", 1, 1, 1, true);
    if (msaa) {
        var slink_color_resolve_o = clone_slink(slink_depth_o);
        var slink_depth_resolve_o = clone_slink(slink_depth_o);
        slink_color_o.multisample = true;
        slink_color_o.use_renderbuffer = true;
        slink_depth_o.multisample = true;
        slink_depth_o.use_renderbuffer = true;
    }

    var main_cam = cam_scene_data.cameras[0];

    // shadow stuff
    if (shadow_params) {
        m_cam.update_camera_shadows(main_cam, shadow_params);

        for (var j = 0; j < shadow_params.lamp_types.length; j++) {
            var csm_num = shadow_params.csm_num;
            for (var i = 0; i < csm_num; i++) {
                var subs_shadow = m_subs.create_subs_shadow_cast(i, j, shadow_params, num_lights);
                m_graph.append_node_attr(graph, subs_shadow);
                shadow_subscenes.push(subs_shadow);

                var tex_size = shadow_params.csm_resolution;

                var cam = subs_shadow.camera;

                // NOTE: shadow cameras used in LOD shadows calculations
                cam_scene_data.shadow_cameras.push(cam);

                cam.width = tex_size;
                cam.height = tex_size;

                subs_shadow.clear_color = false;

                // NOTE: we use one lamp with csm or a lot of cast lamps
                var index = j > 0 ? j : i;

                var depth_slink = create_slink("DEPTH", "u_shadow_map" + index,
                            tex_size, 1, 1, false);
                if (cfg_def.compared_mode_depth) {
                    depth_slink.min_filter = m_tex.TF_LINEAR;
                    depth_slink.mag_filter = m_tex.TF_LINEAR;
                    depth_slink.use_comparison = true;
                }
                shadow_links.push(depth_slink);

                if (m_debug.check_depth_only_issue() || cfg_def.shadows_color_slink_hack) {
                    subs_shadow.slinks_internal.push(create_slink("COLOR",
                            "COLOR", tex_size, 1, 1, false));
                }
            }
        }
    }

    // cube reflections
    if (refl_params && refl_params.num_cube_refl && !rtt) {
        for (var i = 0; i < refl_params.num_cube_refl; i++) {
            var cam = m_cam.create_camera(m_cam.TYPE_PERSP);

            cam.width = sc_render.cubemap_refl_size;
            cam.height = sc_render.cubemap_refl_size;

            m_cam.set_frustum(cam, 90, 0.1, 100);
            m_cam.set_projection(cam, cam.aspect);

            var subs_refl = m_subs.create_subs_main(m_subs.MAIN_CUBE_REFLECT, cam, false,
                    water_params, num_lights, wfs_params, wls_params, null, sc_render.sun_exist);
            subs_refl.cube_view_matrices = m_util.generate_inv_cubemap_matrices();

            for (var j = 0; j < 6; j++)
                subs_refl.cube_cam_frustums.push(m_cam.create_frustum_planes());

            m_graph.append_node_attr(graph, subs_refl);

            var slink_refl_c = create_slink("CUBEMAP", "u_cube_reflection",
                                            sc_render.cubemap_refl_size, 1, 1, false);
            slink_refl_c.min_filter = m_tex.TF_LINEAR;
            slink_refl_c.mag_filter = m_tex.TF_LINEAR;

            cube_reflect_links.push(slink_refl_c);

            if (refl_params.has_blend_reflexible) {
                var subs_refl_blend = m_subs.create_subs_main(m_subs.MAIN_CUBE_REFLECT_BLEND, cam, false,
                        water_params, num_lights, wfs_params, wls_params, null, sc_render.sun_exist);
                subs_refl_blend.cube_view_matrices = subs_refl.cube_view_matrices;
                subs_refl_blend.cube_cam_frustums = subs_refl.cube_cam_frustums;

                m_graph.append_node_attr(graph, subs_refl_blend);
                var slink_depth_refl = create_slink("DEPTH", "DEPTH",
                                        sc_render.cubemap_refl_size, 1, 1, false);
                var slink_color_refl = create_slink("COLOR", "COLOR",
                                        sc_render.cubemap_refl_size, 1, 1, false);
                m_graph.append_edge_attr(graph, subs_refl, subs_refl_blend, slink_depth_refl);
                m_graph.append_edge_attr(graph, subs_refl, subs_refl_blend, slink_color_refl);

                cube_refl_subscenes.push(subs_refl_blend);
                refl_params.cube_refl_subs_blend.push(subs_refl_blend);
            } else {
                var slink_refl_d = create_slink("DEPTH", "DEPTH",
                                                sc_render.cubemap_refl_size, 1, 1, false);
                subs_refl.slinks_internal.push(slink_refl_d);
                cube_refl_subscenes.push(subs_refl);
            }
            refl_params.cube_refl_subs.push(subs_refl);
        }
    }

    // plane reflections
    if (refl_params && refl_params.refl_plane_objs.length > 0 && !rtt) {
        for (var j = 0; j < refl_params.refl_plane_objs.length; j++) {
            var cam = m_cam.clone_camera(main_cam, true);

            cam.reflection_plane = new Float32Array(4);
            cam_scene_data.cameras.push(cam);

            var subs_refl = m_subs.create_subs_main(m_subs.MAIN_PLANE_REFLECT, cam, false,
                               water_params, num_lights, wfs_params, wls_params,
                               null, sc_render.sun_exist);

            m_graph.append_node_attr(graph, subs_refl);

            var slink_refl_c = create_slink("COLOR", "u_plane_reflection", 1,
                                            sc_render.plane_refl_size,
                                            sc_render.plane_refl_size, true);
            slink_refl_c.min_filter = m_tex.TF_LINEAR;
            slink_refl_c.mag_filter = m_tex.TF_LINEAR;

            reflect_links.push(slink_refl_c);

            if (refl_params.has_blend_reflexible) {
                var subs_refl_blend = m_subs.create_subs_main(m_subs.MAIN_PLANE_REFLECT_BLEND,
                               cam, false, water_params, num_lights, wfs_params,
                               wls_params, null, sc_render.sun_exist);

                m_graph.append_node_attr(graph, subs_refl_blend);
                var slink_depth_refl = create_slink("DEPTH", "DEPTH", 1,
                                        sc_render.plane_refl_size,
                                        sc_render.plane_refl_size, true);
                var slink_color_refl = create_slink("COLOR", "COLOR", 1,
                                        sc_render.plane_refl_size,
                                        sc_render.plane_refl_size, true);
                slink_color_refl.min_filter = m_tex.TF_NEAREST;
                slink_color_refl.mag_filter = m_tex.TF_NEAREST;
                m_graph.append_edge_attr(graph, subs_refl, subs_refl_blend, slink_depth_refl);
                m_graph.append_edge_attr(graph, subs_refl, subs_refl_blend, slink_color_refl);

                refl_params.plane_refl_subs_blend.push([subs_refl_blend]);
                reflect_subscenes.push(subs_refl_blend);
            } else {
                var slink_refl_d = create_slink("DEPTH", "DEPTH", 1,
                                    sc_render.plane_refl_size,
                                    sc_render.plane_refl_size, true);

                subs_refl.slinks_internal.push(slink_refl_d);
                reflect_subscenes.push(subs_refl);
            }

            refl_params.plane_refl_subs.push([subs_refl]);
        }
    }

    // dynamic grass
    if (sc_render.dynamic_grass) {
        var subs_grass_map = m_subs.create_subs_grass_map();

        m_graph.append_node_attr(graph, subs_grass_map);

        var tex_size = cfg_scs.grass_tex_size;

        // NOTE: deprecated
        subs_grass_map.camera.width = tex_size;
        subs_grass_map.camera.height = tex_size;

        var slink_grass_map_d = create_slink("DEPTH", "u_grass_map_depth",
                tex_size, 1, 1, false);
        if (!cfg_def.webgl2) {
            slink_grass_map_d.min_filter = m_tex.TF_LINEAR;
            slink_grass_map_d.mag_filter = m_tex.TF_LINEAR;
        }

        // NOTE: need to be optional?
        var slink_grass_map_c = create_slink("COLOR", "u_grass_map_color",
                tex_size, 1, 1, false);
        slink_grass_map_c.min_filter = m_tex.TF_LINEAR;
        slink_grass_map_c.mag_filter = m_tex.TF_LINEAR;
    } else {
        var subs_grass_map = null;
        var slink_grass_map_d = null;
        var slink_grass_map_c = null;
    }

    // depth
    if (depth_tex && shadow_params) {
        var cam_sh_receive = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam_sh_receive);

        var subs_receive = m_subs.create_subs_shadow_receive(graph, cam_sh_receive, num_lights);

        m_graph.append_node_attr(graph, subs_receive);

        subs_receive.self_shadow_normal_offset = shadow_params.self_shadow_normal_offset;

        for (var i = 0; i < shadow_subscenes.length; i++) {
            var subs_shadow = shadow_subscenes[i];
            var slink_shadow = shadow_links[i];

            m_graph.append_edge_attr(graph, subs_shadow, subs_receive, slink_shadow);
        }

        var slink_depth_c = create_slink("COLOR", "u_color", 1, 1, 1, true);
        var slink_depth_d = create_slink("DEPTH", "u_depth", 1, 1, 1, true);

        if (ssao) {
            // ssao
            var cam_ssao = m_cam.clone_camera(main_cam, true);
            cam_scene_data.cameras.push(cam_ssao);

            var ssao_params = sc_render.ssao_params;
            var subs_ssao = m_subs.create_subs_ssao(cam_ssao, wfs_params, ssao_params);
            m_graph.append_node_attr(graph, subs_ssao);

            var slink_ssao = create_slink("COLOR", "u_ssao_mask", 1, 1, 1, true);

            m_graph.append_edge_attr(graph, subs_receive, subs_ssao, slink_depth_c);
            m_graph.append_edge_attr(graph, subs_receive, subs_ssao, slink_depth_d);

            // ssao_blur
            var cam_ssao_blur = m_cam.clone_camera(main_cam, true);
            cam_scene_data.cameras.push(cam_ssao_blur);

            var subs_ssao_blur = m_subs.create_subs_ssao_blur(cam_ssao_blur, ssao_params);
            m_graph.append_node_attr(graph, subs_ssao_blur);

            var slink_ssao_blur = create_slink("COLOR", "u_shadow_mask", 1, 1, 1, true);

            m_graph.append_edge_attr(graph, subs_ssao, subs_ssao_blur, slink_ssao);
            m_graph.append_edge_attr(graph, subs_receive, subs_ssao_blur, slink_depth_d);
        }

        if (msaa)
            subs_receive.slinks_internal.push(create_slink("DEPTH", "DEPTH", 1, 1, 1, true));
        else
            subs_receive.slinks_internal.push(slink_depth_o);

        if (subs_grass_map) {
            m_graph.append_edge_attr(graph, subs_grass_map, subs_receive,
                    slink_grass_map_d);
            m_graph.append_edge_attr(graph, subs_grass_map, subs_receive,
                    slink_grass_map_c);
        }
    } else
        var subs_receive = null;

    // main opaque
    var subs_main_opaque = m_subs.create_subs_main(m_subs.MAIN_OPAQUE, main_cam, true,
            water_params, num_lights, wfs_params, wls_params, null,
            sc_render.sun_exist);

    m_graph.append_node_attr(graph, subs_main_opaque);

    if (msaa) {
        var subs_res_opaque = m_subs.create_subs_resolve();
        m_graph.append_node_attr(graph, subs_res_opaque);

        curr_level.push(subs_res_opaque);

        var slink_resolve_in_c = create_slink("COLOR", "RESOLVE", 1, 1, 1, true);
        slink_resolve_in_c.multisample = true;
        slink_resolve_in_c.use_renderbuffer = true;
        var slink_resolve_in_d = create_slink("DEPTH", "RESOLVE", 1, 1, 1, true);
        slink_resolve_in_d.multisample = true;
        slink_resolve_in_d.use_renderbuffer = true;
        m_graph.append_edge_attr(graph, subs_main_opaque, subs_res_opaque, slink_resolve_in_c);
        m_graph.append_edge_attr(graph, subs_main_opaque, subs_res_opaque, slink_resolve_in_d);

        if (subs_receive) {
            if (slink_ssao)
                m_graph.append_edge_attr(graph, subs_ssao_blur, subs_main_opaque, slink_ssao_blur);
            else if (shadow_params)
                m_graph.append_edge_attr(graph, subs_receive, subs_main_opaque,
                    create_slink("COLOR", "u_shadow_mask", 1, 1, 1, true));
            else
                m_util.panic("Internal error");
        }
    } else {
        curr_level.push(subs_main_opaque);
        if (subs_receive) {
            if (slink_ssao)
                m_graph.append_edge_attr(graph, subs_ssao_blur, subs_main_opaque, slink_ssao_blur);
            else if (shadow_params)
                m_graph.append_edge_attr(graph, subs_receive, subs_main_opaque,
                    create_slink("COLOR", "u_shadow_mask", 1, 1, 1, true));
            else
                m_util.panic("Internal error");
        }
    }

    if (subs_grass_map) {
        m_graph.append_edge_attr(graph, subs_grass_map, subs_main_opaque,
                slink_grass_map_d);
        m_graph.append_edge_attr(graph, subs_grass_map, subs_main_opaque,
                slink_grass_map_c);
    }

    if (reflect_subscenes.length) {
        var num_refl_subs = reflect_subscenes.length;
        for (var j = 0; j < num_refl_subs; j++) {
            m_graph.append_edge_attr(graph,
                                     reflect_subscenes[j], subs_main_opaque,
                                     reflect_links[j]);
        }
    }

    if (cube_refl_subscenes.length) {
        for (var j = 0; j < cube_refl_subscenes.length; j++) {
            m_graph.append_edge_attr(graph, cube_refl_subscenes[j], subs_main_opaque,
                    cube_reflect_links[j]);
        }
    }

    prev_level = curr_level;
    curr_level = [];

    if (!rtt && sc_render.color_picking) {
        var cam = m_cam.clone_camera(main_cam, true);
        cam.width = 1;
        cam.height = 1;

        // camera depends on bpy camera
        cam_scene_data.cameras.push(cam);

        var subs_color_picking = m_subs.create_subs_color_picking(cam, false, num_lights);
        m_graph.append_node_attr(graph, subs_color_picking);

        if (sc_render.xray) {
            var cam = m_cam.clone_camera(main_cam, true);
            cam.width = 1;
            cam.height = 1;

            cam_scene_data.cameras.push(cam);
            var subs_color_picking_xray = m_subs.create_subs_color_picking(cam, true, num_lights);
            m_graph.append_node_attr(graph, subs_color_picking_xray);
            var cp_slink_c = create_slink("COLOR", "COLOR", 1, 1, 1, false);
            m_graph.append_edge_attr(graph, subs_color_picking,
                                     subs_color_picking_xray, cp_slink_c);
            var cp_slink_d = create_slink("DEPTH", "DEPTH", 1, 1, 1, false);
            m_graph.append_edge_attr(graph, subs_color_picking,
                                     subs_color_picking_xray, cp_slink_d);
        }
    } else
        var subs_color_picking = null;

    // refraction subscene
    if ((mat_params.refractions || refractions) && !rtt) {
        if (!msaa) {
            var subs_refr = m_subs.create_subs_copy();
            m_graph.append_node_attr(graph, subs_refr);

            var slink_refr_in = create_slink("COLOR", "COPY", 1, 1, 1, true);
            m_graph.append_edge_attr(graph, prev_level[0], subs_refr, slink_refr_in);
        } else
            var subs_refr = subs_res_opaque;

        var slink_refr = create_slink("COLOR", "u_refractmap", 1, 1, 1, true);
    } else
        var subs_refr = null;

    if (depth_tex && (refractions || shore_smoothing || soft_particles)) {

        var cam_depth_pack = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam_depth_pack);

        var subs_depth_pack = m_subs.create_subs_depth_pack(cam_depth_pack);
        m_graph.append_node_attr(graph, subs_depth_pack);

        var slink_depth_pack_in = create_slink("DEPTH", "u_depth", 1, 1, 1, true);
        m_graph.append_edge_attr(graph, msaa ? subs_res_opaque : subs_main_opaque,
                subs_depth_pack, slink_depth_pack_in);

        var slink_depth_pack_out = create_slink("COLOR", "u_scene_depth", 1, 1, 1, true);
        // disable filtering for packed depth
        slink_depth_pack_out.min_filter = m_tex.TF_NEAREST;
        slink_depth_pack_out.mag_filter = m_tex.TF_NEAREST;
    } else
        var subs_depth_pack = null;

    // to prevent code duplication
    var create_custom_sub_main = function(type) {
        var cam = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam);

        var subs_main = m_subs.create_subs_main(type, cam, false, water_params,
                num_lights, wfs_params, wls_params, shadow_params, sc_render.sun_exist);

        m_graph.append_node_attr(graph, subs_main);

        if (type == m_subs.MAIN_XRAY) {
            // NOTE: disable MSAA
            var slink_color = create_slink("COLOR", "COLOR", 1, 1, 1, true);
            m_graph.append_edge_attr(graph, prev_level[0], subs_main, slink_color);

            var slink_depth = create_slink("DEPTH", "DEPTH", 1, 1, 1, true);
            subs_main.slinks_internal.push(slink_depth);
        } else {
            // NOTE: it's possible to do better
            if (msaa && prev_level[0].type == m_subs.RESOLVE)
                var subs_prev = subs_main_opaque;
            else
                var subs_prev = prev_level[0];

            m_graph.append_edge_attr(graph, subs_prev, subs_main,
                                     slink_depth_o);
            m_graph.append_edge_attr(graph, subs_prev, subs_main, slink_color_o);
        }

        if (subs_grass_map) {
            m_graph.append_edge_attr(graph, subs_grass_map, subs_main,
                    slink_grass_map_d);
            m_graph.append_edge_attr(graph, subs_grass_map, subs_main,
                    slink_grass_map_c);
        }

        for (var i = 0; i < shadow_subscenes.length; i++) {
            var subs_shadow = shadow_subscenes[i];
            var slink_shadow = shadow_links[i];

            m_graph.append_edge_attr(graph, subs_shadow, subs_main, slink_shadow);
        }

        if (subs_depth_pack)
            m_graph.append_edge_attr(graph, subs_depth_pack, subs_main,
                    slink_depth_pack_out);

        if (reflect_subscenes.length) {
            var num_refl_subs = reflect_subscenes.length;
            for (var i = 0; i < num_refl_subs; i++)
                m_graph.append_edge_attr(graph, reflect_subscenes[i],
                        subs_main, reflect_links[i]);
        }
        if (cube_refl_subscenes.length) {
            for (var i = 0; i < cube_refl_subscenes.length; i++) {
                m_graph.append_edge_attr(graph, cube_refl_subscenes[i], subs_main,
                        cube_reflect_links[i]);
            }
        }

        if (subs_refr)
            m_graph.append_edge_attr(graph, subs_refr, subs_main, slink_refr);

        return subs_main;
    }

    if (sc_render.glow_over_blend) {
        var subs_main_blend = create_custom_sub_main(m_subs.MAIN_BLEND)
        curr_level.push(subs_main_blend);

        prev_level = curr_level;
        curr_level = [];
    }

    // main glow
    if (sc_render.glow_materials) {
        var cam_glow = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam_glow);

        var subs_main_glow = m_subs.create_subs_main(m_subs.MAIN_GLOW, cam_glow, false, water_params,
                num_lights, wfs_params, wls_params);
        m_graph.append_node_attr(graph, subs_main_glow);

        // link some uniforms likewise for the MAIN_OPAQUE subscene
        if (subs_depth_pack)
            m_graph.append_edge_attr(graph, subs_depth_pack, subs_main_glow,
                    slink_depth_pack_out);
        if (subs_refr)
            m_graph.append_edge_attr(graph, subs_refr, subs_main_glow, slink_refr);

        if (subs_grass_map) {
            m_graph.append_edge_attr(graph, subs_grass_map, subs_main_glow,
                    slink_grass_map_d);
            m_graph.append_edge_attr(graph, subs_grass_map, subs_main_glow,
                    slink_grass_map_c);
        }

        if (reflect_subscenes.length) {
            var num_refl_subs = reflect_subscenes.length;
            for (var j = 0; j < num_refl_subs; j++) {
                m_graph.append_edge_attr(graph,
                                         reflect_subscenes[j], subs_main_glow,
                                         reflect_links[j]);
            }
        }

        if (cube_refl_subscenes.length) {
            for (var j = 0; j < cube_refl_subscenes.length; j++) {
                m_graph.append_edge_attr(graph, cube_refl_subscenes[j], subs_main_glow,
                        cube_reflect_links[j]);
            }
        }

        m_graph.append_edge_attr(graph, msaa ? subs_res_opaque : subs_main_opaque,
                subs_main_glow, msaa ? slink_depth_resolve_o : slink_depth_o);
        var blur_x = m_subs.create_subs_postprocessing("X_GLOW_BLUR");
        blur_x.subtype = "GLOW_MASK_SMALL";
        set_texel_size_mult(blur_x, sc_render.glow_params.small_glow_mask_width);
        var slink_blur_x = create_slink("COLOR", "u_color", 1, 1, 1, true);
        slink_blur_x.min_filter = m_tex.TF_LINEAR;
        slink_blur_x.mag_filter = m_tex.TF_LINEAR;
        m_graph.append_node_attr(graph, blur_x);
        m_graph.append_edge_attr(graph, subs_main_glow, blur_x, slink_blur_x);

        var blur_y = m_subs.create_subs_postprocessing("Y_GLOW_BLUR");
        blur_y.subtype = "GLOW_MASK_SMALL";
        set_texel_size_mult(blur_y, sc_render.glow_params.small_glow_mask_width);
        var slink_blur_y = create_slink("COLOR", "u_color", 1, 0.5, 0.5, true);
        slink_blur_y.min_filter = m_tex.TF_LINEAR;
        slink_blur_y.mag_filter = m_tex.TF_LINEAR;
        m_graph.append_node_attr(graph, blur_y);
        m_graph.append_edge_attr(graph, blur_x, blur_y, slink_blur_y);

        var blur_x2 = m_subs.create_subs_postprocessing("X_GLOW_BLUR");
        blur_x2.subtype = "GLOW_MASK_LARGE";
        set_texel_size_mult(blur_x2, sc_render.glow_params.large_glow_mask_width);
        var slink_blur_x2 = create_slink("COLOR", "u_color", 1, 0.5, 0.5, true);
        slink_blur_x2.min_filter = m_tex.TF_LINEAR;
        slink_blur_x2.mag_filter = m_tex.TF_LINEAR;
        m_graph.append_node_attr(graph, blur_x2);
        m_graph.append_edge_attr(graph, blur_y, blur_x2, slink_blur_x2);

        var blur_y2 = m_subs.create_subs_postprocessing("Y_GLOW_BLUR");
        blur_y2.subtype = "GLOW_MASK_LARGE";
        set_texel_size_mult(blur_y2, sc_render.glow_params.large_glow_mask_width);
        var slink_blur_y2 = create_slink("COLOR", "u_color", 1, 0.25, 0.25, true);
        slink_blur_y2.min_filter = m_tex.TF_LINEAR;
        slink_blur_y2.mag_filter = m_tex.TF_LINEAR;
        m_graph.append_node_attr(graph, blur_y2);
        m_graph.append_edge_attr(graph, blur_x2, blur_y2, slink_blur_y2);

        var cam_glow_combine = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam_glow_combine);
        var subs_glow_combine = m_subs.create_subs_glow_combine(cam_glow_combine, sc_render);

        m_graph.append_node_attr(graph, subs_glow_combine);

        var slink_c_src = create_slink("COLOR", "u_src_color", 1, 1, 1, true);

        if (sc_render.glow_over_blend) {
            if (msaa) {
                // NOTE: redundant resolve, place the scene below debug_view or so
                var subs_res_blend = m_subs.create_subs_resolve();
                m_graph.append_node_attr(graph, subs_res_blend);

                m_graph.append_edge_attr(graph, subs_main_blend, subs_res_blend,
                        slink_resolve_in_c);
                m_graph.append_edge_attr(graph, subs_main_blend, subs_res_blend,
                        slink_resolve_in_d);
                m_graph.append_edge_attr(graph, subs_res_blend, subs_glow_combine, slink_c_src);
            } else
                m_graph.append_edge_attr(graph, subs_main_blend,
                        subs_glow_combine, slink_c_src);
        } else
            m_graph.append_edge_attr(graph, msaa ? subs_res_opaque : subs_main_opaque,
                    subs_glow_combine, slink_c_src);

        // not needed for combine postprocessing but simplifies keeping graph integrity
        // so it's always possible to get DEPTH-DEPTH link from it
        var subs_depth_in = sc_render.glow_over_blend ? subs_main_blend : subs_main_opaque;
        m_graph.append_edge_attr(graph, subs_depth_in, subs_glow_combine, slink_depth_o);

        var slink_c_y = create_slink("COLOR", "u_glow_mask_small", 1, 0.5, 0.5, true);
        slink_c_y.min_filter = m_tex.TF_LINEAR;
        slink_c_y.mag_filter = m_tex.TF_LINEAR;
        m_graph.append_edge_attr(graph, blur_y, subs_glow_combine, slink_c_y);

        var slink_c_y2 = create_slink("COLOR", "u_glow_mask_large", 1, 0.25, 0.25, true);
        slink_c_y2.min_filter = m_tex.TF_LINEAR;
        slink_c_y2.mag_filter = m_tex.TF_LINEAR;
        m_graph.append_edge_attr(graph, blur_y2, subs_glow_combine, slink_c_y2);

        prev_level = [subs_glow_combine];
        curr_level = [];
    }

    if (!sc_render.glow_over_blend) {
        var subs_main_blend = create_custom_sub_main(m_subs.MAIN_BLEND);
        curr_level.push(subs_main_blend);

        prev_level = curr_level;
        curr_level = [];
    }

    // debug view stuff: wireframe, clustering
    if (cfg_def.debug_view) {
        var cam = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam);

        var subs_debug_view = m_subs.create_subs_debug_view(cam);
        curr_level.push(subs_debug_view);
        m_graph.append_node_attr(graph, subs_debug_view);
        m_graph.append_edge_attr(graph, prev_level[0], subs_debug_view,
                slink_color_o);
        m_graph.append_edge_attr(graph, prev_level[0], subs_debug_view,
                slink_depth_o);

        if (subs_grass_map) {
            m_graph.append_edge_attr(graph, subs_grass_map, subs_debug_view,
                    slink_grass_map_d);
            m_graph.append_edge_attr(graph, subs_grass_map, subs_debug_view,
                    slink_grass_map_c);
        }

        m_debug.set_debug_view_subs(subs_debug_view);

        prev_level = curr_level;
        curr_level = [];
    }

    if (msaa) {
        var subs_res_geom = m_subs.create_subs_resolve();
        m_graph.append_node_attr(graph, subs_res_geom);
        curr_level.push(subs_res_geom);

        m_graph.append_edge_attr(graph, prev_level[0], subs_res_geom, slink_resolve_in_c);
        m_graph.append_edge_attr(graph, prev_level[0], subs_res_geom, slink_resolve_in_d);

        prev_level = curr_level;
        curr_level = [];
    }

    // last level of geometry rendering
    var last_geom_level = prev_level.slice(0);

    // prepare anchor visibility subscene
    if (!rtt && sc_render.anchor_visibility) {
        var cam = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam);

        // NOTE: possible bugs due to texture reuse
        var subs_anchor = m_subs.create_subs_anchor_visibility(cam);
        m_graph.append_node_attr(graph, subs_anchor);

        m_graph.append_edge_attr(graph, prev_level[0], subs_anchor,
                msaa ? slink_depth_resolve_o : slink_depth_o);
    }

    // god rays stuff
    if (god_rays && depth_tex && !rtt) {
        var max_ray_length = gr_params.max_ray_length;
        var intensity      = gr_params.intensity;
        var steps_per_pass = gr_params.steps_per_pass;

        var subs_prev = prev_level[0];
        var water = water_params ? true : false;

        var slink_gr_d = create_slink("DEPTH", "u_input", 1, 1, 1, true);
        var slink_gr_c = create_slink("COLOR", "u_input", 1, 0.25, 0.25, true);
        slink_gr_c.min_filter = m_tex.TF_LINEAR;
        slink_gr_c.mag_filter = m_tex.TF_LINEAR;

        // 1-st pass
        var step = max_ray_length / steps_per_pass;
        var cam_god_rays = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam_god_rays);
        var subs_god_rays = m_subs.create_subs_god_rays(cam_god_rays,
                            water, max_ray_length, true, step, num_lights,
                            steps_per_pass);
        m_graph.append_node_attr(graph, subs_god_rays);
        m_graph.append_edge_attr(graph, subs_prev, subs_god_rays, slink_gr_d);

        // 2-nd pass
        step = max_ray_length / steps_per_pass * 0.5;
        var cam_blur1 = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam_blur1);
        var subs_gr_blur1 = m_subs.create_subs_god_rays(cam_blur1,
                            water, max_ray_length, false, step, num_lights,
                            steps_per_pass);
        m_graph.append_node_attr(graph, subs_gr_blur1);
        m_graph.append_edge_attr(graph, subs_god_rays, subs_gr_blur1, slink_gr_c);

        // 3-d pass
        step = max_ray_length / steps_per_pass * 0.25;
        var cam_blur2 = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam_blur2);
        var subs_gr_blur2 = m_subs.create_subs_god_rays(cam_blur2,
                            water, max_ray_length, false, step, num_lights,
                            steps_per_pass);
        m_graph.append_node_attr(graph, subs_gr_blur2);
        m_graph.append_edge_attr(graph, subs_gr_blur1, subs_gr_blur2, slink_gr_c);

        // combine with main scene
        var subs_god_rays_comb = m_subs.create_subs_god_rays_comb(intensity,
                                                           num_lights);
        curr_level.push(subs_god_rays_comb);
        m_graph.append_node_attr(graph, subs_god_rays_comb);
        m_graph.append_edge_attr(graph, subs_prev, subs_god_rays_comb,
                create_slink("COLOR", "u_main", 1, 1, 1, true));
        m_graph.append_edge_attr(graph, subs_gr_blur2, subs_god_rays_comb,
                create_slink("COLOR", "u_god_rays", 1, 1, 1, true));

        prev_level = curr_level;
        curr_level = [];
    }

    // bloom
    if (bloom_params && !rtt) {
        var subs_prev = prev_level[0];

        var subs_luminance = m_subs.create_subs_luminance();
        m_graph.append_node_attr(graph, subs_luminance);
        m_graph.append_edge_attr(graph, subs_prev, subs_luminance,
                create_slink("COLOR", "u_input", 1, 1, 1, true));

        var subs_av_luminance = m_subs.create_subs_av_luminance();
        m_graph.append_node_attr(graph, subs_av_luminance);

        // NOTE: deprecated
        subs_av_luminance.camera.width = cfg_def.edge_min_tex_size_hack? 2: 1;
        subs_av_luminance.camera.height = cfg_def.edge_min_tex_size_hack? 2: 1;

        var slink_luminance_av = create_slink("COLOR", "u_input", 1, 0.25, 0.25, true);
        slink_luminance_av.min_filter = m_tex.TF_LINEAR;
        slink_luminance_av.mag_filter = m_tex.TF_LINEAR;

        var slink_luminance_tr = create_slink("COLOR", "u_luminance", 1, 0.25, 0.25, true);
        slink_luminance_tr.min_filter = m_tex.TF_LINEAR;
        slink_luminance_tr.mag_filter = m_tex.TF_LINEAR;

        m_graph.append_edge_attr(graph, subs_luminance, subs_av_luminance,
                slink_luminance_av);

        var bloom_key = bloom_params.key;
        var edge_lum  = bloom_params.edge_lum;

        var cam_luminance = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam_luminance);
        var subs_lum_trunced = m_subs.create_subs_luminance_trunced(bloom_key,
                                     edge_lum, num_lights, cam_luminance);

        m_graph.append_node_attr(graph, subs_lum_trunced);
        m_graph.append_edge_attr(graph, subs_prev, subs_lum_trunced,
                create_slink("COLOR", "u_main", 1, 1, 1, true));
        m_graph.append_edge_attr(graph, subs_luminance, subs_lum_trunced,
                slink_luminance_tr);
        m_graph.append_edge_attr(graph, subs_av_luminance, subs_lum_trunced,
                create_slink("COLOR", "u_average_lum", 1, 1, 1, false));

        var slink_blur_in = create_slink("COLOR", "u_color", 1, 0.25, 0.25, true);
        slink_blur_in.min_filter = m_tex.TF_LINEAR;
        slink_blur_in.mag_filter = m_tex.TF_LINEAR;

        var blur_x = m_subs.create_subs_bloom_blur(graph, subs_luminance, "X_BLUR", true);
        m_graph.append_node_attr(graph, blur_x);
        m_graph.append_edge_attr(graph, subs_lum_trunced, blur_x, slink_blur_in);

        var blur_y = m_subs.create_subs_bloom_blur(graph, blur_x, "Y_BLUR", true);
        m_graph.append_node_attr(graph, blur_y);
        m_graph.append_edge_attr(graph, blur_x, blur_y, slink_blur_in);

        var bloom_blur = bloom_params.blur;
        var subs_bloom_combine = m_subs.create_subs_bloom_combine(bloom_blur);
        m_graph.append_node_attr(graph, subs_bloom_combine);

        var slink_bloom = create_slink("COLOR", "u_bloom", 1, 0.25, 0.25, true);
        slink_bloom.min_filter = m_tex.TF_LINEAR;
        slink_bloom.mag_filter = m_tex.TF_LINEAR;
        m_graph.append_edge_attr(graph, blur_y, subs_bloom_combine, slink_bloom);
        m_graph.append_edge_attr(graph, subs_prev, subs_bloom_combine,
                create_slink("COLOR", "u_main", 1, 1, 1, true));

        curr_level.push(subs_bloom_combine);
        prev_level = curr_level;
        curr_level = [];
    }

    // depth of field stuff
    if (dof && depth_tex && !rtt) {
        var subs_prev = prev_level[0];
        var cam_dof = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam_dof);

        if (cam_render.dof_bokeh) {
            var slink_coc_in = create_slink("COLOR", "u_color", 1, 1, 1, true);
            slink_coc_in.min_filter = m_tex.TF_LINEAR;
            slink_coc_in.mag_filter = m_tex.TF_LINEAR;

            var slink_coc_depth_in = create_slink("DEPTH", "u_depth", 1, 1, 1, true)

            var slink_coc_out = create_slink("COLOR", "u_color", 1, 0.5, 0.5, true);
            slink_coc_out.min_filter = m_tex.TF_NEAREST;
            slink_coc_out.mag_filter = m_tex.TF_NEAREST;

            var slink_blur_in = create_slink("COLOR", "u_color", 1, 0.5, 0.5, true);
            slink_blur_in.min_filter = m_tex.TF_NEAREST;
            slink_blur_in.mag_filter = m_tex.TF_NEAREST;

            var slink_dof_blurred_in1 = create_slink("COLOR", "u_blurred1", 1, 0.5, 0.5, true)
            slink_dof_blurred_in1.min_filter = m_tex.TF_LINEAR;
            slink_dof_blurred_in1.mag_filter = m_tex.TF_LINEAR;

            var slink_dof_blurred_in2 = create_slink("COLOR", "u_blurred2", 1, 0.5, 0.5, true)
            slink_dof_blurred_in2.min_filter = m_tex.TF_LINEAR;
            slink_dof_blurred_in2.mag_filter = m_tex.TF_LINEAR;

            var subs_coc_in = last_geom_level[0];
            if (cam_render.dof_foreground_blur) {
                var cam_coc_fg = m_cam.clone_camera(main_cam, true);
                    cam_scene_data.cameras.push(cam_coc_fg);
                var coc_fg = m_subs.create_subs_coc(cam_coc_fg, "COC_FOREGROUND");
                cam_coc_fg.dof_distance = cam_render.dof_distance;
                cam_coc_fg.dof_object = cam_render.dof_object;
                cam_coc_fg.dof_front_start = cam_render.dof_front_start;
                cam_coc_fg.dof_front_end = cam_render.dof_front_end;
                cam_coc_fg.dof_rear_start = cam_render.dof_rear_start;
                cam_coc_fg.dof_rear_end = cam_render.dof_rear_end;
                cam_coc_fg.dof_power = cam_render.dof_power;
                cam_coc_fg.dof_bokeh = cam_render.dof_bokeh;
                cam_coc_fg.dof_bokeh_intensity = cam_render.dof_bokeh_intensity;
                cam_coc_fg.dof_foreground_blur = cam_render.dof_foreground_blur;
                cam_coc_fg.dof_on = true;
                m_graph.append_node_attr(graph, coc_fg);
                m_graph.append_edge_attr(graph, subs_prev, coc_fg, slink_coc_in);
                m_graph.append_edge_attr(graph, subs_coc_in, coc_fg, slink_coc_depth_in);

                var pp_alpha_x = m_subs.create_subs_postprocessing("X_ALPHA_BLUR");
                m_graph.append_node_attr(graph, pp_alpha_x);
                m_graph.append_edge_attr(graph, coc_fg, pp_alpha_x, slink_coc_out);

                var pp_alpha_y = m_subs.create_subs_postprocessing("Y_ALPHA_BLUR");
                m_graph.append_node_attr(graph, pp_alpha_y);
                m_graph.append_edge_attr(graph, pp_alpha_x, pp_alpha_y, slink_blur_in);

                var cam_coc = m_cam.clone_camera(main_cam, true);
                var coc = m_subs.create_subs_coc(cam_coc, "COC_COMBINE");
                cam_scene_data.cameras.push(cam_coc);
                cam_coc.dof_distance = cam_render.dof_distance;
                cam_coc.dof_object = cam_render.dof_object;
                cam_coc.dof_front_start = cam_render.dof_front_start;
                cam_coc.dof_front_end = cam_render.dof_front_end;
                cam_coc.dof_rear_start = cam_render.dof_rear_start;
                cam_coc.dof_rear_end = cam_render.dof_rear_end;
                cam_coc.dof_power = cam_render.dof_power;
                cam_coc.dof_bokeh = cam_render.dof_bokeh;
                cam_coc.dof_bokeh_intensity = cam_render.dof_bokeh_intensity;
                cam_coc.dof_foreground_blur = cam_render.dof_foreground_blur;
                cam_coc.dof_on = true;
                m_graph.append_node_attr(graph, coc);
                m_graph.append_edge_attr(graph, subs_prev, coc, slink_coc_in);
                m_graph.append_edge_attr(graph, subs_coc_in, coc, slink_coc_depth_in);
                m_graph.append_edge_attr(graph, pp_alpha_y, coc,
                    create_slink("COLOR", "u_coc_fg", 1, 0.5, 0.5, true));
            } else {
                var cam_coc = m_cam.clone_camera(main_cam, true);
                cam_scene_data.cameras.push(cam_coc);
                var coc = m_subs.create_subs_coc(cam_coc, "COC_ALL");
                cam_coc.dof_distance = cam_render.dof_distance;
                cam_coc.dof_object = cam_render.dof_object;
                cam_coc.dof_front_start = cam_render.dof_front_start;
                cam_coc.dof_front_end = cam_render.dof_front_end;
                cam_coc.dof_rear_start = cam_render.dof_rear_start;
                cam_coc.dof_rear_end = cam_render.dof_rear_end;
                cam_coc.dof_power = cam_render.dof_power;
                cam_coc.dof_bokeh = cam_render.dof_bokeh;
                cam_coc.dof_bokeh_intensity = cam_render.dof_bokeh_intensity;
                cam_coc.dof_foreground_blur = cam_render.dof_foreground_blur;
                cam_coc.dof_on = true;
                m_graph.append_node_attr(graph, coc);
                m_graph.append_edge_attr(graph, subs_prev, coc, slink_coc_in);
                m_graph.append_edge_attr(graph, subs_coc_in, coc, slink_coc_depth_in);
            }

            var pp_x = m_subs.create_subs_postprocessing("X_DOF_BLUR");
            pp_x.camera.dof_bokeh_intensity = cam_render.dof_bokeh_intensity;
            m_graph.append_node_attr(graph, pp_x);
            m_graph.append_edge_attr(graph, coc, pp_x, slink_coc_out);

            var pp_y1 = m_subs.create_subs_postprocessing("Y_DOF_BLUR");
            pp_y1.camera.dof_bokeh_intensity = cam_render.dof_bokeh_intensity;
            m_graph.append_node_attr(graph, pp_y1);
            m_graph.append_edge_attr(graph, pp_x, pp_y1, slink_blur_in);

            var pp_y2 = m_subs.create_subs_postprocessing("Y_DOF_BLUR");
            pp_y2.camera.dof_bokeh_intensity = cam_render.dof_bokeh_intensity;
            m_graph.append_node_attr(graph, pp_y2);
            m_graph.append_edge_attr(graph, pp_x, pp_y2, slink_blur_in);

            var subs_dof = m_subs.create_subs_dof(cam_dof);
            cam_dof.dof_distance = cam_render.dof_distance;
            cam_dof.dof_object = cam_render.dof_object;
            cam_dof.dof_front_start = cam_render.dof_front_start;
            cam_dof.dof_front_end = cam_render.dof_front_end;
            cam_dof.dof_rear_start = cam_render.dof_rear_start;
            cam_dof.dof_rear_end = cam_render.dof_rear_end;
            cam_dof.dof_power = cam_render.dof_power;
            cam_dof.dof_bokeh = cam_render.dof_bokeh;
            cam_dof.dof_bokeh_intensity = cam_render.dof_bokeh_intensity;
            cam_dof.dof_foreground_blur = cam_render.dof_foreground_blur;
            cam_dof.dof_on = true;
            curr_level.push(subs_dof);

            m_graph.append_node_attr(graph, subs_dof);
            m_graph.append_edge_attr(graph, subs_prev, subs_dof,
                    create_slink("COLOR", "u_sharp", 1, 1, 1, true));
            m_graph.append_edge_attr(graph, pp_y1, subs_dof, slink_dof_blurred_in1);
            m_graph.append_edge_attr(graph, pp_y2, subs_dof, slink_dof_blurred_in2);

        } else {

            var slink_blur_x_in = create_slink("COLOR", "u_color", 1, 1, 1, true);
            slink_blur_x_in.min_filter = m_tex.TF_LINEAR;
            slink_blur_x_in.mag_filter = m_tex.TF_LINEAR;

            var slink_blur_y_in = create_slink("COLOR", "u_color", 1, 1, 1, true);
            slink_blur_y_in.min_filter = m_tex.TF_LINEAR;
            slink_blur_y_in.mag_filter = m_tex.TF_LINEAR;

            var pp_x = m_subs.create_subs_postprocessing("X_BLUR");
            m_graph.append_node_attr(graph, pp_x);
            m_graph.append_edge_attr(graph, subs_prev, pp_x, slink_blur_x_in);

            var pp_y = m_subs.create_subs_postprocessing("Y_BLUR");
            m_graph.append_node_attr(graph, pp_y);
            m_graph.append_edge_attr(graph, pp_x, pp_y, slink_blur_y_in);

            var subs_dof_in = last_geom_level[0];
            var subs_dof = m_subs.create_subs_dof(cam_dof);
            cam_dof.dof_distance = cam_render.dof_distance;
            cam_dof.dof_object = cam_render.dof_object;
            cam_dof.dof_front_start = cam_render.dof_front_start;
            cam_dof.dof_front_end = cam_render.dof_front_end;
            cam_dof.dof_rear_start = cam_render.dof_rear_start;
            cam_dof.dof_rear_end = cam_render.dof_rear_end;
            cam_dof.dof_power = cam_render.dof_power;
            cam_dof.dof_bokeh = cam_render.dof_bokeh;
            cam_dof.dof_bokeh_intensity = cam_render.dof_bokeh_intensity;
            cam_dof.dof_foreground_blur = cam_render.dof_foreground_blur;
            cam_dof.dof_on = true;
            curr_level.push(subs_dof);

            m_graph.append_node_attr(graph, subs_dof);
            m_graph.append_edge_attr(graph, subs_prev, subs_dof,
                    create_slink("COLOR", "u_sharp", 1, 1, 1, true));
            m_graph.append_edge_attr(graph, pp_y, subs_dof,
                    create_slink("COLOR", "u_blurred", 1, 1, 1, true));
            m_graph.append_edge_attr(graph, subs_dof_in, subs_dof,
                    create_slink("DEPTH", "u_depth", 1, 1, 1, true));
        }

        prev_level = curr_level;
        curr_level = [];
    }

    // objects which are rendered above all
    if (sc_render.xray) {
        var subs_main_xray = create_custom_sub_main(m_subs.MAIN_XRAY);
        curr_level.push(subs_main_xray);

        prev_level = curr_level;
        curr_level = [];
    }

    // motion blur stuff
    if (motion_blur && !rtt) {

        var subs_to_blur = prev_level[0];
        var subs_mb = m_subs.create_subs_motion_blur(mb_params.mb_decay_threshold,
                mb_params.mb_factor);
        curr_level.push(subs_mb);

        m_graph.append_node_attr(graph, subs_mb);

        var slink_mb_in = create_slink("COLOR", "u_mb_tex_curr", 1, 1, 1, true);
        m_graph.append_edge_attr(graph, subs_to_blur, subs_mb, slink_mb_in);

        var slink_mb_accum = create_slink("COLOR", "u_mb_tex_accum", 1, 1, 1, true);
        subs_mb.slinks_internal.push(slink_mb_accum);

        prev_level = curr_level;
        curr_level = [];
    }

    // outline_mask
    if (!rtt && sc_render.outline) {
        var subs_prev = prev_level[0];

        var cam_outline = m_cam.clone_camera(main_cam, true);
        cam_scene_data.cameras.push(cam_outline);

        var subs_outline_mask = m_subs.create_subs_outline_mask(cam_outline, num_lights);
        m_graph.append_node_attr(graph, subs_outline_mask);

        var pp_x_ext = m_subs.create_subs_postprocessing("X_EXTEND");

        // almost the same
        var slink_mask_pp = create_slink("COLOR", "u_color", 1, 1, 1, true);
        var slink_mask_gl = create_slink("COLOR", "u_outline_mask", 1, 1, 1, true);

        pp_x_ext.is_for_outline = true;
        m_graph.append_node_attr(graph, pp_x_ext);
        m_graph.append_edge_attr(graph, subs_outline_mask, pp_x_ext,
                slink_mask_pp);

        var slink_ext = create_slink("COLOR", "u_color", 1, 0.5, 0.5, true);
        slink_ext.min_filter = m_tex.TF_LINEAR;
        slink_ext.mag_filter = m_tex.TF_LINEAR;

        var pp_y_ext = m_subs.create_subs_postprocessing("Y_EXTEND");
        pp_y_ext.is_for_outline = true;
        m_graph.append_node_attr(graph, pp_y_ext);
        m_graph.append_edge_attr(graph, pp_x_ext, pp_y_ext, slink_ext);

        var pp_x = m_subs.create_subs_postprocessing("X_BLUR");
        pp_x.is_for_outline = true;
        m_graph.append_node_attr(graph, pp_x);
        m_graph.append_edge_attr(graph, pp_y_ext, pp_x, slink_ext);

        // almost the same
        var slink_blur_blur = create_slink("COLOR", "u_color", 1, 0.25, 0.25, true);
        slink_blur_blur.min_filter = m_tex.TF_LINEAR;
        slink_blur_blur.mag_filter = m_tex.TF_LINEAR;
        var slink_blur_outline = create_slink("COLOR", "u_outline_mask_blurred", 1, 0.25, 0.25, true);
        slink_blur_outline.min_filter = m_tex.TF_LINEAR;
        slink_blur_outline.mag_filter = m_tex.TF_LINEAR;

        var pp_y = m_subs.create_subs_postprocessing("Y_BLUR");
        pp_y.is_for_outline = true;
        m_graph.append_node_attr(graph, pp_y);
        m_graph.append_edge_attr(graph, pp_x, pp_y, slink_blur_blur);

        var subs_outline = m_subs.create_subs_outline(outline_params);
        m_graph.append_node_attr(graph, subs_outline);

        m_graph.append_edge_attr(graph, subs_prev, subs_outline,
                create_slink("COLOR", "u_outline_src", 1, 1, 1, true));

        m_graph.append_edge_attr(graph, subs_outline_mask, subs_outline,
                slink_mask_gl);
        m_graph.append_edge_attr(graph, pp_y, subs_outline, slink_blur_outline);

        curr_level.push(subs_outline);

        prev_level = curr_level;
        curr_level = [];
    }

    enforce_slink_uniqueness(graph, depth_tex);
    if ((sc_render.anaglyph_use || sc_render.hmd_stereo_use) && !rtt) {
        var subs_stereo = make_stereo(graph, sc_render, cam_scene_data, prev_level[0]);
        curr_level.push(subs_stereo);

        prev_level = curr_level;
        curr_level = [];
    }

    // compositing
    if (compositing && !rtt) {

        var subs_prev = prev_level[0];

        var brightness = cc_params.brightness;
        var contrast   = cc_params.contrast;
        var exposure   = cc_params.exposure;
        var saturation = cc_params.saturation;

        var subs_compositing = m_subs.create_subs_compositing(brightness, contrast,
                                                      exposure, saturation);

        m_graph.append_node_attr(graph, subs_compositing);
        m_graph.append_edge_attr(graph, subs_prev, subs_compositing,
                create_slink("COLOR", "u_color", 1, 1, 1, true));

        curr_level.push(subs_compositing);

        prev_level = curr_level;
        curr_level = [];
    }

    // antialiasing stuff
    if (antialiasing) {
        var subs_prev = prev_level[0];

        if (cfg_def.smaa) {

            var slink_smaa_in = create_slink("COLOR", "u_color",
                                             1, 1, 1, true);
            slink_smaa_in.min_filter = m_tex.TF_LINEAR;
            slink_smaa_in.mag_filter = m_tex.TF_LINEAR;

            // NOTE: temoporary disabled T2X mode due to artifacts with blend objects
            //if (!m_cfg.context.alpha) {

            //    var depth_subs = find_upper_subs(graph, subs_prev, "DEPTH");

            //    // velocity buffer
            //    var cam_velocity = m_cam.clone_camera(main_cam, true);
            //    cam_scene_data.cameras.push(cam_velocity);

            //    var subs_velocity = m_subs.create_subs_veloctity(cam_velocity);
            //    var slink_velocity_in = create_slink("DEPTH", "u_depth",
            //                                     1, 1, 1, true);
            //    slink_velocity_in.min_filter = m_tex.TF_NEAREST;
            //    slink_velocity_in.mag_filter = m_tex.TF_NEAREST;

            //    m_graph.append_node_attr(graph, subs_velocity);
            //    m_graph.append_edge_attr(graph, depth_subs, subs_velocity,
            //                             slink_velocity_in);

            //    var slink_velocity_smaa = create_slink("COLOR", "u_velocity_tex",
            //                                     1, 1, 1, true);
            //}

            // 1-st pass - edge detection
            var subs_smaa_1 = m_subs.create_subs_smaa(m_subs.SMAA_EDGE_DETECTION, sc_render);
            m_graph.append_node_attr(graph, subs_smaa_1);

            m_graph.append_edge_attr(graph, subs_prev, subs_smaa_1,
                                     slink_smaa_in);

            // 2-nd pass - blending weight calculation
            var subs_smaa_2 = m_subs.create_subs_smaa(m_subs.SMAA_BLENDING_WEIGHT_CALCULATION, sc_render);
            m_graph.append_node_attr(graph, subs_smaa_2);
            m_graph.append_edge_attr(graph, subs_smaa_1, subs_smaa_2,
                                     slink_smaa_in);

            var slink_search_tex = create_slink("COLOR", "u_search_tex",
                                                1, 1, 1, false);
            var slink_area_tex = create_slink("COLOR", "u_area_tex",
                                                1, 1, 1, false);

            slink_search_tex.min_filter = m_tex.TF_LINEAR;
            slink_search_tex.mag_filter = m_tex.TF_LINEAR;
            slink_area_tex.min_filter   = m_tex.TF_LINEAR;
            slink_area_tex.mag_filter   = m_tex.TF_LINEAR;
            subs_smaa_2.slinks_internal.push(slink_search_tex);
            subs_smaa_2.slinks_internal.push(slink_area_tex);

            // 3-rd pass - neighborhood blending
            var subs_smaa_3 = m_subs.create_subs_smaa(m_subs.SMAA_NEIGHBORHOOD_BLENDING, sc_render);
            m_graph.append_node_attr(graph, subs_smaa_3);

            m_graph.append_edge_attr(graph, subs_prev,
                                     subs_smaa_3, slink_smaa_in);

            var slink_smaa_blend = create_slink("COLOR", "u_blend",
                                                1, 1, 1, true);
            slink_smaa_blend.min_filter = m_tex.TF_LINEAR;
            slink_smaa_blend.mag_filter = m_tex.TF_LINEAR;
            m_graph.append_edge_attr(graph, subs_smaa_2,
                                     subs_smaa_3, slink_smaa_blend);

            // 4-th pass - resolve

            // NOTE: temoporary disabled T2X mode due to artifacts with blend objects
            //if (!m_cfg.context.alpha) {
            //    m_graph.append_edge_attr(graph, subs_velocity, subs_smaa_3,
            //                             slink_velocity_smaa);
            //    var subs_smaa_r = m_subs.create_subs_smaa(m_subs.SMAA_RESOLVE, sc_render);
            //    m_graph.append_node_attr(graph, subs_smaa_r);

            //    m_graph.append_edge_attr(graph, subs_smaa_3, subs_smaa_r,
            //                             slink_smaa_in);
            //    m_graph.append_edge_attr(graph, subs_velocity, subs_smaa_r,
            //                             slink_velocity_smaa);

            //    var slink_smaa_in_prev = create_slink("COLOR", "u_color_prev",
            //                                          1, 1, 1, true);
            //    slink_smaa_in_prev.min_filter = m_tex.TF_LINEAR;
            //    slink_smaa_in_prev.mag_filter = m_tex.TF_LINEAR;

            //    subs_smaa_r.slinks_internal.push(slink_smaa_in_prev);

            //    curr_level.push(subs_smaa_r);
            //} else
                curr_level.push(subs_smaa_3);

        } else {
            var subs_aa = m_subs.create_subs_aa(sc_render);
            m_graph.append_node_attr(graph, subs_aa);

            var slink_aa_in = create_slink("COLOR", "u_color", 1, 1, 1, true);
            slink_aa_in.min_filter = m_tex.TF_LINEAR;
            slink_aa_in.mag_filter = m_tex.TF_LINEAR;
            m_graph.append_edge_attr(graph, subs_prev, subs_aa, slink_aa_in);

            curr_level.push(subs_aa);
        }

        prev_level = curr_level;
        curr_level = [];
    }

    // special precautions needed to prevent subscenes with through-going
    // attachments from on-screen or RTT (!!!) rendering
    // NOTE: it's not possible to resolve (blit) directly on screen framebuffer
    // NOTE: may be a Chromium bug
    var prev_id = m_graph.node_by_attr(graph, prev_level[0]);
    if (prev_level[0].type == m_subs.MOTION_BLUR ||
            prev_level[0].type == m_subs.RESOLVE)
        var need_subs_pp_copy = true;
    else {
        var need_subs_pp_copy = false;
        m_graph.traverse_inputs(graph, prev_id, function(id_in, attr_in,
                attr_edge) {
            var slink_in = attr_edge;
            if (slink_in.from == slink_in.to) {
                need_subs_pp_copy = true;
                return true;
            }
        });
    }

    if (need_subs_pp_copy) {
        var subs_pp_copy = m_subs.create_subs_postprocessing("NONE");
        m_graph.append_node_attr(graph, subs_pp_copy);
        m_graph.append_edge_attr(graph, prev_level[0], subs_pp_copy,
                create_slink("COLOR", "u_color", 1, 1, 1, true));

        curr_level.push(subs_pp_copy);
        prev_level = curr_level;
        curr_level = [];
    }

    // NOTE: from anaglyph
    curr_level.push(prev_level[0]);

    //
    // filling up the last level
    //

    if (subs_color_picking)
        if (subs_color_picking_xray)
            curr_level.push(subs_color_picking_xray);
        else
            curr_level.push(subs_color_picking);

    if (subs_anchor)
        curr_level.push(subs_anchor);

    var tex_size = cfg_scs.cubemap_tex_size;
    if (sc_render.sky_params.render_sky) {
        var sky_params = sc_render.sky_params;
        var wls = sc_render.world_light_set;
        var tex_param = wls.sky_texture_param;
        tex_size = tex_param ? tex_param.tex_size : tex_size;
        var subs_sky = m_subs.create_subs_sky(wls, num_lights, sky_params, tex_size);
        m_graph.append_node_attr(graph, subs_sky);

        curr_level.push(subs_sky);
    }

    var subs_sink = m_subs.create_subs_sink();
    m_graph.append_node_attr(graph, subs_sink);

    for (var i = 0; i < curr_level.length; i++) {
        var subs = curr_level[i];
        switch (subs.type) {
        case m_subs.COLOR_PICKING:
        case m_subs.COLOR_PICKING_XRAY:
            m_graph.append_edge_attr(graph, subs, subs_sink,
                    create_slink("COLOR", "NONE", 1, 1, 1, false));
            m_graph.append_edge_attr(graph, subs, subs_sink,
                    create_slink("DEPTH", "NONE", 1, 1, 1, false));
            break;
        case m_subs.SKY:
            var slink_sky = create_slink("CUBEMAP", "u_sky",
                    tex_size, 1, 1, false);
            m_graph.append_edge_attr(graph, subs, subs_sink, slink_sky);
            break;
        case m_subs.ANCHOR_VISIBILITY:
            var slink_anchor_color = create_slink("COLOR", "NONE", 1, 1, 1, true);
            m_graph.append_edge_attr(graph, subs, subs_sink, slink_anchor_color);
            break;
        default:

            if (rtt) {
                var tex0 = render_to_textures[0];

                var slink_rtt = create_slink("COLOR", "OFFSCREEN", 1, 1, 1, true);
                slink_rtt.texture = tex0;

                // first one connected directly to SINK
                m_graph.append_edge_attr(graph, curr_level[i], subs_sink, slink_rtt);

                for (var j = 1; j < render_to_textures.length; j++) {
                    var tex = render_to_textures[j];

                    var subs_scale = m_subs.create_subs_postprocessing("NONE");
                    m_graph.append_node_attr(graph, subs_scale);

                    var slink_to_rtt = create_slink("COLOR", "SCALE", 1, 1, 1, true);

                    m_graph.append_edge_attr(graph, curr_level[i], subs_scale,
                            slink_to_rtt);

                    // copied textures have smaller size
                    var size_mult = tex.source_size / tex0.source_size;

                    var slink_rtt = create_slink("COLOR", "OFFSCREEN", 1,
                            size_mult, size_mult, true);
                    slink_rtt.texture = tex;

                    m_graph.append_edge_attr(graph, subs_scale, subs_sink, slink_rtt);
                }
            } else
                m_graph.append_edge_attr(graph, curr_level[i], subs_sink,
                        create_slink("SCREEN", "NONE", 1, 1, 1, true));
            break;
        }
    }
    // remove unconnected opaque resolve node
    if (subs_res_opaque && !get_outputs(graph, subs_res_opaque).length) {
        m_graph.remove_node(graph,
                m_graph.node_by_attr(graph, subs_res_opaque));
        m_graph.cleanup_loose_edges(graph);
    }
    enforce_slink_uniqueness(graph, depth_tex);
    enforce_graph_consistency(graph, depth_tex);

    if (cfg_dbg.enabled) {
        var subs_from = find_debug_subs(graph);
        if (subs_from)
            assign_debug_subscene(graph, subs_from);
    }

    process_subscene_links(graph);
    assign_render_targets(graph);

    if (shadow_params) {
        m_graph.traverse(graph, function(nid, subs) {
            if (subs.type == m_subs.SHADOW_RECEIVE ||
                    subs.type == m_subs.MAIN_BLEND ||
                    subs.type == m_subs.MAIN_XRAY)
                prepare_shadow_receive_subs(graph, subs);
        });
    }

    return graph;
}

function find_debug_subs(graph) {
    var subs_dbg = null;
    var subs_num = 0;

    m_graph.traverse(graph, function(id, attr) {
        if (attr.type == cfg_dbg.subs_type) {
            if (subs_num == cfg_dbg.subs_number) {
                subs_dbg = attr;
                return true;
            } else
                subs_num++;
        }
    });

    return subs_dbg;
}

function assign_debug_subscene(graph, subs_to_debug) {

    var node_to_debug = m_graph.node_by_attr(graph, subs_to_debug);

    var subs_debug_view = m_subs.create_subs_postprocessing("NONE");
    var node_debug_view = m_graph.append_node_attr(graph, subs_debug_view);

    var node_sink = m_graph.get_sink_nodes(graph)[0];

    m_graph.traverse_edges(graph, function(edge_from, edge_to, edge_attr) {

        if (edge_to == node_sink) {
            m_graph.reconnect_edges(graph, edge_from, node_sink, edge_from, node_debug_view);
        }
    });

    var has_multisample = subs_check_multisample(subs_to_debug, graph);

    m_graph.traverse_edges(graph, function(edge_from, edge_to, edge_attr) {
        if (edge_from == node_to_debug) {

            if (has_multisample) {
                var subs_res_geom = m_subs.create_subs_resolve();
                m_graph.append_node_attr(graph, subs_res_geom);

                var slink_resolve_in_c = create_slink("COLOR", "RESOLVE", 1, 1, 1, true);
                slink_resolve_in_c.multisample = true;
                slink_resolve_in_c.use_renderbuffer = true;
                var slink_resolve_in_d = create_slink("DEPTH", "RESOLVE", 1, 1, 1, true);
                slink_resolve_in_d.multisample = true;
                slink_resolve_in_d.use_renderbuffer = true;

                m_graph.append_edge_attr(graph, subs_to_debug, subs_res_geom, slink_resolve_in_c);
                m_graph.append_edge_attr(graph, subs_to_debug, subs_res_geom, slink_resolve_in_d);

                subs_to_debug = subs_res_geom;
            }

            m_graph.append_edge_attr(graph, subs_to_debug, subs_debug_view,
                    create_slink(cfg_dbg.slink_type, "u_color", edge_attr.size,
                    edge_attr.size_mult_x, edge_attr.size_mult_y,
                    edge_attr.update_dim));
            return true;
        }
    });

    m_graph.append_edge(graph, node_debug_view, node_sink,
            create_slink("SCREEN", "NONE", 0.5, 0.5, 0.5, true));
}

function subs_check_multisample(subs, graph) {
    var has_multisample = false;

    var node = m_graph.node_by_attr(graph, subs);

    // node without output edges has not multisampling
    if (m_graph.out_edge_count(graph, node)) {
        var node_out = m_graph.get_out_edge(graph, node, 0);
        var edge_attr = m_graph.get_edge_attr(graph, node, node_out, 0);

        if (edge_attr.from == "COLOR" && edge_attr.to == "COLOR" 
                || edge_attr.from == "DEPTH" && edge_attr.to == "DEPTH") {
            var attr_out = m_graph.get_node_attr(graph, node_out);
            has_multisample = subs_check_multisample(attr_out, graph);
        } else
            has_multisample = edge_attr.to == "RESOLVE";
    }

    return has_multisample;
}

function make_stereo(graph, sc_render, cam_scene_data, prev_subs) {
    var cams = cam_scene_data.cameras;
    var antialiasing = sc_render.antialiasing;
    var hmd_stereo_use = sc_render.hmd_stereo_use;
    var plane_refl_subs = sc_render.reflection_params.plane_refl_subs;
    var plane_refl_subs_blend = sc_render.reflection_params.plane_refl_subs_blend;

    var nid_pre_sink = m_graph.get_node_id(graph, prev_subs);
    var subs_pre_sink = prev_subs;

    var subgraph_right = m_graph.subgraph_node_conn(graph, nid_pre_sink,
            m_graph.BACKWARD_DIR);

    // [[original left only subscene, new right subscene, original slink]...]
    var left_only_edges = [];
    var removed_subscenes = [];
    var source_nodes_right = [];

    var subs_clone_cb = function(subs) {
        var subs_new;

        // shared
        if (LEFT_ONLY_SUBS_TYPES.indexOf(subs.type) > -1) {
            removed_subscenes.push(subs);
            subs_new = subs;
        } else {
            subs_new = m_subs.clone_subs(subs);
            if (subs_new.type == m_subs.MAIN_PLANE_REFLECT) {
                // NOTE: x[0] --- left eye
                for (var i = 0; i < plane_refl_subs.length; i++) {
                    if (plane_refl_subs[i][0] == subs) {
                        plane_refl_subs[i] = [subs, subs_new];
                        subs_new.camera.reflection_plane = subs.camera.reflection_plane;
                        cam_scene_data.cameras.push(subs_new.camera);
                        break;
                    }
                }
            }

            // just copy camera from opaque scene for blend reflection
            if (subs.type == m_subs.MAIN_PLANE_REFLECT_BLEND) {
                // NOTE: x[0] --- left eye
                for (var i = 0; i < plane_refl_subs.length; i++) {
                    if (plane_refl_subs_blend[i][0] == subs) {
                        plane_refl_subs_blend[i] = [subs, subs_new];
                        subs_new.camera = plane_refl_subs[i][1].camera;
                        break;
                    }
                }
            } else if (cams.indexOf(subs.camera) > -1) {
                if (hmd_stereo_use) {
                    m_cam.make_stereo(subs.camera, m_cam.TYPE_HMD_LEFT);
                    m_cam.make_stereo(subs_new.camera, m_cam.TYPE_HMD_RIGHT);
                } else {
                    m_cam.make_stereo(subs.camera, m_cam.TYPE_STEREO_LEFT);
                    m_cam.make_stereo(subs_new.camera, m_cam.TYPE_STEREO_RIGHT);
                }
                cams.push(subs_new.camera);
            }

            var nid_subs = m_graph.node_by_attr(graph, subs);
            m_graph.traverse_inputs(graph, nid_subs, function(nid_in, subs_in,
                    slink) {
                if (LEFT_ONLY_SUBS_TYPES.indexOf(subs_in.type) > -1)
                    left_only_edges.push([subs_in, subs_new, slink]);
            });

            if (subs.type !== m_subs.MOTION_BLUR)
                for (var i = 0; i < subs.slinks_internal.length; i++)
                    subs_new.slinks_internal[i].parent_slink = subs.slinks_internal[i];

            // render order: store source nodes for right eye
            var is_source_node = true;
            for (var i = 0; i < m_graph.in_edge_count(graph, nid_subs); i++) {
                var nid_upper_subs = m_graph.get_in_edge(graph, nid_subs, i);
                var upper_subs = m_graph.get_node_attr(graph, nid_upper_subs);
                if (LEFT_ONLY_SUBS_TYPES.indexOf(upper_subs.type) == -1)
                    is_source_node = false;
            }

            if (is_source_node)
                source_nodes_right.push(subs_new);
        }

        return subs_new;
    }
    var slink_clone_cb = function(slink) {
        var new_slink = clone_slink(slink, true);
        new_slink.parent_slink = slink;
        return new_slink;
    }
    subgraph_right = m_graph.clone(subgraph_right, subs_clone_cb, slink_clone_cb);

    m_graph.traverse_edges(subgraph_right, function(node1, node2, slink) {
        var subs = m_graph.get_node_attr(subgraph_right, node1);
        if (subs.type === m_subs.MOTION_BLUR)
            slink.parent_slink = null;
    });

    for (var i = 0; i < removed_subscenes.length; i++)
        m_graph.remove_node(subgraph_right,
                m_graph.node_by_attr(subgraph_right, removed_subscenes[i]));

    m_graph.cleanup_loose_edges(subgraph_right);

    var subs_stereo = m_subs.create_subs_stereo(hmd_stereo_use);
    var nid_stereo = m_graph.append_node_attr(graph, subs_stereo);

    // HACK: fix subs texture reusage of last left subs
    var left_clone = m_subs.create_subs_copy();
    m_graph.append_node_attr(graph, left_clone);

    var slink_left_copy = create_slink("COLOR", "COPY", 1, 1, 1, true);
    m_graph.append_edge_attr(graph, subs_pre_sink, left_clone, slink_left_copy);

    var slink_left = create_slink("COLOR", "u_sampler_left", 1, 1, 1, true);
    slink_left.unique_texture = true;
    slink_left.min_filter = m_tex.TF_LINEAR;
    slink_left.mag_filter = m_tex.TF_LINEAR;

    m_graph.append_edge_attr(graph, left_clone, subs_stereo, slink_left);

    if (!subs_pre_sink.is_pp) {
        var right_clone = m_subs.create_subs_copy();
        m_graph.append_node_attr(subgraph_right, right_clone);
        var slink_right_copy = create_slink("COLOR", "COPY", 1, 1, 1, true);
        slink_right_copy.parent_slink = slink_left_copy;
        var nid_right_sink = m_graph.get_sink_nodes(subgraph_right)[0];
        var right_sink = m_graph.get_node_attr(subgraph_right, nid_right_sink);
        m_graph.append_edge_attr(subgraph_right, right_sink, right_clone, slink_right_copy);
    }

    var slink_right = create_slink("COLOR", "u_sampler_right", 1, 1, 1, true);
    slink_right.min_filter = m_tex.TF_LINEAR;
    slink_right.mag_filter = m_tex.TF_LINEAR;
    m_graph.append_subgraph(subgraph_right, graph,
            [m_graph.get_sink_nodes(subgraph_right)[0], nid_stereo,
            slink_right]
    );

    for (var i = 0; i < left_only_edges.length; i++) {
        var subs1 = left_only_edges[i][0];
        var subs2 = left_only_edges[i][1];
        var slink = left_only_edges[i][2];
        m_graph.append_edge_attr(graph, subs1, subs2, slink);
    }

    // render order: left eye before right eye
    var slink_order = create_slink("SCREEN", "NONE", 0, 0, 0, false);
    for (var i = 0; i < source_nodes_right.length; i++)
        m_graph.append_edge_attr(graph, left_clone, source_nodes_right[i], slink_order);

    // resize subs texture for hmd
    if (hmd_stereo_use)
        multiply_size_mult_by_graph(graph, 0.5, 1);

    return subs_stereo;
}

exports.multiply_size_mult_by_graph = multiply_size_mult_by_graph;
function multiply_size_mult_by_graph(graph, multiplier_x, multiplier_y) {
    var slink_list = [];
    m_graph.traverse(graph, function(subs_id, subs) {
        if (LEFT_ONLY_SUBS_TYPES.indexOf(subs.type) == -1 &&
                subs.slinks_internal.length &&
                has_lower_subs(graph, subs, m_subs.STEREO)) {
            for (var i = 0; i < subs.slinks_internal.length; i++) {
                var slink = subs.slinks_internal[i];
                if (slink_list.indexOf(slink) == -1)
                    slink_list.push(slink);
            }
        }
    });
    m_graph.traverse_edges(graph, function(node1, node2, slink) {
        var subs1 = m_graph.get_node_attr(graph, node1);
        var subs2 = m_graph.get_node_attr(graph, node2);
        if (LEFT_ONLY_SUBS_TYPES.indexOf(subs1.type) == -1 &&
                has_lower_subs(graph, subs2, m_subs.STEREO)) {
            if (slink_list.indexOf(slink) == -1)
                slink_list.push(slink);
        }
    });

    for (var i = 0; i < slink_list.length; i++) {
        slink_list[i].size_mult_x *= multiplier_x;
        slink_list[i].size_mult_y *= multiplier_y;
    }
}

/**
 * Set subs texel size
 */
exports.set_texel_size = set_texel_size;
function set_texel_size(subs, size_x, size_y) {
    var mult = subs.texel_size_multiplier;
    subs.texel_size[0] = size_x * subs.texel_mask[0] * mult;
    subs.texel_size[1] = size_y * subs.texel_mask[1] * mult;
}

/**
 * Set subs texel size multiplier.
 * Use set_texel_size() to update shader uniforms
 */
exports.set_texel_size_mult = set_texel_size_mult;
function set_texel_size_mult(subs, mult) {
    subs.texel_size_multiplier = mult;
}

function create_slink(from, to, size, size_mult_x, size_mult_y, update_dim) {
    var slink = {
        // assign explicitly in all cases
        from: from,
        to: to,
        size: size,
        size_mult_x: size_mult_x,
        size_mult_y: size_mult_y,
        update_dim: update_dim,

        // generic default values
        active: true,
        texture: null,
        multisample: false,
        use_renderbuffer: false,
        min_filter: m_tex.TF_NEAREST,
        mag_filter: m_tex.TF_NEAREST,
        unique_texture: false,
        use_comparison: false
    };

    return slink;
}

function clone_slink(slink, tex_by_link) {

    if (tex_by_link) {
        var tex = slink.texture;
        slink.texture = null;
    }

    if (slink.texture)
        m_util.panic("Failed to clone slink with attached texture");

    var slink_new = m_util.clone_object_json(slink);

    if (tex_by_link) {
        slink.texture = tex;
        slink_new.texture = tex;
    }

    return slink_new;
}

function prepare_shadow_receive_subs(graph, subs) {

    var csm_index = 0;
    var subs_inputs = get_inputs(graph, subs);
    var v_light_tsr_num = 0;

    for (var i = 0; i < subs_inputs.length; i++) {

        var input = subs_inputs[i];

        // shadow map with optional blurring
        if (input.type == m_subs.SHADOW_CAST) {
            v_light_tsr_num++;

            subs.p_light_matrix = subs.p_light_matrix || new Array();

            var index = input.shadow_lamp_index > 0 ? input.shadow_lamp_index : csm_index;
            // assign uniforms from cast camera by link
            subs.p_light_matrix[index] = input.camera.proj_matrix;

            csm_index++;
        }
    }

    if (!subs.v_light_ts || !subs.v_light_r) {
        if (cfg_def.mac_os_shadow_hack)
            subs.v_light_tsr = new Float32Array(v_light_tsr_num * 9);
        else {
            subs.v_light_ts = new Float32Array(v_light_tsr_num * 4);
            subs.v_light_r = new Float32Array(v_light_tsr_num * 4);
        }
    }

}

exports.create_performance_graph = function() {
    var graph = m_graph.create();

    var subs_perf = m_subs.create_subs_perf();
    var cam = m_cam.create_camera(m_cam.TYPE_NONE);
    var size = 512;
    cam.width = size;
    cam.height = size;
    subs_perf.camera = cam;
    m_graph.append_node_attr(graph, subs_perf);

    subs_perf.slinks_internal.push(create_slink("COLOR",
            "u_color", size, 1, 1, false));

    var subs_sink = m_subs.create_subs_sink();
    m_graph.append_node_attr(graph, subs_sink);

    m_graph.append_edge_attr(graph, subs_perf, subs_sink,
            create_slink("COLOR", "NONE", size, 1, 1, false));
    //        create_slink("SCREEN", "NONE", size, 1, 1, false));

    process_subscene_links(graph);
    assign_render_targets(graph);

    return graph;
}

/**
 * Find first on-screen subscene.
 */
exports.find_on_screen = function(graph) {

    var subs = null;

    m_graph.traverse(graph, function(node, attr) {
        if (attr.camera && attr.camera.framebuffer === null) {
            subs = attr;
            return true;
        }
        return false;
    });

    return subs;
}

/**
 * Find input of given type.
 */
exports.find_input = function(graph, subs, type) {
    var inputs = get_inputs(graph, subs);
    for (var i = 0; i < inputs.length; i++)
        if (inputs[i].type == type)
            return inputs[i];

    return null;
}

/**
 * Get inputs of given type.
 */
exports.get_inputs_by_type = function(graph, subs, type) {
    var inputs = get_inputs(graph, subs);
    var matching_inputs = [];

    for (var i = 0; i < inputs.length; i++)
        if (inputs[i].type == type)
            matching_inputs.push(inputs[i]);

    return matching_inputs;
}

exports.has_lower_subs = has_lower_subs;
/**
 * Traverse graph downwards and check if subs has output of given type.
 * subs itself also checked
 * @methodOf graph
 */
function has_lower_subs(graph, subs, type) {

    if (subs.type == type)
        return true;

    var outputs = get_outputs(graph, subs);
    for (var i = 0; i < outputs.length; i++)
        if (has_lower_subs(graph, outputs[i], type))
            return true;

    return false;
}

exports.has_upper_subs = has_upper_subs;
/**
 * Traverse graph upwards and check if subs has input of given type.
 * subs itself also checked
 * @methodOf graph
 */
function has_upper_subs(graph, subs, type) {

    if (subs.type == type)
        return true;

    var inputs = get_inputs(graph, subs);
    for (var i = 0; i < inputs.length; i++)
        if (has_upper_subs(graph, inputs[i], type))
            return true;

    return false;
}

/**
 * Traverse graph upwards and find first subscene of given type.
 * subs itself also may be found,
 * @methodOf graph
 */
function find_upper_subs(graph, subs, type) {
    if (subs.type == type)
        return subs;

    var inputs = get_inputs(graph, subs);
    for (var i = 0; i < inputs.length; i++) {
        var upper = find_upper_subs(graph, inputs[i], type);
        if (upper)
            return upper;
    }

    return null;
}

exports.get_inputs = get_inputs;
function get_inputs(graph, subs) {
    var node = m_graph.node_by_attr(graph, subs);
    if (node == m_graph.NULL_NODE)
        m_util.panic("Subscene not in graph");

    var inputs = [];

    var in_edge_count = m_graph.in_edge_count(graph, node);
    for (var i = 0; i < in_edge_count; i++) {
        var node_input = m_graph.get_in_edge(graph, node, i);
        if (node_input != node)
            inputs.push(m_graph.get_node_attr(graph, node_input));
    }
    return inputs;
}

exports.get_outputs = get_outputs;
function get_outputs(graph, subs) {
    var node = m_graph.node_by_attr(graph, subs);
    if (node == m_graph.NULL_NODE)
        m_util.panic("Subscene not in graph");

    var outputs = [];

    var out_edge_count = m_graph.out_edge_count(graph, node);
    for (var i = 0; i < out_edge_count; i++) {
        var node_output = m_graph.get_out_edge(graph, node, i);
        if (node_output != node)
            outputs.push(m_graph.get_node_attr(graph, node_output));
    }
    return outputs;
}

/**
 * Find first subscene in graph/array matching given type
 */
exports.find_subs = function(graph, type) {
    var subs = null;

    m_graph.traverse(graph, function(node, attr) {
        if (attr.type == type) {
            subs = attr;
            return true;
        }
        return false;
    });

    return subs;
}

exports.debug_convert_to_dot = function(graph) {

    var PAPER_SIZE = "11.7,16.5";   // A3
    //var PAPER_SIZE = "8.3,11.7";    // A4

    var dot_str = "digraph scenegraph {\n";

    dot_str += "    ";
    dot_str += "size=\"" + PAPER_SIZE + "\";\n";
    dot_str += "    ";
    dot_str += "ratio=\"fill\";\n";

    dot_str += "    ";
    dot_str += "node [shape=box margin=\"0.25,0.055\"];\n"

    var tex_ids = debug_calc_tex_ids(graph);

    m_graph.traverse(graph, function(node, attr) {
        dot_str += "    ";
        dot_str += dot_format_node(node, attr, tex_ids);
    });

    m_graph.traverse_edges(graph, function(node1, node2, attr) {
        dot_str += "    ";
        dot_str += dot_format_edge(node1, node2, attr, tex_ids);
    });

    dot_str += "}";

    return dot_str;
}

function debug_calc_tex_ids(graph) {
    var index_buf = [];
    var ids = [];

    traverse_slinks(graph, function(slink, internal, subs1, subs2) {
        if (slink.texture) {
            var num = index_buf.indexOf(slink.texture);
            if (num == -1) {
                index_buf.push(slink.texture);
                ids.push(slink.texture, index_buf.length - 1);
            }
        }
    });

    return ids;
}

function dot_format_node(node, subs, tex_ids) {
    var cam = subs.camera;

    var label = m_subs.subs_label(subs);

    if (subs.camera) {
        label += "\\n"
        for (var i = 0; i < tex_ids.length; i+=2) {
            var c_att = subs.camera.color_attachment;
            if (tex_ids[i] == c_att) {
                if (m_tex.is_renderbuffer(c_att))
                    label += "CR" + tex_ids[i+1] + " ";
                else
                    label += "C" + tex_ids[i+1] + " ";
            }
        }
        for (var i = 0; i < tex_ids.length; i+=2) {
            var d_att = subs.camera.depth_attachment
            if (tex_ids[i] == d_att) {
                if (m_tex.is_renderbuffer(d_att))
                    label += "DR" + tex_ids[i+1];
                else
                    label += "D" + tex_ids[i+1];
            }
        }
    }

    if (subs.slinks_internal.length)
        label += "\\n-----\\n";

    for (var i = 0; i < subs.slinks_internal.length; i++)
        label += dot_format_edge_label(subs.slinks_internal[i], node, null,
                tex_ids);

    var color = "black";

    if (subs.type == m_subs.SINK)
        var style = "dotted";
    else if (subs.enqueue)
        var style = "solid";
    else
        var style = "dashed";

    style += ",bold";

    return String(node) + " [label=\"" + label + "\" " +
        "color=\"" + color + "\" " +
        "style=\"" + style + "\"" +
        "];\n";
}

function dot_format_edge(node1, node2, slink, tex_ids) {
    var label = dot_format_edge_label(slink, node1, node2, tex_ids);

    if (slink.active)
        var style = "solid";
    else
        var style = "dotted";

    return String(node1) + " -> " + String(node2) + " [label=\"" + label + "\" " +
            "style=\"" + style + "\"];\n";
}

function dot_format_edge_label(slink, node1, node2, tex_ids) {
    function filters_to_string(filters) {
        var string = "";

        if (filters.min == m_tex.TF_LINEAR)
            string += "L";
        else if (filters.min == m_tex.TF_NEAREST)
            string += "N";

        if (filters.mag == m_tex.TF_LINEAR)
            string += "L";
        else if (filters.mag == m_tex.TF_NEAREST)
            string += "N";

        return string;
    };

    var label = "";

    label += slink.from + "\\n"
    label += slink.to != "NONE" ? slink.to + "\\n" : "";

    label += "("

    if (slink.update_dim) {

        var size_mult_x = slink.size_mult_x;
        var size_mult_y = slink.size_mult_y;

        if (Math.round(size_mult_x) != size_mult_x)
            size_mult_x = size_mult_x.toFixed(2);
        if (Math.round(size_mult_y) != size_mult_y)
            size_mult_y = size_mult_y.toFixed(2);

        var size_x = (size_mult_x == 1 ? "" : size_mult_x) + "S";
        var size_y = (size_mult_y == 1 ? "" : size_mult_y) + "S";
        label += size_x + "x" + size_y;
    } else {
        var size_mult_x = slink.size_mult_x;
        var size_mult_y = slink.size_mult_y;
        label += slink.size * size_mult_x + "x" + slink.size * size_mult_y;
    }

    if (slink.from != "SCREEN") {
        label += " ";

        // texture filtering
        if (slink.use_renderbuffer)
            label += "RR";
        else
            label += filters_to_string({min: slink.min_filter, mag: slink.mag_filter});

        // texture ID number (sharing info)
        for (var i = 0; i < tex_ids.length; i+=2) {
            if (tex_ids[i] == slink.texture)
                label += " " + tex_ids[i+1];
        }
    }

    label += ")" + "\\n"

    return label;
}

/**
 * Create new rendering queue based on graph structure.
 * Perform topological sorting based on depth-first search algorithm.
 * @param graph Rendering graph array
 * @param [subs_sink] Root subscene node
 */
exports.create_rendering_queue = function(graph) {

    var subscenes = m_graph.topsort_attr(graph);
    var queue = [];

    for (var i = 0; i < subscenes.length; i++) {
        var subs = subscenes[i];
        if (subs.enqueue)
            queue.push(subs);
    }

    return queue;
}

}