# Code coverage report for src/Renderer.js

# all files / src/ Renderer.js

70.02% Statements 313/447
61.96% Branches 171/276
46.51% Functions 20/43
70.02% Lines 313/447

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     // TODO Resources like shader, texture, geometry reference management
    // Trace and find out which shader, texture, geometry can be destroyed
    import Base from './core/Base';
    import GLInfo from './core/GLInfo';
    import glenum from './core/glenum';
    import vendor from './core/vendor';
    import BoundingBox from './math/BoundingBox';
    import Matrix4 from './math/Matrix4';
    import Material from './Material';
    import Vector2 from './math/Vector2';
    import ProgramManager from './gpu/ProgramManager';

    // Light header
    import Shader from './Shader';

    import lightShader from './shader/source/header/light';
    import prezEssl from './shader/source/prez.glsl.js';
    Shader['import'](lightShader);
    Shader['import'](prezEssl);

    import glMatrix from './dep/glmatrix';
    var mat4 = glMatrix.mat4;
    var vec3 = glMatrix.vec3;

    var mat4Create = mat4.create;

    var errorShader = {};

    function defaultGetMaterial(renderable) {
        return renderable.material;
    }

    function noop() {}

    var attributeBufferTypeMap = {
        float: glenum.FLOAT,
        byte: glenum.BYTE,
        ubyte: glenum.UNSIGNED_BYTE,
        short: glenum.SHORT,
        ushort: glenum.UNSIGNED_SHORT
    };

    function VertexArrayObject(availableAttributes, availableAttributeSymbols, indicesBuffer) {
        this.availableAttributes = availableAttributes;
        this.availableAttributeSymbols = availableAttributeSymbols;
        this.indicesBuffer = indicesBuffer;

        this.vao = null;
    }
    /**
     * @constructor clay.Renderer
     */
    var Renderer = Base.extend(function () {
        return /** @lends clay.Renderer# */ {

            /**
             * @type {HTMLCanvasElement}
             * @readonly
             */
            canvas: null,

            /**
             * Canvas width, set by resize method
             * @type {number}
             * @private
             */
            _width: 100,

            /**
             * Canvas width, set by resize method
             * @type {number}
             * @private
             */
            _height: 100,

            /**
             * Device pixel ratio, set by setDevicePixelRatio method
             * Specially for high defination display
             * @see http://www.khronos.org/webgl/wiki/HandlingHighDPI
             * @type {number}
             * @private
             */
            devicePixelRatio: (window && window.devicePixelRatio) || 1.0,

            /**
             * Clear color
             * @type {number[]}
             */
            clearColor: [0.0, 0.0, 0.0, 0.0],

            /**
             * Default:
             *     _gl.COLOR_BUFFER_BIT | _gl.DEPTH_BUFFER_BIT | _gl.STENCIL_BUFFER_BIT
             * @type {number}
             */
            clearBit: 17664,

            // Settings when getting context
            // http://www.khronos.org/registry/webgl/specs/latest/#2.4

            /**
             * If enable alpha, default true
             * @type {boolean}
             */
            alpha: true,
            /**
             * If enable depth buffer, default true
             * @type {boolean}
             */
            depth: true,
            /**
             * If enable stencil buffer, default false
             * @type {boolean}
             */
            stencil: false,
            /**
             * If enable antialias, default true
             * @type {boolean}
             */
            antialias: true,
            /**
             * If enable premultiplied alpha, default true
             * @type {boolean}
             */
            premultipliedAlpha: true,
            /**
             * If preserve drawing buffer, default false
             * @type {boolean}
             */
            preserveDrawingBuffer: false,
            /**
             * If throw context error, usually turned on in debug mode
             * @type {boolean}
             */
            throwError: true,
            /**
             * WebGL Context created from given canvas
             * @type {WebGLRenderingContext}
             */
            gl: null,
            /**
             * Renderer viewport, read-only, can be set by setViewport method
             * @type {Object}
             */
            viewport: {},

            // Set by FrameBuffer#bind
            __currentFrameBuffer: null,

            _viewportStack: [],
            _clearStack: [],

            _sceneRendering: null
        };
    }, function () {

        Iif (!this.canvas) {
            this.canvas = document.createElement('canvas');
        }
        var canvas = this.canvas;
        try {
            var opts = {
                alpha: this.alpha,
                depth: this.depth,
                stencil: this.stencil,
                antialias: this.antialias,
                premultipliedAlpha: this.premultipliedAlpha,
                preserveDrawingBuffer: this.preserveDrawingBuffer
            };

            this.gl = canvas.getContext('webgl', opts)
                || canvas.getContext('experimental-webgl', opts);

            Iif (!this.gl) {
                throw new Error();
            }

            this._glinfo = new GLInfo(this.gl);

            Iif (this.gl.targetRenderer) {
                console.error('Already created a renderer');
            }
            this.gl.targetRenderer = this;

            this.resize();
        }
        catch (e) {
            throw 'Error creating WebGL Context ' + e;
        }

        // Init managers
        this._programMgr = new ProgramManager(this);
    },
    /** @lends clay.Renderer.prototype. **/
    {
        /**
         * Resize the canvas
         * @param {number} width
         * @param {number} height
         */
        resize: function(width, height) {
            var canvas = this.canvas;
            // http://www.khronos.org/webgl/wiki/HandlingHighDPI
            // set the display size of the canvas.
            var dpr = this.devicePixelRatio;
            if (width != null) {
                canvas.style.width = width + 'px';
                canvas.style.height = height + 'px';
                // set the size of the drawingBuffer
                canvas.width = width * dpr;
                canvas.height = height * dpr;

                this._width = width;
                this._height = height;
            }
            else {
                this._width = canvas.width / dpr;
                this._height = canvas.height / dpr;
            }

            this.setViewport(0, 0, this._width, this._height);
        },

        /**
         * Get renderer width
         * @return {number}
         */
        getWidth: function () {
            return this._width;
        },

        /**
         * Get renderer height
         * @return {number}
         */
        getHeight: function () {
            return this._height;
        },

        /**
         * Get viewport aspect,
         * @return {number}
         */
        getViewportAspect: function () {
            var viewport = this.viewport;
            return viewport.width / viewport.height;
        },

        /**
         * Set devicePixelRatio
         * @param {number} devicePixelRatio
         */
        setDevicePixelRatio: function(devicePixelRatio) {
            this.devicePixelRatio = devicePixelRatio;
            this.resize(this._width, this._height);
        },

        /**
         * Get devicePixelRatio
         * @param {number} devicePixelRatio
         */
        getDevicePixelRatio: function () {
            return this.devicePixelRatio;
        },

        /**
         * Get WebGL extension
         * @param {string} name
         * @return {object}
         */
        getGLExtension: function (name) {
            return this._glinfo.getExtension(name);
        },

        /**
         * Get WebGL parameter
         * @param {string} name
         * @return {*}
         */
        getGLParameter: function (name) {
            return this._glinfo.getParameter(name);
        },

        /**
         * Set rendering viewport
         * @param {number|Object} x
         * @param {number} [y]
         * @param {number} [width]
         * @param {number} [height]
         * @param {number} [devicePixelRatio]
         *        Defaultly use the renderere devicePixelRatio
         *        It needs to be 1 when setViewport is called by frameBuffer
         *
         * @example
         *  setViewport(0,0,width,height,1)
         *  setViewport({
         *      x: 0,
         *      y: 0,
         *      width: width,
         *      height: height,
         *      devicePixelRatio: 1
         *  })
         */
        setViewport: function (x, y, width, height, dpr) {

            if (typeof x === 'object') {
                var obj = x;

                x = obj.x;
                y = obj.y;
                width = obj.width;
                height = obj.height;
                dpr = obj.devicePixelRatio;
            }
            dpr = dpr || this.devicePixelRatio;

            this.gl.viewport(
                x * dpr, y * dpr, width * dpr, height * dpr
            );
            // Use a fresh new object, not write property.
            this.viewport = {
                x: x,
                y: y,
                width: width,
                height: height,
                devicePixelRatio: dpr
            };
        },

        /**
         * Push current viewport into a stack
         */
        saveViewport: function () {
            this._viewportStack.push(this.viewport);
        },

        /**
         * Pop viewport from stack, restore in the renderer
         */
        restoreViewport: function () {
            if (this._viewportStack.length > 0) {
                this.setViewport(this._viewportStack.pop());
            }
        },

        /**
         * Push current clear into a stack
         */
        saveClear: function () {
            this._clearStack.push({
                clearBit: this.clearBit,
                clearColor: this.clearColor
            });
        },

        /**
         * Pop clear from stack, restore in the renderer
         */
        restoreClear: function () {
            if (this._clearStack.length > 0) {
                var opt = this._clearStack.pop();
                this.clearColor = opt.clearColor;
                this.clearBit = opt.clearBit;
            }
        },

        bindSceneRendering: function (scene) {
            this._sceneRendering = scene;
        },

        /**
         * Render the scene in camera to the screen or binded offline framebuffer
         * @param  {clay.Scene}       scene
         * @param  {clay.Camera}      camera
         * @param  {boolean}     [notUpdateScene] If not call the scene.update methods in the rendering, default true
         * @param  {boolean}     [preZ]           If use preZ optimization, default false
         * @return {IRenderInfo}
         */
        render: function(scene, camera, notUpdateScene, preZ) {
            var _gl = this.gl;

            var clearColor = this.clearColor;

            Eif (this.clearBit) {

                // Must set depth and color mask true before clear
                _gl.colorMask(true, true, true, true);
                _gl.depthMask(true);
                var viewport = this.viewport;
                var needsScissor = false;
                var viewportDpr = viewport.devicePixelRatio;
                if (viewport.width !== this._width || viewport.height !== this._height
                    || (viewportDpr && viewportDpr !== this.devicePixelRatio)
                    || viewport.x || viewport.y
                ) {
                    needsScissor = true;
                    // http://stackoverflow.com/questions/11544608/how-to-clear-a-rectangle-area-in-webgl
                    // Only clear the viewport
                    _gl.enable(_gl.SCISSOR_TEST);
                    _gl.scissor(viewport.x * viewportDpr, viewport.y * viewportDpr, viewport.width * viewportDpr, viewport.height * viewportDpr);
                }
                _gl.clearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
                _gl.clear(this.clearBit);
                if (needsScissor) {
                    _gl.disable(_gl.SCISSOR_TEST);
                }
            }

            // If the scene have been updated in the prepass like shadow map
            // There is no need to update it again
            if (!notUpdateScene) {
                scene.update(false);
            }
            scene.updateLights();

            camera = camera || scene.getMainCamera();
            Iif (!camera) {
                console.error('Can\'t find camera in the scene.');
                return;
            }
            camera.update();
            var renderList = scene.updateRenderList(camera);

            this._sceneRendering = scene;

            var opaqueList = renderList.opaque;
            var transparentList = renderList.transparent;
            var sceneMaterial = scene.material;

            scene.trigger('beforerender', this, scene, camera, renderList);

            // Render pre z
            Iif (preZ) {
                this.renderPreZ(opaqueList, scene, camera);
                _gl.depthFunc(_gl.LEQUAL);
            }
            else {
                _gl.depthFunc(_gl.LESS);
            }

            // Update the depth of transparent list.
            var worldViewMat = mat4Create();
            var posViewSpace = vec3.create();
            for (var i = 0; i < transparentList.length; i++) {
                var renderable = transparentList[i];
                mat4.multiplyAffine(worldViewMat, camera.viewMatrix.array, renderable.worldTransform.array);
                vec3.transformMat4(posViewSpace, renderable.position.array, worldViewMat);
                renderable.__depth = posViewSpace[2];
            }

            // Render opaque list
            this.renderPass(opaqueList, camera, {
                getMaterial: function (renderable) {
                    return sceneMaterial || renderable.material;
                },
                sortCompare: this.opaqueSortCompare
            });

            this.renderPass(transparentList, camera, {
                getMaterial: function (renderable) {
                    return sceneMaterial || renderable.material;
                },
                sortCompare: this.transparentSortCompare
            });

            scene.trigger('afterrender', this, scene, camera, renderList);

            // Cleanup
            this._sceneRendering = null;
        },

        getProgram: function (renderable, renderMaterial, scene) {
            renderMaterial = renderMaterial || renderable.material;
            return this._programMgr.getProgram(renderable, renderMaterial, scene);
        },

        validateProgram: function (program) {
            Iif (program.__error) {
                var errorMsg = program.__error;
                if (errorShader[program.__uid__]) {
                    return;
                }
                errorShader[program.__uid__] = true;

                if (this.throwError) {
                    throw new Error(errorMsg);
                }
                else {
                    this.trigger('error', errorMsg);
                }
            }

        },

        updatePrograms: function (list, scene, passConfig) {
            var getMaterial = (passConfig && passConfig.getMaterial) || defaultGetMaterial;
            scene = scene || null;
            for (var i = 0; i < list.length; i++) {
                var renderable = list[i];
                var renderMaterial = getMaterial.call(this, renderable);
                if (i > 0) {
                    var prevRenderable = list[i - 1];
                    var prevJointsLen = prevRenderable.joints ? prevRenderable.joints.length : 0;
                    var jointsLen = renderable.joints ? renderable.joints.length : 0;
                    // Keep program not change if joints, material, lightGroup are same of two renderables.
                    Iif (jointsLen === prevJointsLen
                        && renderable.material === prevRenderable.material
                        && renderable.lightGroup === prevRenderable.lightGroup
                    ) {
                        renderable.__program = prevRenderable.__program;
                        continue;
                    }
                }

                var program = this._programMgr.getProgram(renderable, renderMaterial, scene);

                this.validateProgram(program);

                renderable.__program = program;
            }
        },

        /**
         * Render a single renderable list in camera in sequence
         * @param {clay.Renderable[]} list List of all renderables.
         * @param {clay.Camera} camera
         * @param {Object} [passConfig]
         * @param {Function} [passConfig.getMaterial] Get renderable material.
         * @param {Function} [passConfig.beforeRender] Before render each renderable.
         * @param {Function} [passConfig.afterRender] After render each renderable
         * @param {Function} [passConfig.ifRender] If render the renderable.
         * @param {Function} [passConfig.sortCompare] Sort compare function.
         * @return {IRenderInfo}
         */
        renderPass: function(list, camera, passConfig) {
            this.trigger('beforerenderpass', this, list, camera, passConfig);

            passConfig = passConfig || {};
            passConfig.getMaterial = passConfig.getMaterial || defaultGetMaterial;
            passConfig.beforeRender = passConfig.beforeRender || noop;
            passConfig.afterRender = passConfig.afterRender || noop;

            this.updatePrograms(list, this._sceneRendering, passConfig);
            if (passConfig.sortCompare) {
                list.sort(passConfig.sortCompare);
            }

            // Some common builtin uniforms
            var viewport = this.viewport;
            var vDpr = viewport.devicePixelRatio;
            var viewportUniform = [
                viewport.x * vDpr, viewport.y * vDpr,
                viewport.width * vDpr, viewport.height * vDpr
            ];
            var windowDpr = this.devicePixelRatio;
            var windowSizeUniform = this.__currentFrameBuffer
                ? [this.__currentFrameBuffer.getTextureWidth(), this.__currentFrameBuffer.getTextureHeight()]
                : [this._width * windowDpr, this._height * windowDpr];
            // DEPRECATED
            var viewportSizeUniform = [
                viewportUniform[2], viewportUniform[3]
            ];
            var time = Date.now();

            // Calculate view and projection matrix
            mat4.copy(matrices.VIEW, camera.viewMatrix.array);
            mat4.copy(matrices.PROJECTION, camera.projectionMatrix.array);
            mat4.multiply(matrices.VIEWPROJECTION, camera.projectionMatrix.array, matrices.VIEW);
            mat4.copy(matrices.VIEWINVERSE, camera.worldTransform.array);
            mat4.invert(matrices.PROJECTIONINVERSE, matrices.PROJECTION);
            mat4.invert(matrices.VIEWPROJECTIONINVERSE, matrices.VIEWPROJECTION);

            var _gl = this.gl;
            var scene = this._sceneRendering;

            var prevMaterial;
            var prevProgram;

            // Status
            var depthTest, depthMask;
            var culling, cullFace, frontFace;
            var transparent;
            var drawID;
            var currentVAO;

            var vaoExt = this.getGLExtension('OES_vertex_array_object');

            for (var i = 0; i < list.length; i++) {
                var renderable = list[i];
                Iif (passConfig.ifRender && !passConfig.ifRender(renderable)) {
                    continue;
                }

                // Skinned mesh will transformed to joint space. Ignore the mesh transform
                var worldM = renderable.isSkinnedMesh() ? matrices.IDENTITY : renderable.worldTransform.array;
                var geometry = renderable.geometry;
                var material = passConfig.getMaterial.call(this, renderable);

                var program = renderable.__program;
                var shader = material.shader;

                var currentDrawID = geometry.__uid__ + '-' + program.__uid__;
                var drawIDChanged = currentDrawID !== drawID;
                drawID = currentDrawID;
                if (drawIDChanged && vaoExt) {
                    // TODO Seems need to be bound to null immediately (or before bind another program?) if vao is changed
                    vaoExt.bindVertexArrayOES(null);
                }

                mat4.copy(matrices.WORLD, worldM);
                mat4.multiply(matrices.WORLDVIEWPROJECTION, matrices.VIEWPROJECTION, worldM);
                mat4.multiplyAffine(matrices.WORLDVIEW, camera.viewMatrix.array, worldM);
                if (shader.matrixSemantics.WORLDINVERSE ||
                    shader.matrixSemantics.WORLDINVERSETRANSPOSE) {
                    mat4.invert(matrices.WORLDINVERSE, worldM);
                }
                Iif (shader.matrixSemantics.WORLDVIEWINVERSE ||
                    shader.matrixSemantics.WORLDVIEWINVERSETRANSPOSE) {
                    mat4.invert(matrices.WORLDVIEWINVERSE, matrices.WORLDVIEW);
                }
                Iif (shader.matrixSemantics.WORLDVIEWPROJECTIONINVERSE ||
                    shader.matrixSemantics.WORLDVIEWPROJECTIONINVERSETRANSPOSE) {
                    mat4.invert(matrices.WORLDVIEWPROJECTIONINVERSE, matrices.WORLDVIEWPROJECTION);
                }

                // Before render hook
                renderable.beforeRender(this);
                passConfig.beforeRender.call(this, renderable, material, prevMaterial);

                var programChanged = program !== prevProgram;
                if (programChanged) {
                    // Set lights number
                    program.bind(this);
                    // Set some common uniforms
                    program.setUniformOfSemantic(_gl, 'VIEWPORT', viewportUniform);
                    program.setUniformOfSemantic(_gl, 'WINDOW_SIZE', windowSizeUniform);
                    program.setUniformOfSemantic(_gl, 'NEAR', camera.near);
                    program.setUniformOfSemantic(_gl, 'FAR', camera.far);
                    program.setUniformOfSemantic(_gl, 'DEVICEPIXELRATIO', vDpr);
                    program.setUniformOfSemantic(_gl, 'TIME', time);
                    // DEPRECATED
                    program.setUniformOfSemantic(_gl, 'VIEWPORT_SIZE', viewportSizeUniform);

                    // Set lights uniforms
                    // TODO needs optimized
                    if (scene) {
                        scene.setLightUniforms(program, renderable.lightGroup, this);
                    }
                }
                else {
                    program = prevProgram;
                }

                // Program changes also needs reset the materials.
                if (prevMaterial !== material || programChanged) {
                    if (material.depthTest !== depthTest) {
                        material.depthTest ? _gl.enable(_gl.DEPTH_TEST) : _gl.disable(_gl.DEPTH_TEST);
                        depthTest = material.depthTest;
                    }
                    if (material.depthMask !== depthMask) {
                        _gl.depthMask(material.depthMask);
                        depthMask = material.depthMask;
                    }
                    if (material.transparent !== transparent) {
                        material.transparent ? _gl.enable(_gl.BLEND) : _gl.disable(_gl.BLEND);
                        transparent = material.transparent;
                    }
                    // TODO cache blending
                    Iif (material.transparent) {
                        if (material.blend) {
                            material.blend(_gl);
                        }
                        else {
                            // Default blend function
                            _gl.blendEquationSeparate(_gl.FUNC_ADD, _gl.FUNC_ADD);
                            _gl.blendFuncSeparate(_gl.SRC_ALPHA, _gl.ONE_MINUS_SRC_ALPHA, _gl.ONE, _gl.ONE_MINUS_SRC_ALPHA);
                        }
                    }

                    this._bindMaterial(material, program, prevMaterial || null, prevProgram || null);
                    prevMaterial = material;
                }

                var matrixSemanticKeys = shader.matrixSemanticKeys;
                for (var k = 0; k < matrixSemanticKeys.length; k++) {
                    var semantic = matrixSemanticKeys[k];
                    var semanticInfo = shader.matrixSemantics[semantic];
                    var matrix = matrices[semantic];
                    if (semanticInfo.isTranspose) {
                        var matrixNoTranspose = matrices[semanticInfo.semanticNoTranspose];
                        mat4.transpose(matrix, matrixNoTranspose);
                    }
                    program.setUniform(_gl, semanticInfo.type, semanticInfo.symbol, matrix);
                }

                if (renderable.cullFace !== cullFace) {
                    cullFace = renderable.cullFace;
                    _gl.cullFace(cullFace);
                }
                if (renderable.frontFace !== frontFace) {
                    frontFace = renderable.frontFace;
                    _gl.frontFace(frontFace);
                }
                if (renderable.culling !== culling) {
                    culling = renderable.culling;
                    culling ? _gl.enable(_gl.CULL_FACE) : _gl.disable(_gl.CULL_FACE);
                }

                this._updateSkeleton(renderable, program);
                if (drawIDChanged) {
                    currentVAO = this._bindVAO(vaoExt, shader, geometry, program);
                }
                this._renderObject(renderable, currentVAO);

                // After render hook
                passConfig.afterRender.call(this, renderable);
                renderable.afterRender(this);

                prevProgram = program;
            }

            // TODO Seems need to be bound to null immediately if vao is changed?
            Eif (vaoExt) {
                vaoExt.bindVertexArrayOES(null);
            }

            this.trigger('afterrenderpass', this, list, camera, passConfig);
        },

        _updateSkeleton: function (object, program) {
            var _gl = this.gl;
            // Set pose matrices of skinned mesh
            Iif (object.skeleton) {
                object.skeleton.update();
                var skinMatricesArray = object.skeleton.getSubSkinMatrices(object.__uid__, object.joints);
                program.setUniformOfSemantic(_gl, 'SKIN_MATRIX', skinMatricesArray);
            }
        },

        _renderObject: function (renderable, vao) {
            var _gl = this.gl;
            var geometry = renderable.geometry;

            var glDrawMode = renderable.mode;

            Iif (glDrawMode === glenum.LINES || glDrawMode === glenum.LINE_STRIP || glDrawMode === glenum.LINE_LOOP) {
                _gl.lineWidth(this.lineWidth);
            }

            Eif (vao.indicesBuffer) {
                var uintExt = this.getGLExtension('OES_element_index_uint');
                var useUintExt = uintExt && (geometry.indices instanceof Uint32Array);
                var indicesType = useUintExt ? _gl.UNSIGNED_INT : _gl.UNSIGNED_SHORT;

                _gl.drawElements(glDrawMode, vao.indicesBuffer.count, indicesType, 0);
            }
            else {
                // FIXME Use vertex number in buffer
                // vertexCount may get the wrong value when geometry forget to mark dirty after update
                _gl.drawArrays(glDrawMode, 0, geometry.vertexCount);
            }
        },

        _bindMaterial: function (material, program, prevMaterial, prevProgram) {
            var _gl = this.gl;
            // PENDING Same texture in different material take different slot?

            // May use shader of other material if shader code are same
            var sameProgram = prevProgram === program;

            var currentTextureSlot = program.currentTextureSlot();
            var enabledUniforms = material.getEnabledUniforms();
            var textureUniforms = material.getTextureUniforms();

            for (var u = 0; u < textureUniforms.length; u++) {
                var symbol = textureUniforms[u];
                var uniformValue = material.uniforms[symbol].value;
                var uniformType = material.uniforms[symbol].type;
                // Not use `instanceof` to determine if a value is texture in Material#bind.
                // Use type instead, in some case texture may be in different namespaces.
                // TODO Duck type validate.
                if (uniformType === 't' && uniformValue) {
                    // Reset slot
                    uniformValue.__slot = -1;
                }
                else Iif (uniformType === 'tv') {
                    for (var i = 0; i < uniformValue.length; i++) {
                        if (uniformValue[i] instanceof Texture) {
                            uniformValue[i].__slot = -1;
                        }
                    }
                }
            }

            // Set uniforms
            for (var u = 0; u < enabledUniforms.length; u++) {
                var symbol = enabledUniforms[u];
                var uniform = material.uniforms[symbol];
                var uniformValue = uniform.value;
                // PENDING
                // When binding two materials with the same shader
                // Many uniforms will be be set twice even if they have the same value
                // So add a evaluation to see if the uniform is really needed to be set
                if (prevMaterial && sameProgram) {
                    if (prevMaterial.uniforms[symbol].value === uniformValue) {
                        continue;
                    }
                }
                var uniformType = uniform.type;

                if (uniformValue === null) {
                    // FIXME Assume material with same shader have same order uniforms
                    // Or if different material use same textures,
                    // the slot will be different and still skipped because optimization
                    Eif (uniform.type === 't') {
                        var slot = program.currentTextureSlot();
                        var res = program.setUniform(_gl, '1i', symbol, slot);
                        Iif (res) { // Texture is enabled
                            // Still occupy the slot to make sure same texture in different materials have same slot.
                            program.takeCurrentTextureSlot(this, null);
                        }
                    }
                    continue;
                }
                else if (uniformType === 't') {
                    Eif (uniformValue.__slot < 0) {
                        var slot = program.currentTextureSlot();
                        var res = program.setUniform(_gl, '1i', symbol, slot);
                        Iif (!res) { // Texture uniform is not enabled
                            continue;
                        }
                        program.takeCurrentTextureSlot(this, uniformValue);
                        uniformValue.__slot = slot;
                    }
                    // Multiple uniform use same texture..
                    else {
                        program.setUniform(_gl, '1i', symbol, uniformValue.__slot);
                    }
                }
                else if (Array.isArray(uniformValue)) {
                    if (uniformValue.length === 0) {
                        continue;
                    }
                    // Texture Array
                    Iif (uniformType === 'tv') {
                        if (!program.hasUniform(symbol)) {
                            continue;
                        }

                        var arr = [];
                        for (var i = 0; i < uniformValue.length; i++) {
                            var texture = uniformValue[i];

                            if (texture.__slot < 0) {
                                var slot = program.currentTextureSlot();
                                arr.push(slot);
                                program.takeCurrentTextureSlot(this, texture);
                                texture.__slot = slot;
                            }
                            else {
                                arr.push(texture.__slot);
                            }
                        }

                        program.setUniform(_gl, '1iv', symbol, arr);
                    }
                    else {
                        program.setUniform(_gl, uniform.type, symbol, uniformValue);
                    }
                }
                else{
                    program.setUniform(_gl, uniform.type, symbol, uniformValue);
                }
            }
            // Texture slot maybe used out of material.
            program.resetTextureSlot(currentTextureSlot);
        },

        _bindVAO: function (vaoExt, shader, geometry, program) {
            var isStatic = !geometry.dynamic;
            var _gl = this.gl;

            var vaoId = this.__uid__ + '-' + program.__uid__;
            var vao = geometry.__vaoCache[vaoId];
            if (!vao) {
                var chunks = geometry.getBufferChunks(this);
                Iif (!chunks || !chunks.length) {  // Empty mesh
                    return;
                }
                var chunk = chunks[0];
                var attributeBuffers = chunk.attributeBuffers;
                var indicesBuffer = chunk.indicesBuffer;

                var availableAttributes = [];
                var availableAttributeSymbols = [];
                for (var a = 0; a < attributeBuffers.length; a++) {
                    var attributeBufferInfo = attributeBuffers[a];
                    var name = attributeBufferInfo.name;
                    var semantic = attributeBufferInfo.semantic;
                    var symbol;
                    Eif (semantic) {
                        var semanticInfo = shader.attributeSemantics[semantic];
                        symbol = semanticInfo && semanticInfo.symbol;
                    }
                    else {
                        symbol = name;
                    }
                    if (symbol && program.attributes[symbol]) {
                        availableAttributes.push(attributeBufferInfo);
                        availableAttributeSymbols.push(symbol);
                    }
                }

                vao = new VertexArrayObject(
                    availableAttributes,
                    availableAttributeSymbols,
                    indicesBuffer
                );

                Eif (isStatic) {
                    geometry.__vaoCache[vaoId] = vao;
                }
            }

            var needsBindAttributes = true;

            // Create vertex object array cost a lot
            // So we don't use it on the dynamic object
            Eif (vaoExt && isStatic) {
                // Use vertex array object
                // http://blog.tojicode.com/2012/10/oesvertexarrayobject-extension.html
                if (vao.vao == null) {
                    vao.vao = vaoExt.createVertexArrayOES();
                }
                else {
                    needsBindAttributes = false;
                }
                vaoExt.bindVertexArrayOES(vao.vao);
            }

            var availableAttributes = vao.availableAttributes;
            var indicesBuffer = vao.indicesBuffer;

            if (needsBindAttributes) {
                var locationList = program.enableAttributes(this, vao.availableAttributeSymbols, (vaoExt && isStatic && vao));
                // Setting attributes;
                for (var a = 0; a < availableAttributes.length; a++) {
                    var location = locationList[a];
                    if (location === -1) {
                        continue;
                    }
                    var attributeBufferInfo = availableAttributes[a];
                    var buffer = attributeBufferInfo.buffer;
                    var size = attributeBufferInfo.size;
                    var glType = attributeBufferTypeMap[attributeBufferInfo.type] || _gl.FLOAT;

                    _gl.bindBuffer(_gl.ARRAY_BUFFER, buffer);
                    _gl.vertexAttribPointer(location, size, glType, false, 0, 0);
                }

                Eif (geometry.isUseIndices()) {
                    _gl.bindBuffer(_gl.ELEMENT_ARRAY_BUFFER, indicesBuffer.buffer);
                }
            }

            return vao;
        },

        renderPreZ: function (list, scene, camera) {
            var _gl = this.gl;
            var preZPassMaterial = this._prezMaterial || new Material({
                shader: new Shader(Shader.source('clay.prez.vertex'), Shader.source('clay.prez.fragment'))
            });
            this._prezMaterial = preZPassMaterial;

            _gl.colorMask(false, false, false, false);
            _gl.depthMask(true);

            // Status
            this.renderPass(list, camera, {
                ifRender: function (renderable) {
                    return !renderable.ignorePreZ;
                },
                getMaterial: function () {
                    return preZPassMaterial;
                },
                sort: this.opaqueSortCompare
            });

            _gl.colorMask(true, true, true, true);
            _gl.depthMask(true);
        },

        /**
         * Dispose given scene, including all geometris, textures and shaders in the scene
         * @param {clay.Scene} scene
         */
        disposeScene: function(scene) {
            this.disposeNode(scene, true, true);
            scene.dispose();
        },

        /**
         * Dispose given node, including all geometries, textures and shaders attached on it or its descendant
         * @param {clay.Node} node
         * @param {boolean} [disposeGeometry=false] If dispose the geometries used in the descendant mesh
         * @param {boolean} [disposeTexture=false] If dispose the textures used in the descendant mesh
         */
        disposeNode: function(root, disposeGeometry, disposeTexture) {
            // Dettached from parent
            if (root.getParent()) {
                root.getParent().remove(root);
            }
            var disposedMap = {};
            root.traverse(function(node) {
                var material = node.material;
                if (node.geometry && disposeGeometry) {
                    node.geometry.dispose(this);
                }
                if (disposeTexture && material && !disposedMap[material.__uid__]) {
                    var textureUniforms = material.getTextureUniforms();
                    for (var u = 0; u < textureUniforms.length; u++) {
                        var uniformName = textureUniforms[u];
                        var val = material.uniforms[uniformName].value;
                        var uniformType = material.uniforms[uniformName].type;
                        if (!val) {
                            continue;
                        }
                        if (uniformType === 't') {
                            val.dispose && val.dispose(this);
                        }
                        else if (uniformType === 'tv') {
                            for (var k = 0; k < val.length; k++) {
                                if (val[k]) {
                                    val[k].dispose && val[k].dispose(this);
                                }
                            }
                        }
                    }
                    disposedMap[material.__uid__] = true;
                }
                // Particle system and AmbientCubemap light need to dispose
                if (node.dispose) {
                    node.dispose(this);
                }
            }, this);
        },

        /**
         * Dispose given geometry
         * @param {clay.Geometry} geometry
         */
        disposeGeometry: function(geometry) {
            geometry.dispose(this);
        },

        /**
         * Dispose given texture
         * @param {clay.Texture} texture
         */
        disposeTexture: function(texture) {
            texture.dispose(this);
        },

        /**
         * Dispose given frame buffer
         * @param {clay.FrameBuffer} frameBuffer
         */
        disposeFrameBuffer: function(frameBuffer) {
            frameBuffer.dispose(this);
        },

        /**
         * Dispose renderer
         */
        dispose: function () {},

        /**
         * Convert screen coords to normalized device coordinates(NDC)
         * Screen coords can get from mouse event, it is positioned relative to canvas element
         * NDC can be used in ray casting with Camera.prototype.castRay methods
         *
         * @param  {number}       x
         * @param  {number}       y
         * @param  {clay.Vector2} [out]
         * @return {clay.Vector2}
         */
        screenToNDC: function(x, y, out) {
            if (!out) {
                out = new Vector2();
            }
            // Invert y;
            y = this._height - y;

            var viewport = this.viewport;
            var arr = out.array;
            arr[0] = (x - viewport.x) / viewport.width;
            arr[0] = arr[0] * 2 - 1;
            arr[1] = (y - viewport.y) / viewport.height;
            arr[1] = arr[1] * 2 - 1;

            return out;
        }
    });

    /**
     * Opaque renderables compare function
     * @param  {clay.Renderable} x
     * @param  {clay.Renderable} y
     * @return {boolean}
     * @static
     */
    Renderer.opaqueSortCompare = Renderer.prototype.opaqueSortCompare = function(x, y) {
        // Priority renderOrder -> program -> material -> geometry
        Eif (x.renderOrder === y.renderOrder) {
            Eif (x.__program === y.__program) {
                Iif (x.material === y.material) {
                    return x.geometry.__uid__ - y.geometry.__uid__;
                }
                return x.material.__uid__ - y.material.__uid__;
            }
            if (x.__program && y.__program) {
                return x.__program.__uid__ - y.__program.__uid__;
            }
            return 0;
        }
        return x.renderOrder - y.renderOrder;
    };

    /**
     * Transparent renderables compare function
     * @param  {clay.Renderable} a
     * @param  {clay.Renderable} b
     * @return {boolean}
     * @static
     */
    Renderer.transparentSortCompare = Renderer.prototype.transparentSortCompare = function(x, y) {
        // Priority renderOrder -> depth -> program -> material -> geometry

        if (x.renderOrder === y.renderOrder) {
            if (x.__depth === y.__depth) {
                if (x.__program === y.__program) {
                    if (x.material === y.material) {
                        return x.geometry.__uid__ - y.geometry.__uid__;
                    }
                    return x.material.__uid__ - y.material.__uid__;
                }
                if (x.__program  && y.__program) {
                    return x.__program.__uid__ - y.__program.__uid__;
                }
                return 0;
            }
            // Depth is negative
            // So farther object has smaller depth value
            return x.__depth - y.__depth;
        }
        return x.renderOrder - y.renderOrder;
    };

    // Temporary variables
    var matrices = {
        IDENTITY: mat4Create(),

        WORLD: mat4Create(),
        VIEW: mat4Create(),
        PROJECTION: mat4Create(),
        WORLDVIEW: mat4Create(),
        VIEWPROJECTION: mat4Create(),
        WORLDVIEWPROJECTION: mat4Create(),

        WORLDINVERSE: mat4Create(),
        VIEWINVERSE: mat4Create(),
        PROJECTIONINVERSE: mat4Create(),
        WORLDVIEWINVERSE: mat4Create(),
        VIEWPROJECTIONINVERSE: mat4Create(),
        WORLDVIEWPROJECTIONINVERSE: mat4Create(),

        WORLDTRANSPOSE: mat4Create(),
        VIEWTRANSPOSE: mat4Create(),
        PROJECTIONTRANSPOSE: mat4Create(),
        WORLDVIEWTRANSPOSE: mat4Create(),
        VIEWPROJECTIONTRANSPOSE: mat4Create(),
        WORLDVIEWPROJECTIONTRANSPOSE: mat4Create(),
        WORLDINVERSETRANSPOSE: mat4Create(),
        VIEWINVERSETRANSPOSE: mat4Create(),
        PROJECTIONINVERSETRANSPOSE: mat4Create(),
        WORLDVIEWINVERSETRANSPOSE: mat4Create(),
        VIEWPROJECTIONINVERSETRANSPOSE: mat4Create(),
        WORLDVIEWPROJECTIONINVERSETRANSPOSE: mat4Create()
    };

    /**
     * @name clay.Renderer.COLOR_BUFFER_BIT
     * @type {number}
     */
    Renderer.COLOR_BUFFER_BIT = glenum.COLOR_BUFFER_BIT;
    /**
     * @name clay.Renderer.DEPTH_BUFFER_BIT
     * @type {number}
     */
    Renderer.DEPTH_BUFFER_BIT = glenum.DEPTH_BUFFER_BIT;
    /**
     * @name clay.Renderer.STENCIL_BUFFER_BIT
     * @type {number}
     */
    Renderer.STENCIL_BUFFER_BIT = glenum.STENCIL_BUFFER_BIT;

    export default Renderer;