ref: af1bec840492f50128b60546b3cf06bc202214a2
parent: 93218e30ee1318532ff85a6111c97aa231cd0a0c
author: Sam Leitch <sam@luceva.net>
date: Tue Feb 18 17:25:10 EST 2014
Started simplifying the YUVCanvas. Still not complete
--- /dev/null
+++ b/js/yuvCanvas.js
@@ -1,0 +1,236 @@
+//
+// Copyright (c) 2014 Sam Leitch. All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+// TODO: Incorporate cropping information
+
+/**
+ * This class grabs content from a video element and feeds it to a canvas element.
+ * The content is modified using a custom WebGL shader program.
+ */
+function YUVCanvas(canvas) {+ this.canvasElement = canvas;
+ this.initGlContext();
+
+ if(this.glContext) {+ this.initProgram();
+ this.initBuffers();
+ this.initTextures();
+ } else {+ // TODO: Fill in the non-WebGL initialization here.
+ }
+}
+
+/**
+ * Create the GL context from the canvas element
+ */
+YUVCanvas.prototype.initGlContext = function() {+ var canvas = this.canvasElement;
+ var gl = null;
+
+ var validContextNames = ["webgl", "experimental-webgl", "moz-webgl", "webkit-3d"];
+ var i = 0;
+
+ while(!gl && nameIndex < validNames.length) {+ var contextName = validContextNames[i];
+
+ try {+ gl = canvas.getContext(contextName);
+ } catch (e) {+ gl = null;
+ }
+
+ if(!gl || typeof gl.getParameter !== "function") {+ gl = null;
+ }
+
+ ++i;
+ }
+
+ this.glContext = gl;
+}
+
+/**
+ * Initialize GL shader program
+ */
+YUVCanvas.prototype.initProgram = function() {+ var gl = this.glContext;
+
+ var vertexShaderScript = [
+ 'attribute vec4 vertexPos;',
+ 'attribute vec4 texturePos;',
+ 'varying vec2 textureCoord;',
+
+ 'void main()',
+ '{',+ 'gl_Position = vertexPos;',
+ 'textureCoord = texturePos.xy;',
+ '}'
+ ].join('\n');+
+ var fragmentShaderScript = [
+ 'precision highp float;',
+ 'varying highp vec2 textureCoord;',
+ 'uniform sampler2D ySampler;',
+ 'uniform sampler2D uSampler;',
+ 'uniform sampler2D vSampler;',
+ 'const mat4 YUV2RGB = mat4',
+ '(',+ '1.1643828125, 0, 1.59602734375, -.87078515625,',
+ '1.1643828125, -.39176171875, -.81296875, .52959375,',
+ '1.1643828125, 2.017234375, 0, -1.081390625,',
+ '0, 0, 0, 1',
+ ');',
+
+ 'void main(void) {',+ 'highp float y = texture2D(ySampler, textureCoord).r;'
+ 'highp float u = texture2D(uSampler, textureCoord).r;'
+ 'highp float v = texture2D(vSampler, textureCoord).r;'
+ 'gl_FragColor = vec4(y, u, v, 1) * YUV2RGB;',
+ '}'
+ ].join('\n');+
+ var vertexShader = gl.createShader(gl.VERTEX_SHADER);
+ gl.shaderSource(vertexShader, vertexShaderScript);
+ gl.compileShader(vertexShader);
+ if(!gl.getShaderParameter(vertexShader, gl.COMPILE_STATUS)) {+ console.log('Vertex shader failed to compile: ' + gl.getShaderInfoLog(vertexShader));+ }
+
+ var fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
+ gl.shaderSource(fragmentShader, fragmentShaderScript);
+ gl.compileShader(fragmentShader);
+ if(!gl.getShaderParameter(fragmentShader, gl.COMPILE_STATUS)) {+ console.log('Fragment shader failed to compile: ' + gl.getShaderInfoLog(fragmentShader));+ }
+
+ var program = gl.createProgram();
+ gl.attachShader(program, vertexShader);
+ gl.attachShader(program, fragmentShader);
+ gl.linkProgram(program);
+ if(!gl.getProgramParameter(program, gl.LINK_STATUS)) {+ console.log('Program failed to compile: ' + gl.getProgramInfoLog(program));+ }
+
+ gl.useProgram(program);
+
+ this.shaderProgram = program;
+}
+
+/**
+ * Initialize vertex buffers and attach to shader program
+ */
+YUVCanvas.prototype.initBuffers = function() {+ var gl = this.glContext;
+ var program = this.shaderProgram;
+
+ var vertexPosBuffer = gl.createBuffer();
+ gl.bindBuffer(gl.ARRAY_BUFFER, vertexPosBuffer);
+ gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([1, 1, -1, 1, 1, -1, -1, -1]), gl.STATIC_DRAW);
+
+ var vertexPosRef = gl.getAttribLocation(program, 'vertexPos');
+ gl.enableVertexAttribArray(vertexPosRef);
+ gl.vertexAttribPointer(vertexPosRef, 2, gl.FLOAT, false, 0, 0);
+
+ var texturePosBuffer = gl.createBuffer();
+ gl.bindBuffer(gl.ARRAY_BUFFER, texturePosBuffer);
+ gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([1, 0, 0, 0, 1, 1, 0, 1]), gl.STATIC_DRAW);
+
+ var texturePosRef = gl.getAttribLocation(program, 'texturePos');
+ gl.enableVertexAttribArray(texturePosRef);
+ gl.vertexAttribPointer(texturePosRef, 2, gl.FLOAT, false, 0, 0);
+}
+
+/**
+ * Initialize GL textures and attach to shader program
+ */
+YUVCanvas.prototype.initTextures = function() {+ var gl = this.glContext;
+ var program = this.shaderProgram;
+
+ var yTextureRef = this.initTexture();
+ var ySamplerRef = gl.getUniformLocation(program, 'ySampler');
+ gl.uniform1i(ySamplerRef, 0);
+ this.yTextureRef = yTextureRef;
+
+ var uTextureRef = this.initTexture();
+ var uSamplerRef = gl.getUniformLocation(program, 'uSampler');
+ gl.uniform1i(uSamplerRef, 1);
+ this.uTextureRef = uTextureRef;
+
+ var vTextureRef = this.initTexture();
+ var vSamplerRef = gl.getUniformLocation(program, 'vSampler');
+ gl.uniform1i(vSamplerRef, 2);
+ this.vTextureRef = vTextureRef;
+}
+
+/**
+ * Create and configure a single texture
+ */
+YUVCanvas.prototype.initTexture = function() {+ var textureRef = gl.createTexture();
+ gl.bindTexture(gl.TEXTURE_2D, textureRef);
+ gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
+ gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
+ gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
+ gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
+ gl.bindTexture(gl.TEXTURE_2D, null);
+
+ return textureRef;
+}
+
+/**
+ * Draw yuvData in the best way possible
+ */
+YUVCanvas.prototype.draw = function(yuvData, size) {+ var gl = this.glContext;
+
+ if(gl) {+ this.drawGl(yuvData, size);
+ } else {+ // TODO: Create a non-WebGL YUV conversion.
+ }
+}
+
+/**
+ * Setup GL viewport and draw the yuvData
+ */
+YUVCanvas.prototype.drawGL = function(yuvData, size) {+ var gl = this.glContext;
+ var yTextureRef = this.yTextureRef;
+ var uTextureRef = this.uTextureRef;
+ var vTextureRef = this.vTextureRef;
+
+ gl.viewport(0, 0, size.w, size.h);
+
+ gl.activeTexture(gl.TEXTURE0);
+ gl.bindTexture(gl.TEXTURE_2D, yTextureRef);
+ gl.texImage2D(gl.TEXTURE_2D, 0, gl.LUMINANCE, size.w, size.h, 0, gl.LUMINANCE, gl.UNSIGNED_BYTE, yuvData);
+
+ gl.activeTexture(gl.TEXTURE1);
+ gl.bindTexture(gl.TEXTURE_2D, uTextureRef);
+ gl.texImage2D(gl.TEXTURE_2D, 0, gl.LUMINANCE, size.w/2, size.h/2, 0, gl.LUMINANCE, gl.UNSIGNED_BYTE, yuvData);
+
+ gl.activeTexture(gl.TEXTURE2);
+ gl.bindTexture(gl.TEXTURE_2D, vTextureRef);
+ gl.texImage2D(gl.TEXTURE_2D, 0, gl.LUMINANCE, size.w/2, size.h/2, 0, gl.LUMINANCE, gl.UNSIGNED_BYTE, yuvData);
+
+ gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
+}