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ShinobiCE/tools/ffmpegToWeb/Player/broadway/canvas/WebGLCanvas.js

261 lines
7.3 KiB
JavaScript

"use strict";
/**
* Generic WebGL backed canvas that sets up: a quad to paint a texture on, appropriate vertex/fragment shaders,
* scene parameters and other things. Specialized versions of this class can be created by overriding several
* initialization methods.
*/
var Script = require('./Script');
var error = require('../utils/error');
var makePerspective = require('../utils/glUtils').makePerspective;
var Matrix = require('sylvester.js').Matrix;
var Class = require('uclass');
var vertexShaderScript = Script.createFromSource("x-shader/x-vertex", `
attribute vec3 aVertexPosition;
attribute vec2 aTextureCoord;
uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;
varying highp vec2 vTextureCoord;
void main(void) {
gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
vTextureCoord = aTextureCoord;
}
`);
var fragmentShaderScript = Script.createFromSource("x-shader/x-fragment", `
precision highp float;
varying highp vec2 vTextureCoord;
uniform sampler2D texture;
void main(void) {
gl_FragColor = texture2D(texture, vTextureCoord);
}
`);
var WebGLCanvas = new Class({
initialize : function(canvas, size, useFrameBuffer) {
this.canvas = canvas;
this.size = size;
this.canvas.width = size.w;
this.canvas.height = size.h;
this.onInitWebGL();
this.onInitShaders();
this.initBuffers();
if (useFrameBuffer)
this.initFramebuffer();
this.onInitTextures();
this.initScene();
},
/**
* Initialize a frame buffer so that we can render off-screen.
*/
initFramebuffer : function() {
var gl = this.gl;
// Create framebuffer object and texture.
this.framebuffer = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, this.framebuffer);
this.framebufferTexture = new Texture(this.gl, this.size, gl.RGBA);
// Create and allocate renderbuffer for depth data.
var renderbuffer = gl.createRenderbuffer();
gl.bindRenderbuffer(gl.RENDERBUFFER, renderbuffer);
gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, this.size.w, this.size.h);
// Attach texture and renderbuffer to the framebuffer.
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, this.framebufferTexture.texture, 0);
gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, renderbuffer);
},
/**
* Initialize vertex and texture coordinate buffers for a plane.
*/
initBuffers : function () {
var tmp;
var gl = this.gl;
// Create vertex position buffer.
this.quadVPBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, this.quadVPBuffer);
tmp = [
1.0, 1.0, 0.0,
-1.0, 1.0, 0.0,
1.0, -1.0, 0.0,
-1.0, -1.0, 0.0];
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(tmp), gl.STATIC_DRAW);
this.quadVPBuffer.itemSize = 3;
this.quadVPBuffer.numItems = 4;
/*
+--------------------+
| -1,1 (1) | 1,1 (0)
| |
| |
| |
| |
| |
| -1,-1 (3) | 1,-1 (2)
+--------------------+
*/
var scaleX = 1.0;
var scaleY = 1.0;
// Create vertex texture coordinate buffer.
this.quadVTCBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, this.quadVTCBuffer);
tmp = [
scaleX, 0.0,
0.0, 0.0,
scaleX, scaleY,
0.0, scaleY,
];
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(tmp), gl.STATIC_DRAW);
},
mvIdentity : function () {
this.mvMatrix = Matrix.I(4);
},
mvMultiply : function(m) {
this.mvMatrix = this.mvMatrix.x(m);
},
mvTranslate : function (m) {
this.mvMultiply(Matrix.Translation($V([m[0], m[1], m[2]])).ensure4x4());
},
setMatrixUniforms : function () {
this.program.setMatrixUniform("uPMatrix", new Float32Array(this.perspectiveMatrix.flatten()));
this.program.setMatrixUniform("uMVMatrix", new Float32Array(this.mvMatrix.flatten()));
},
initScene : function() {
var gl = this.gl;
// Establish the perspective with which we want to view the
// scene. Our field of view is 45 degrees, with a width/height
// ratio of 640:480, and we only want to see objects between 0.1 units
// and 100 units away from the camera.
this.perspectiveMatrix = makePerspective(45, 1, 0.1, 100.0);
// Set the drawing position to the "identity" point, which is
// the center of the scene.
this.mvIdentity();
// Now move the drawing position a bit to where we want to start
// drawing the square.
this.mvTranslate([0.0, 0.0, -2.4]);
// Draw the cube by binding the array buffer to the cube's vertices
// array, setting attributes, and pushing it to GL.
gl.bindBuffer(gl.ARRAY_BUFFER, this.quadVPBuffer);
gl.vertexAttribPointer(this.vertexPositionAttribute, 3, gl.FLOAT, false, 0, 0);
// Set the texture coordinates attribute for the vertices.
gl.bindBuffer(gl.ARRAY_BUFFER, this.quadVTCBuffer);
gl.vertexAttribPointer(this.textureCoordAttribute, 2, gl.FLOAT, false, 0, 0);
this.onInitSceneTextures();
this.setMatrixUniforms();
if (this.framebuffer) {
console.log("Bound Frame Buffer");
gl.bindFramebuffer(gl.FRAMEBUFFER, this.framebuffer);
}
},
toString: function() {
return "WebGLCanvas Size: " + this.size;
},
checkLastError: function (operation) {
var err = this.gl.getError();
if (err != this.gl.NO_ERROR) {
var name = this.glNames[err];
name = (name !== undefined) ? name + "(" + err + ")":
("Unknown WebGL ENUM (0x" + value.toString(16) + ")");
if (operation) {
console.log("WebGL Error: %s, %s", operation, name);
} else {
console.log("WebGL Error: %s", name);
}
console.trace();
}
},
onInitWebGL: function () {
try {
this.gl = this.canvas.getContext("experimental-webgl");
} catch(e) {}
if (!this.gl) {
error("Unable to initialize WebGL. Your browser may not support it.");
}
if (this.glNames) {
return;
}
this.glNames = {};
for (var propertyName in this.gl) {
if (typeof this.gl[propertyName] == 'number') {
this.glNames[this.gl[propertyName]] = propertyName;
}
}
},
onInitShaders: function() {
this.program = new Program(this.gl);
this.program.attach(new Shader(this.gl, vertexShaderScript));
this.program.attach(new Shader(this.gl, fragmentShaderScript));
this.program.link();
this.program.use();
this.vertexPositionAttribute = this.program.getAttributeLocation("aVertexPosition");
this.gl.enableVertexAttribArray(this.vertexPositionAttribute);
this.textureCoordAttribute = this.program.getAttributeLocation("aTextureCoord");;
this.gl.enableVertexAttribArray(this.textureCoordAttribute);
},
onInitTextures: function () {
var gl = this.gl;
this.texture = new Texture(gl, this.size, gl.RGBA);
},
onInitSceneTextures: function () {
this.texture.bind(0, this.program, "texture");
},
drawScene: function() {
this.gl.drawArrays(this.gl.TRIANGLE_STRIP, 0, 4);
},
readPixels: function(buffer) {
var gl = this.gl;
gl.readPixels(0, 0, this.size.w, this.size.h, gl.RGBA, gl.UNSIGNED_BYTE, buffer);
},
});
module.exports = WebGLCanvas;