sawine@73: function main()
sawine@73: {
sawine@73:     var canvas = document.getElementById("machine");
sawine@73:     var context = new Context(canvas);
sawine@73:     var gl = context.gl;
sawine@73:     context.object = new Box(1, context);
sawine@73:     gl.clearColor(0.0, 0.0, 0.0, 1.0);
sawine@73:     gl.enable(gl.DEPTH_TEST);
sawine@73:     draw(context);
sawine@73: }
sawine@73: 
sawine@73: function Context(canvas)
sawine@73: {
sawine@73:     try 
sawine@73:     {
sawine@73: 	this.gl = canvas.getContext("experimental-webgl");
sawine@73: 	this.viewport = {'width': canvas.width,
sawine@73: 			 'height': canvas.height};
sawine@73:     } 
sawine@73:     catch(e) 
sawine@73:     {
sawine@73: 	alert(e);
sawine@73:     }
sawine@73:     if (!this.gl) alert("Failed: WebGL init.");
sawine@73:     this.mvMatrix = mat4.create();
sawine@73:     this.pMatrix = mat4.create();
sawine@73:     this.shader = new Shader(this);    
sawine@73: }
sawine@73: Context.prototype.updateMatrixUniforms = function()
sawine@73: {
sawine@73:     var gl = this.gl;
sawine@73:     var program = this.shader.program;
sawine@73:     var pMatrix = this.pMatrix;
sawine@73:     var mvMatrix = this.mvMatrix;
sawine@73:     gl.uniformMatrix4fv(program.pMatrixUniform, false, pMatrix);
sawine@73:     gl.uniformMatrix4fv(program.mvMatrixUniform, false, mvMatrix);
sawine@73: }
sawine@73: 
sawine@73: function Shader(context)
sawine@73: {
sawine@73:     var gl = context.gl;
sawine@73:     var fragment = loadShader(gl, "shader-fs");
sawine@73:     var vertex = loadShader(gl, "shader-vs");
sawine@73:     this.program = gl.createProgram();
sawine@73:     gl.attachShader(this.program, vertex);
sawine@73:     gl.attachShader(this.program, fragment);
sawine@73:     gl.linkProgram(this.program);
sawine@73: 
sawine@73:     if (!gl.getProgramParameter(this.program, gl.LINK_STATUS))
sawine@73:     {
sawine@73: 	alert("Failed: Shader init.");
sawine@73:     }
sawine@73: 
sawine@73:     gl.useProgram(this.program);
sawine@73:     this.vertexPosition = gl.getAttribLocation(this.program, "aVertexPosition");
sawine@73:     gl.enableVertexAttribArray(this.vertexPosition);
sawine@73:     this.pMatrixUniform = gl.getUniformLocation(this.program, "uPMatrix");
sawine@73:     this.mvMatrixUniform = gl.getUniformLocation(this.program, "uMVMatrix");
sawine@73: 
sawine@73:     function loadShader(gl, id)
sawine@73:     {
sawine@73: 	var script = document.getElementById(id);
sawine@73: 	if (!script) return null;
sawine@73: 	
sawine@73: 	var str = "";
sawine@73: 	var child = script.firstChild;
sawine@73: 	while (child)
sawine@73: 	{
sawine@73: 	    if (child.nodeType == 3) str += child.textContent;
sawine@73: 	    child = child.nextSibling;
sawine@73: 	}
sawine@73: 	
sawine@73: 	var shader;
sawine@73: 	var common = "x-shader/x-";
sawine@73: 	if (script.type == common + "fragment") shader = gl.createShader(gl.FRAGMENT_SHADER);
sawine@73: 	else if (script.type == common + "vertex") shader = gl.createShader(gl.VERTEX_SHADER);
sawine@73: 	else return null;
sawine@73: 
sawine@73: 	gl.shaderSource(shader, str);
sawine@73: 	gl.compileShader(shader);
sawine@73: 
sawine@73: 	if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS))
sawine@73:         {
sawine@73: 	    alert(gl.getShaderInfoLog(shader));
sawine@73: 	    return null;
sawine@73: 	}
sawine@73: 
sawine@73: 	return shader;
sawine@73:     }
sawine@73: }
sawine@73: 
sawine@73: 
sawine@73: function Box(size, context)
sawine@73: {
sawine@73:     var gl = context.gl;
sawine@73:     this.size = size || 1;
sawine@73:     this.buffer = gl.createBuffer();
sawine@73:     gl.bindBuffer(gl.ARRAY_BUFFER, this.buffer);
sawine@73:     var vertices = [1.0, 1.0, 0.0,
sawine@73: 		    -1.0, 1.0, 0.0,
sawine@73: 		    1.0, -1.0, 0.0,
sawine@73: 		    -1.0, -1.0, 0.0];
sawine@73:     gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
sawine@73:     this.itemSize = 3;
sawine@73:     this.numItems = 4;
sawine@73: }
sawine@73: 
sawine@73: function draw(context)
sawine@73: {
sawine@73:     var gl = context.gl;
sawine@73:     var viewport = context.viewport;
sawine@73:     var shader = context.shader;
sawine@73:     var mvMatrix = context.mvMatrix;
sawine@73:     var pMatrix = context.pMatrix;
sawine@73:     var object = context.object;
sawine@73:     gl.viewport(0, 0, viewport.width, viewport.height);
sawine@73:     gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
sawine@73:     mat4.perspective(45, viewport.width / viewport.height, 0.1, 100.0, pMatrix);
sawine@73:     mat4.identity(mvMatrix);
sawine@73:     mat4.translate(mvMatrix, [0.0, 0.0, -7.0]);
sawine@73:     gl.bindBuffer(gl.ARRAY_BUFFER, object.buffer);
sawine@73:     gl.vertexAttribPointer(shader.vertexPosition, object.itemSize, gl.FLOAT, false, 0, 0); 
sawine@73:     gl.uniformMatrix4fv(shader.pMatrixUniform, false, pMatrix);
sawine@73:     gl.uniformMatrix4fv(shader.mvMatrixUniform, false, mvMatrix);
sawine@73:     //context.updateMatrixUniforms();
sawine@73:     gl.drawArrays(gl.TRIANGLE_STRIP, 0, object.numItems);
sawine@73:     return context;
sawine@73: } 
sawine@73: 
sawine@73: function drawScene(context) {
sawine@73:         gl.viewport(0, 0, viewport.width, viewport.height);
sawine@73:         gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
sawine@73:  
sawine@73:         mat4.perspective(45, viewport.width / viewport.height, 0.1, 100.0, pMatrix);
sawine@73:  
sawine@73:         mat4.identity(mvMatrix); 
sawine@73:         mat4.translate(mvMatrix, [0.0, 0.0, -7.0]);
sawine@73:   
sawine@73:         gl.bindBuffer(gl.ARRAY_BUFFER, object.buffer);
sawine@73:         gl.vertexAttribPointer(shader.vertexPosition, object.itemSize, gl.FLOAT, false, 0, 0);
sawine@73:         gl.uniformMatrix4fv(shader.pMatrixUniform, false, pMatrix);
sawine@73: 	gl.uniformMatrix4fv(shader.mvMatrixUniform, false, mvMatrix);
sawine@73:         gl.drawArrays(gl.TRIANGLE_STRIP, 0, object.numItems);
sawine@73:     }
sawine@73: