I am having a look at web gl, and trying to render a cube, but I am having a problem when I try to add projection into the vertex shader. I have added an attribute, but when I use it to multiple the modelview and position, it stops displaying the cube. Im not sure why and was wondering if anyone could help? Ive tried looking at a few examples but just cant get this to work vertex shader attribute vec3 aVertexPosition; uniform mat4 uMVMatrix; uniform mat4 uPMatrix; void main(void) { gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0); //gl_Position = uMVMatrix * vec4(aVertexPosition, 1.0); } fragment shader #ifdef GL_ES precision highp float; // Not sure why this is required, need to google it #endif uniform vec4 uColor; void main() { gl_FragColor = uColor; } function init() { // Get a reference to our drawing surface canvas = document.getElementById("webglSurface"); gl = canvas.getContext("experimental-webgl"); /** Create our simple program **/ // Get our shaders var v = document.getElementById("vertexShader").firstChild.nodeValue; var f = document.getElementById("fragmentShader").firstChild.nodeValue; // Compile vertex shader var vs = gl.createShader(gl.VERTEX_SHADER); gl.shaderSource(vs, v); gl.compileShader(vs); // Compile fragment shader var fs = gl.createShader(gl.FRAGMENT_SHADER); gl.shaderSource(fs, f); gl.compileShader(fs); // Create program and attach shaders program = gl.createProgram(); gl.attachShader(program, vs); gl.attachShader(program, fs); gl.linkProgram(program); // Some debug code to check for shader compile errors and log them to console if (!gl.getShaderParameter(vs, gl.COMPILE_STATUS)) console.log(gl.getShaderInfoLog(vs)); if (!gl.getShaderParameter(fs, gl.COMPILE_STATUS)) console.log(gl.getShaderInfoLog(fs)); if (!gl.getProgramParameter(program, gl.LINK_STATUS)) console.log(gl.getProgramInfoLog(program)); /* Create some simple VBOs*/ // Vertices for a cube var vertices = new Float32Array([ -0.5, 0.5, 0.5, // 0 -0.5, -0.5, 0.5, // 1 0.5, 0.5, 0.5, // 2 0.5, -0.5, 0.5, // 3 -0.5, 0.5, -0.5, // 4 -0.5, -0.5, -0.5, // 5 -0.5, 0.5, -0.5, // 6 -0.5,-0.5, -0.5 // 7 ]); // Indices of the cube var indicies = new Int16Array([ 0, 1, 2, 1, 2, 3, // front 5, 4, 6, 5, 6, 7, // back 0, 1, 5, 0, 5, 4, // left 2, 3, 6, 6, 3, 7, // right 0, 4, 2, 4, 2, 6, // top 5, 3, 1, 5, 3, 7 // bottom ]); // create vertices object on the GPU vbo = gl.createBuffer(); gl.bindBuffer(gl.ARRAY_BUFFER, vbo); gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW); // Create indicies object on th GPU ibo = gl.createBuffer(); gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, ibo); gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indicies, gl.STATIC_DRAW); gl.clearColor(0.0, 0.0, 0.0, 1.0); gl.enable(gl.DEPTH_TEST); // Render scene every 33 milliseconds setInterval(render, 33); } var mvMatrix = mat4.create(); var pMatrix = mat4.create(); function render() { // Set our viewport and clear it before we render gl.viewport(0, 0, canvas.width, canvas.height); gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT); gl.useProgram(program); // Bind appropriate VBOs gl.bindBuffer(gl.ARRAY_BUFFER, vbo); gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, ibo); // Set the color for the fragment shader program.uColor = gl.getUniformLocation(program, "uColor"); gl.uniform4fv(program.uColor, [0.3, 0.3, 0.3, 1.0]); // // code.google.com/p/glmatrix/wiki/Usage program.uPMatrix = gl.getUniformLocation(program, "uPMatrix"); program.uMVMatrix = gl.getUniformLocation(program, "uMVMatrix"); mat4.perspective(45, gl.viewportWidth / gl.viewportHeight, 1.0, 10.0, pMatrix); mat4.identity(mvMatrix); mat4.translate(mvMatrix, [0.0, -0.25, -1.0]); gl.uniformMatrix4fv(program.uPMatrix, false, pMatrix); gl.uniformMatrix4fv(program.uMVMatrix, false, mvMatrix); // Set the position for the vertex shader program.aVertexPosition = gl.getAttribLocation(program, "aVertexPosition"); gl.enableVertexAttribArray(program.aVertexPosition); gl.vertexAttribPointer(program.aVertexPosition, 3, gl.FLOAT, false, 3*4, 0); // position // Render the Object gl.drawElements(gl.TRIANGLES, 36, gl.UNSIGNED_SHORT, 0); } Thanks in advance for any help