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HTML

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About the <head>

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. If you need things in the <head> of the document, put that code here.

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CSS

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CSS Base

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JavaScript

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HTML 

              
                
<!DOCTYPE html>
<html>

<script type="text/javascript" src="https://www.cs.unm.edu/~angel/WebGL/7E/Common/webgl-utils.js"></script>
<script type="text/javascript" src="https://www.cs.unm.edu/~angel/WebGL/7E/Common/initShaders.js"></script>
<script type="text/javascript" src="https://www.cs.unm.edu/~angel/WebGL/7E/Common/MV.js"></script>

<script id="vertex-shader" type="x-shader/x-vertex">

attribute  vec4 vPosition;
attribute  vec3 vNormal;
attribute  vec4 vColor;
varying vec4 fColor;

uniform vec4 ambientProduct, diffuseProduct, specularProduct;
uniform mat4 modelViewMatrix;
uniform mat4 projectionMatrix;
uniform vec4 lightPosition;
uniform float shininess;

void main()
{
    vec3 pos = -(modelViewMatrix * vPosition).xyz;
    vec3 light = lightPosition.xyz;
    vec3 L = normalize( light - pos );

	
    vec3 E = normalize( -pos );
    vec3 H = normalize( L + E );
    
    vec4 NN = vec4(vNormal,0);

    // Transform vertex normal into eye coordinates
    vec3 N = normalize( (modelViewMatrix*NN).xyz);

    // Compute terms in the illumination equation
    //vec4 ambient = ambientProduct;
    vec4 ambient = 0.5*vColor;

    float Kd = max( dot(L, N), 0.0 );
    vec4  diffuse = Kd*diffuseProduct;

    float Ks = pow( max(dot(N, H), 0.0), shininess );
    vec4  specular = Ks * specularProduct;
    
    if( dot(L, N) < 0.0 ) {
	specular = vec4(0.0, 0.0, 0.0, 1.0);
    } 

    gl_Position = projectionMatrix * modelViewMatrix * vPosition;
    fColor = ambient + diffuse +specular;
    
    fColor.a = 1.0;
} 
</script>

<script id="fragment-shader" type="x-shader/x-fragment">
precision mediump float;

uniform int i;

varying vec4 fColor;

void main()
{
    vec4 c[7];
    c[0] = fColor;
    c[1] = vec4(1.0, 0.0, 0.0, 1.0);
    c[2] = vec4(0.0, 1.0, 0.0, 1.0);
    c[3] = vec4(0.0, 0.0, 1.0, 1.0);
    c[4] = vec4(1.0, 1.0, 0.0, 1.0);
    c[5] = vec4(0.0, 1.0, 1.0, 1.0);
    c[6] = vec4(1.0, 0.0, 1.0, 1.0);
    

    if(i==0) gl_FragColor = c[0];
    else if(i==1) gl_FragColor = c[1];
    else if(i==2) gl_FragColor = c[2];
    else if(i==3) gl_FragColor = c[3];
    else if(i==4) gl_FragColor = c[4];
    else if(i==5) gl_FragColor = c[5];
    else if(i==6) gl_FragColor = c[6];
}
</script>


<body>
<div>
<canvas id="gl-canvas" width="512" height="512">
Oops ... your browser doesn't support the HTML5 canvas element
</canvas>
</div>
<div>
<button id = "ButtonX">Rotate X</button>
<button id = "ButtonY">Rotate Y</button>
<button id = "ButtonZ">Rotate Z</button>
<button id = "ButtonT">Toggle Rotation</button>
</div>
<div id = "test">
face
</div>
</body>
</html>
!

CSS
!

JS 

              
                var elt;

var canvas;
var gl;

var program;

var NumVertices  = 36;

var pointsArray = [];
var normalsArray = [];
var colorsArray = [];

var framebuffer;

var flag = true;

var color = new Uint8Array(4);

var vertices = [
        vec4( -0.5, -0.5,  0.5, 1.0 ),
        vec4( -0.5,  0.5,  0.5, 1.0 ),
        vec4( 0.5,  0.5,  0.5, 1.0 ),
        vec4( 0.5, -0.5,  0.5, 1.0 ),
        vec4( -0.5, -0.5, -0.5, 1.0 ),
        vec4( -0.5,  0.5, -0.5, 1.0 ),
        vec4( 0.5,  0.5, -0.5, 1.0 ),
        vec4( 0.5, -0.5, -0.5, 1.0 ),
    ];
    
var vertexColors = [
        vec4( 0.0, 0.0, 0.0, 1.0 ),  // black
        vec4( 1.0, 0.0, 0.0, 1.0 ),  // red
        vec4( 1.0, 1.0, 0.0, 1.0 ),  // yellow
        vec4( 0.0, 1.0, 0.0, 1.0 ),  // green
        vec4( 0.0, 0.0, 1.0, 1.0 ),  // blue
        vec4( 1.0, 0.0, 1.0, 1.0 ),  // magenta
        vec4( 0.0, 1.0, 1.0, 1.0 ),  // cyan
        vec4( 1.0, 1.0, 1.0, 1.0 ),   // white
    ];


var lightPosition = vec4(1.0, 1.0, 1.0, 0.0 );
var lightAmbient = vec4(0.2, 0.2, 0.2, 1.0 );
var lightDiffuse = vec4( 1.0, 1.0, 1.0, 1.0 );
var lightSpecular = vec4( 1.0, 1.0, 1.0, 1.0 );

//var materialAmbient = vec4( 1.0, 0.0, 1.0, 1.0 );
var materialAmbient = vec4( 1.0, 1.0, 1.0, 1.0 );
//var materialDiffuse = vec4( 1.0, 0.8, 0.0, 1.0);
var materialDiffuse = vec4( 0.5, 0.5, 0.5, 1.0);
var materialSpecular = vec4( 1.0, 0.8, 0.0, 1.0 );
var materialShininess = 10.0;

var ctm;
var ambientColor, diffuseColor, specularColor;
var modelView, projection;
var viewerPos;
var program;

var xAxis = 0;
var yAxis = 1;
var zAxis = 2;
var axis = xAxis;

var theta = [45.0, 45.0, 45.0];

var thetaLoc;

var Index = 0;


function quad(a, b, c, d) {

     var t1 = subtract(vertices[b], vertices[a]);
     var t2 = subtract(vertices[c], vertices[b]);
     var normal = cross(t1, t2);
     var normal = vec3(normal);
     normal = normalize(normal);

     pointsArray.push(vertices[a]); 
     normalsArray.push(normal); 
     colorsArray.push(vertexColors[a]);
     pointsArray.push(vertices[b]); 
     normalsArray.push(normal); 
     colorsArray.push(vertexColors[a]);
     pointsArray.push(vertices[c]); 
     normalsArray.push(normal);  
     colorsArray.push(vertexColors[a]); 
     pointsArray.push(vertices[a]);  
     normalsArray.push(normal); 
     colorsArray.push(vertexColors[a]);
     pointsArray.push(vertices[c]); 
     normalsArray.push(normal); 
     colorsArray.push(vertexColors[a]);
     pointsArray.push(vertices[d]); 
     normalsArray.push(normal);  
     colorsArray.push(vertexColors[a]);  
}


function colorCube()
{
    quad( 1, 0, 3, 2 );
    quad( 2, 3, 7, 6 );
    quad( 3, 0, 4, 7 );
    quad( 6, 5, 1, 2 );
    quad( 4, 5, 6, 7 );
    quad( 5, 4, 0, 1 );
}


window.onload = function init() {
    canvas = document.getElementById( "gl-canvas" );
    
    var ctx = canvas.getContext("experimental-webgl", {preserveDrawingBuffer: true});
    
    gl = WebGLUtils.setupWebGL( canvas );
    if ( !gl ) { alert( "WebGL isn't available" ); }
    
  
    // Element to show color name
    elt = document.getElementById("test");


    gl.viewport( 0, 0, canvas.width, canvas.height );
    gl.clearColor( 0.5, 0.5, 0.5, 1.0 );
    
    gl.enable(gl.CULL_FACE);
    
    var texture = gl.createTexture();
    gl.bindTexture( gl.TEXTURE_2D, texture );
    gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, true);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 512, 512, 0, 
       gl.RGBA, gl.UNSIGNED_BYTE, null);
    gl.generateMipmap(gl.TEXTURE_2D);

// Allocate a frame buffer object

   framebuffer = gl.createFramebuffer();
   gl.bindFramebuffer( gl.FRAMEBUFFER, framebuffer);


// Attach color buffer

   gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);

// check for completeness

   //var status = gl.checkFramebufferStatus(gl.FRAMEBUFFER);
   //if(status != gl.FRAMEBUFFER_COMPLETE) alert('Frame Buffer Not Complete');

gl.bindFramebuffer(gl.FRAMEBUFFER, null);

    //
    //  Load shaders and initialize attribute buffers
    //
    program = initShaders( gl, "vertex-shader", "fragment-shader" );
    gl.useProgram( program );
    
    colorCube();
    
    var cBuffer = gl.createBuffer();
    gl.bindBuffer( gl.ARRAY_BUFFER, cBuffer );
    gl.bufferData( gl.ARRAY_BUFFER, flatten(colorsArray), gl.STATIC_DRAW );
    
    var vColor = gl.getAttribLocation( program, "vColor" );
    gl.vertexAttribPointer( vColor, 4, gl.FLOAT, false, 0, 0 );
    gl.enableVertexAttribArray( vColor );


    var nBuffer = gl.createBuffer();
    gl.bindBuffer( gl.ARRAY_BUFFER, nBuffer );
    gl.bufferData( gl.ARRAY_BUFFER, flatten(normalsArray), gl.STATIC_DRAW );
    
    var vNormal = gl.getAttribLocation( program, "vNormal" );
    gl.vertexAttribPointer( vNormal, 3, gl.FLOAT, false, 0, 0 );
    gl.enableVertexAttribArray( vNormal );

    var vBuffer = gl.createBuffer();
    gl.bindBuffer( gl.ARRAY_BUFFER, vBuffer );
    gl.bufferData( gl.ARRAY_BUFFER, flatten(pointsArray), gl.STATIC_DRAW );
    
    var vPosition = gl.getAttribLocation(program, "vPosition");
    gl.vertexAttribPointer(vPosition, 4, gl.FLOAT, false, 0, 0);
    gl.enableVertexAttribArray(vPosition);
    
    viewerPos = vec3(0.0, 0.0, -20.0 );

    projection = ortho(-1, 1, -1, 1, -100, 100);
    
    ambientProduct = mult(lightAmbient, materialAmbient);
    diffuseProduct = mult(lightDiffuse, materialDiffuse);
    specularProduct = mult(lightSpecular, materialSpecular); 
    
    document.getElementById("ButtonX").onclick = function(){axis = xAxis;};
    document.getElementById("ButtonY").onclick = function(){axis = yAxis;};
    document.getElementById("ButtonZ").onclick = function(){axis = zAxis;};
    document.getElementById("ButtonT").onclick = function(){flag = !flag};
    
    gl.uniform4fv(gl.getUniformLocation(program, "ambientProduct"),
       flatten(ambientProduct));
    gl.uniform4fv(gl.getUniformLocation(program, "diffuseProduct"),
       flatten(diffuseProduct) );
    gl.uniform4fv(gl.getUniformLocation(program, "specularProduct"), 
       flatten(specularProduct) );	
    gl.uniform4fv(gl.getUniformLocation(program, "lightPosition"), 
       flatten(lightPosition) );
       
    gl.uniform1f(gl.getUniformLocation(program, 
       "shininess"),materialShininess);
    
    gl.uniformMatrix4fv( gl.getUniformLocation(program, "projectionMatrix"),
       false, flatten(projection));


    canvas.addEventListener("mousedown", function(event){
        
        gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
        gl.clear( gl.COLOR_BUFFER_BIT);
        gl.uniform3fv(thetaLoc, theta);
        for(var i=0; i<6; i++) {
            gl.uniform1i(gl.getUniformLocation(program, "i"), i+1);
            gl.drawArrays( gl.TRIANGLES, 6*i, 6 );
        }
        var x = event.clientX;
        var y = canvas.height -event.clientY;
          
        gl.readPixels(x, y, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, color);

      if (color[0] == 255) {
        if (color[1] == 255) {
          elt.innerHTML = "<div> cyan </div>";
        } else if (color[2] == 255) {
          elt.innerHTML = "<div> magenta </div>";
        } else {
          elt.innerHTML = "<div> red </div>";
        }
      } else if (color[1] == 255) {
        if (color[2] == 255) {
          elt.innerHTML = "<div> blue </div>";
        } else {
          elt.innerHTML = "<div> yellow </div>";
        }
      } else if (color[2] == 255) {
        elt.innerHTML = "<div> green </div>";
      } else {
        elt.innerHTML = "<div> background </div>";
      }

        // Real render
        gl.bindFramebuffer(gl.FRAMEBUFFER, null);

        gl.uniform1i(gl.getUniformLocation(program, "i"), 0);
        gl.clear( gl.COLOR_BUFFER_BIT );
        gl.uniform3fv(thetaLoc, theta);
        gl.drawArrays(gl.TRIANGLES, 0, 36);

    }); 
          
    render();
}

var render = function(){
    gl.clear( gl.COLOR_BUFFER_BIT );
    if(flag) theta[axis] += 2.0;
    modelView = mat4();
    modelView = mult(modelView, rotate(theta[xAxis], [1, 0, 0] ));
    modelView = mult(modelView, rotate(theta[yAxis], [0, 1, 0] ));
    modelView = mult(modelView, rotate(theta[zAxis], [0, 0, 1] ));
    
    gl.uniformMatrix4fv( gl.getUniformLocation(program,
            "modelViewMatrix"), false, flatten(modelView) );

    gl.uniform1i(gl.getUniformLocation(program, "i"),0);
    gl.drawArrays( gl.TRIANGLES, 0, 36 );

    requestAnimFrame(render);
}
!
999px

Console