Source

WebGL Beginner's Guide - Code / 1727_03 / ch3_Positinal_Lighting.html

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<html>

<head>
<title>WebGL Beginner's Guide - Chapter 3 - Positional Lighting</title>
<meta http-equiv='content-type' content='text/html; charset=ISO-8859-1'>

<!-- CSS Styles //-->
<link href='css/style.css'   type='text/css' rel='stylesheet'>
<link href='css/desert.css'  type='text/css' rel='stylesheet'/>
<link href='css/colorpicker.css'  type='text/css' rel='stylesheet'/>
<link href='css/smoothness/jquery-ui-1.8.13.custom.css' type='text/css' rel='stylesheet' />

<!-- JavaScript Libraries //-->
<script type='text/javascript' src='js/gl-matrix-min.js'></script>
<script type='text/javascript' src='js/jquery-1.5.1.min.js'></script>
<script type='text/javascript' src='js/jquery-ui-1.8.13.custom.min.js'></script> 
<script type='text/javascript' src='js/prettify.js'></script>
<script type='text/javascript' src='js/utils.js'></script>
<script type='text/javascript' src='js/colorpicker.js'></script>
<script type='text/javascript' src='js/codeview.js'></script>

<script id="shader-vs" type="x-shader/x-vertex">
attribute vec3 aVertexPosition;
attribute vec3 aVertexNormal;

uniform mat4 uMVMatrix; 
uniform mat4 uPMatrix; 
uniform mat4 uNMatrix; 

uniform vec3 uLightPosition;

varying vec3 vNormal;
varying vec3 vLightRay;
varying vec3 vEyeVec;

void main(void) {

 //Transformed vertex position
 vec4 vertex = uMVMatrix * vec4(aVertexPosition, 1.0);
 
 //Transformed normal position
 vNormal = vec3(uNMatrix * vec4(aVertexNormal, 1.0));

 //Transformed light position
 vec4 light = uMVMatrix * vec4(uLightPosition,1.0);
	
 //Light position
 vLightRay = vertex.xyz-light.xyz;
 
 //Vector Eye
 vEyeVec = -vec3(vertex.xyz);
 
 //Final vertex position
 gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
 
}
</script>

<script id="shader-fs" type="x-shader/x-fragment">
#ifdef GL_ES
precision highp float;
#endif


uniform vec4 uLightAmbient;
uniform vec4 uLightDiffuse;
uniform vec4 uLightSpecular;

uniform vec4 uMaterialAmbient;
uniform vec4 uMaterialDiffuse;
uniform vec4 uMaterialSpecular;
uniform float uShininess;       

varying vec3 vNormal;
varying vec3 vLightRay;
varying vec3 vEyeVec;

void main(void)
{

    vec3 L = normalize(vLightRay);
    vec3 N = normalize(vNormal);

    //Lambert's cosine law
    float lambertTerm = dot(N,-L);
    
    //Ambient Term  
    vec4 Ia = uLightAmbient * uMaterialAmbient;

    //Diffuse Term
    vec4 Id = vec4(0.0,0.0,0.0,1.0);

    //Specular Term
    vec4 Is = vec4(0.0,0.0,0.0,1.0);

    if(lambertTerm > 0.0)
    {
        Id = uLightDiffuse * uMaterialDiffuse * lambertTerm; 
        vec3 E = normalize(vEyeVec);
        vec3 R = reflect(L, N);
        float specular = pow( max(dot(R, E), 0.0), uShininess);
        Is = uLightSpecular * uMaterialSpecular * specular;
    }

    //Final color
    vec4 finalColor = Ia + Id + Is;
    finalColor.a = 1.0;

    gl_FragColor = finalColor;

}
</script>



<script id='code-js' type="text/javascript">

var gl = null; // WebGL context
var prg = null; // The program (shaders)
var c_width = 0; // Variable to store the width of the canvas
var c_height = 0; // Variable to store the height of the canvas

var mvMatrix = mat4.create(); // The Model-View matrix
var pMatrix = mat4.create(); // The projection matrix
var nMatrix =  mat4.create();      // The normal matrix

var distance = -40;
var animateFlag = false;

var objects = [];   

/**
* The program contains a series of instructions that tell the Graphic Processing Unit (GPU)
* what to do with every vertex and fragment that we pass it. 
* The vertex shader and the fragment shader together are called the program.
*/
function initProgram() {
var fragmentShader      = utils.getShader(gl, "shader-fs");
var vertexShader        = utils.getShader(gl, "shader-vs");

prg = gl.createProgram();
gl.attachShader(prg, vertexShader);
gl.attachShader(prg, fragmentShader);
gl.linkProgram(prg);

if (!gl.getProgramParameter(prg, gl.LINK_STATUS)) {
alert("Could not initialise shaders");
}

gl.useProgram(prg);

prg.aVertexPosition     = gl.getAttribLocation(prg, "aVertexPosition");
prg.aVertexNormal       = gl.getAttribLocation(prg, "aVertexNormal");

prg.uPMatrix            = gl.getUniformLocation(prg, "uPMatrix");
prg.uMVMatrix           = gl.getUniformLocation(prg, "uMVMatrix");
prg.uNMatrix            = gl.getUniformLocation(prg, "uNMatrix");


prg.uMaterialAmbient    = gl.getUniformLocation(prg, "uMaterialAmbient");
prg.uMaterialDiffuse    = gl.getUniformLocation(prg, "uMaterialDiffuse");
prg.uMaterialSpecular   = gl.getUniformLocation(prg, "uMaterialSpecular");
prg.uShininess          = gl.getUniformLocation(prg, "uShininess");


prg.uLightPosition      = gl.getUniformLocation(prg, "uLightPosition");
prg.uLightAmbient       = gl.getUniformLocation(prg, "uLightAmbient");
prg.uLightDiffuse       = gl.getUniformLocation(prg, "uLightDiffuse");
prg.uLightSpecular      = gl.getUniformLocation(prg, "uLightSpecular");
}


function initLights(){
//Light uniforms
gl.uniform3fv(prg.uLightPosition,[4.5,3.0,15.0]);        
gl.uniform4f(prg.uLightAmbient ,1.0,1.0,1.0,1.0);
gl.uniform4f(prg.uLightDiffuse,1.0,1.0,1.0,1.0);
gl.uniform4f(prg.uLightSpecular,1.0,1.0,1.0,1.0);

//Object Uniforms
gl.uniform4f(prg.uMaterialAmbient, 0.1,0.1,0.1,1.0);
gl.uniform4f(prg.uMaterialDiffuse, 0.5,0.8,0.1,1.0);
gl.uniform4f(prg.uMaterialSpecular, 0.6,0.6,0.6,1.0);
gl.uniform1f(prg.uShininess, 200.0);

}


/**
* Creates an AJAX request to load the scene asynchronously
*/
function loadScene(){
loadObject('models/geometry/plane.json');
loadObject('models/geometry/cone.json','cone');
loadObject('models/geometry/sphere.json','sphere');
loadObject('models/geometry/smallsph.json','lightsource');
}

function getObject(alias){
for(var i=0; i<objects.length; i++){
if (alias == objects[i].alias) return objects[i];
}
return null;
}

/**
* Ajax and JSON in action
*/ 

function loadObject(filename,alias){
    var request = new XMLHttpRequest();
    console.info('Requesting ' + filename);
    request.open("GET",filename);
    
    request.onreadystatechange = function() {
    if (request.readyState == 4) {
        if(request.status == 404) {
            console.info(filename + ' does not exist');
        }
        else {
var o = JSON.parse(request.responseText);
o.alias = (alias==null)?'none':alias;
            handleLoadedObject(filename,o);
        }
    }
    }
    request.send();
}

/**
* Creates the buffers that contain the geometry of the object
*/
function handleLoadedObject(filename,object) {
    
    console.info(filename + ' has been retrieved from the server');
    
    var vertexBufferObject = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, vertexBufferObject);
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(object.vertices), gl.STATIC_DRAW);
    
        
    var normalBufferObject = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, normalBufferObject);
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(utils.calculateNormals(object.vertices, object.indices)), gl.STATIC_DRAW);
    
    var indexBufferObject = gl.createBuffer();
    gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBufferObject);
    gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(object.indices), gl.STATIC_DRAW);
        
    
    object.vbo = vertexBufferObject;
    object.ibo = indexBufferObject;
    object.nbo = normalBufferObject;

    gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, null);
    gl.bindBuffer(gl.ARRAY_BUFFER,null);
    
    objects.push(object);
} 

/**
* Main rendering function. Called every 500ms according to WebGLStart function (see below)
*/
function drawScene() {
    gl.clearColor(0.3,0.3,0.3, 1.0);
    gl.clearDepth(100.0);
    gl.enable(gl.DEPTH_TEST);
    gl.depthFunc(gl.LEQUAL);
    gl.viewport(0, 0, c_width, c_height);
    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
    mat4.perspective(30, c_width / c_height, 0.1, 1000.0, pMatrix);

    try{
        gl.enableVertexAttribArray(prg.aVertexPosition);
        gl.enableVertexAttribArray(prg.aVertexNormal);
        for (var i = 0; i < objects.length; i++){
            var object = objects[i];
            mat4.identity(mvMatrix);
            mat4.translate(mvMatrix, [0.0, 0.0, distance]); //Sets the camera to a reasonable distance to view the part
            mat4.rotate(mvMatrix, 30*Math.PI/180, [1,0,0]);
            mat4.rotate(mvMatrix, angle*Math.PI/180, [0,1,0]);
            if (object.alias == 'lightsource'){
                var lightPos = gl.getUniform(prg, prg.uLightPosition);
                mat4.translate(mvMatrix,lightPos);
                
            }
            
            gl.uniformMatrix4fv(prg.uMVMatrix, false, mvMatrix);
            gl.uniformMatrix4fv(prg.uPMatrix, false, pMatrix);
            mat4.set(mvMatrix, nMatrix);
            mat4.inverse(nMatrix);
            mat4.transpose(nMatrix);
            
            gl.uniformMatrix4fv(prg.uNMatrix, false, nMatrix);
            gl.uniform4fv(prg.uMaterialAmbient, object.ambient);
            gl.uniform4fv(prg.uMaterialDiffuse, object.diffuse);
            gl.uniform4fv(prg.uMaterialSpecular, object.specular);
            gl.bindBuffer(gl.ARRAY_BUFFER, object.vbo);
            gl.vertexAttribPointer(prg.aVertexPosition, 3, gl.FLOAT, false, 0, 0);
            gl.enableVertexAttribArray(prg.aVertexPosition);
            
            gl.bindBuffer(gl.ARRAY_BUFFER, object.nbo);
            gl.vertexAttribPointer(prg.aVertexNormal, 3, gl.FLOAT, false, 0, 0);
            gl.enableVertexAttribArray(prg.aVertexNormal);
            
            gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, object.ibo);
            gl.drawElements(gl.TRIANGLES, object.indices.length, gl.UNSIGNED_SHORT,0);
            gl.bindBuffer(gl.ARRAY_BUFFER, null);
            gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, null);
        }
    }
    catch(err){
        alert(err);
        message(err.description);
    }
}






var lastTime = 0;
var angle = 0;
/**
* Updates the angle of rotation by a little bit each time
*/
function animate() {
    var timeNow = new Date().getTime();
    if (lastTime != 0) {
        var elapsed = timeNow - lastTime;
        if (animateFlag) angle += (90 * elapsed) / 10000.0;
    }
    lastTime = timeNow;
}

/**
* Render Loop
*/
function renderLoop() {
    requestAnimFrame(renderLoop);
    drawScene();
animate();
}

/**
* Entry point. This function is invoked when the page is loaded
*/
function runWebGLApp() {
//Obtains a WebGL context
gl = utils.getGLContext("canvas-element-id");
//Initializes the program (shaders) 
    initProgram();
    //Initializes lights
    initLights();
    //Load Scene
loadScene();
    //Renders the scene!
    renderLoop();
}
</script>
</head>

<body onLoad='runWebGLApp()'>
<div id='top'>
<h1>WebGL Beginner's Guide - Chapter 3</h1>
<h2>Positional Lighting</h2>
<div id='logo-packt'><img src='packt.gif'/></div>
<p></p>
</div>

<div id='contents'>
<div id='canvasContainer'>
<canvas id='canvas-element-id' width='480' height='400'>
Your browser does not support the HTML5 canvas element.
</canvas>
</div>
</div>

<div id='bottom'>
<table style='padding=0px'>
<tr>
<td>X:</td><td id='slider-x-value' width='30px'>4.5</td><td width='150px'><div id='slider-x'/></td>
<td>Shininess:</td><td id='slider-shininess-value'>200</td><td width='150px'><div id='slider-shininess'/></td>
<td> Sphere Color:</td><td><div id='colorSelectorSphere' class='colorSelector'><div style='background-color:rgb(128,204,26)'></div></div></td>
</tr>
<tr>
<td>Y:</td><td id='slider-y-value'  width='30px'>3.0</td><td width='150px'><div id='slider-y'/></td>
<td>Distance:</td><td id='slider-distance-value'>40</td><td width='150px'><div id='slider-distance'/></td>
<td> Cone Color:</td><td><div id='colorSelectorCone' class='colorSelector'><div style='background-color:rgb(204,26,128)'></div></div></td>
</tr>
<tr>
<td>Z:</td> <td id='slider-z-value'  width='30px'>15.0</td><td width='150px'><div id='slider-z'/></td>
<td><label id='lblanimate' for='animate-btn'>Animate</label><input id='animate-btn' type='checkbox'/></td>
</tr>
</table>
</div>
<script>cview.run(cview.MODE_VIEW);</script>
<script> 
$('#slider-shininess').slider({value:200, min:1, max:300, step:1, slide:updateShininess});
$('#slider-distance').slider({value:40, min:10, max:100, step:1, slide:updateDistance});
$('#slider-x').slider({value:4.5, min:-50, max:50, step:0.1, slide:updateLightPosition, change:updateLightPosition});
$('#slider-y').slider({value:3.0, min:0, max:50, step:0.1, slide:updateLightPosition, change:updateLightPosition});
$('#slider-z').slider({value:15.0, min:-50, max:50, step:0.1, slide:updateLightPosition, change:updateLightPosition});


$('#animate-btn').button();
$('#animate-btn').click(
function(){
    if ($('#animate-btn:checked').val()==null){
        animateFlag = false;
    }
    else{
        animateFlag = true;
    }
});
function updateShininess(){
    var v = $('#slider-shininess').slider("value");
    gl.uniform1f(prg.uShininess, v);
    $('#slider-shininess-value').html(v);
}



function updateLightPosition(){
    var x = $('#slider-x').slider("value");
    var y = $('#slider-y').slider("value");
    var z = $('#slider-z').slider("value");
    gl.uniform3fv(prg.uLightPosition, [x,y,z]);
    $('#slider-x-value').html(x);
    $('#slider-y-value').html(y);
    $('#slider-z-value').html(z);
}


function updateDistance(){
    var d = $('#slider-distance').slider("value");
    $('#slider-distance-value').html(distance);
    distance = -d;
}



function updateObjectColor(alias, r,g,b){
    var object = getObject(alias);
    if (object != null){
        object.diffuse = [r,g,b,1.0];
    }

}

$('#colorSelectorSphere').ColorPicker({
onSubmit: function(hsb, hex, rgb, el) {
        $(el).val(hex);
        $(el).ColorPickerHide();

    },
color: '#00ff00',
onShow: function (colpkr) {
        $(colpkr).fadeIn(500);
        return false;
    },
onHide: function (colpkr) {
        $(colpkr).fadeOut(500);
        return false;
    },
onChange: function (hsb, hex, rgb) {
        $('#colorSelectorSphere div').css('backgroundColor', '#' + hex);
        updateObjectColor('sphere',rgb.r/256,rgb.g/256,rgb.b/256);
    },
    
onBeforeShow: function (colpkr) {
        $(colpkr).ColorPickerSetColor('rgb(0.5,0.8,0.1)');
    }
})

$('#colorSelectorCone').ColorPicker({
onSubmit: function(hsb, hex, rgb, el) {
        $(el).val(hex);
        $(el).ColorPickerHide();

    },
color: '#00ff00',
onShow: function (colpkr) {
        $(colpkr).fadeIn(500);
        return false;
    },
onHide: function (colpkr) {
        $(colpkr).fadeOut(500);
        return false;
    },
onChange: function (hsb, hex, rgb) {
        $('#colorSelectorCone div').css('backgroundColor', '#' + hex);
        updateObjectColor('cone',rgb.r/256,rgb.g/256,rgb.b/256);
    },
    
onBeforeShow: function (colpkr) {
        $(colpkr).ColorPickerSetColor('rgb(0.8,0.1,0.5)');
    }
}) 


</script>
</body>
</html>