WebGL Beginner's Guide - Code / 1727_05 / ch5_LocalTransformation.html

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<html>

<head>
<title>WebGL Beginner's Guide - Chapter 5 - Global vs Local Transformations</title>
<meta http-equiv='content-type' content='text/html; charset=ISO-8859-1'>

<!-- CSS Styles //-->
<link href='css/styles.css'   type='text/css' rel='stylesheet'>
<link href='css/prettify_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' />
<!-- GUI Libraries //-->
<script type='text/javascript' src='js/gui/jquery-1.5.1.min.js'></script>
<script type='text/javascript' src='js/gui/jquery-ui-1.8.13.custom.min.js'></script> 
<script type='text/javascript' src='js/gui/colorpicker.js'></script>
<script type='text/javascript' src='js/gui/prettify.js'></script>
<script type='text/javascript' src='js/gui/codeview.js'></script>
<!-- MATH Libraries //-->
<script type='text/javascript' src='js/math/gl-matrix-min.js'></script>
<!-- WEBGL Libraries //-->
<script type='text/javascript' src='js/webgl/Globals.js'></script>
<script type='text/javascript' src='js/webgl/Utils.js'></script>
<script type='text/javascript' src='js/webgl/Program.js'></script>
<script type='text/javascript' src='js/webgl/Scene.js'></script>
<script type='text/javascript' src='js/webgl/Axis.js'></script>
<script type='text/javascript' src='js/webgl/Floor.js'></script>
<script type='text/javascript' src='js/webgl/Camera.js'></script>
<script type='text/javascript' src='js/webgl/CameraInteractor.js'></script>
<script type='text/javascript' src='js/webgl/SceneTransforms.js'></script>
<script type='text/javascript' src='js/webgl/WebGLApp.js'></script>



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

attribute vec3 aVertexPosition;
attribute vec3 aVertexNormal;
attribute vec4 aVertexColor;

uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;
uniform mat4 uNMatrix;
uniform vec3 uLightPosition;
uniform vec4 uMaterialDiffuse;
uniform bool uWireframe;
uniform bool uPerVertexColor;
uniform bool uUpdateLight;

varying vec3 vNormal;
varying vec3 vLightRay;
varying vec3 vEyeVec;
varying vec4 vFinalColor;

void main(void) {
	
  if (uWireframe) {
        if (uPerVertexColor){
            vFinalColor = aVertexColor;
        }
        else{
            vFinalColor = uMaterialDiffuse;
        }
    }


 //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 = vec4(uLightPosition,1.0);
 
 if(uUpdateLight){
     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 bool uWireframe;
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;
varying vec4 vFinalColor;

void main(void)
{
	if(uWireframe){
		gl_FragColor = vFinalColor;
	}
	else{
    	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 camera = null;
var interactor = null;
var transforms = null;

function configure(){
    gl.clearColor(0.3,0.3,0.3, 1.0);
    gl.clearDepth(100.0);
    gl.enable(gl.DEPTH_TEST);
    gl.depthFunc(gl.LEQUAL);
    
    //Creates and sets up the camera location
    camera = new Camera(CAMERA_ORBITING_TYPE);
    camera.goHome([0,2,50]);
    camera.setFocus([0.0,0.0,0.0]);
    camera.hookRenderer = draw;
    
    //Creates and sets up the mouse and keyboard interactor
    interactor = new CameraInteractor(camera, document.getElementById('canvas-element-id'));
    
    //Scene Transforms
    transforms = new SceneTransforms(camera);
   
    //init transforms
    transforms.init();
}


/**
* Loads the scene
*/
function load(){
  
    Floor.build(80,2);
    Axis.build(82);
    Scene.addObject(Floor);
    Scene.addObject(Axis);
    Scene.loadObject('models/geometry/sphere.json','sphere');
    Scene.loadObject('models/geometry/cone.json','cone');
}



/**
* invoked on every rendering cycle
*/
function draw() {
    gl.viewport(0, 0, c_width, c_height);
    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
    transforms.updatePerspective();
    
    try{
        gl.uniform1i(prg.uUpdateLight,updateLightPosition);
        
        for (var i = 0; i < Scene.objects.length; i++){
            
            var object = Scene.objects[i];
			
			transforms.calculateModelView();           
            transforms.push();
            if (object.alias == 'sphere'){
            	var sphereTransform  = transforms.mvMatrix;
            	mat4.translate(sphereTransform,[0,0,pos_sphere]);
            }
            else if (object.alias == 'cone'){
                var coneTransform = transforms.mvMatrix;
                mat4.translate(coneTransform, [pos_cone,0,0]);
            }
            transforms.setMatrixUniforms();
            transforms.pop();
            
            //Setting uniforms
            gl.uniform4fv(prg.uMaterialDiffuse, object.diffuse);
            gl.uniform4fv(prg.uMaterialSpecular, object.specular);
            gl.uniform4fv(prg.uMaterialAmbient, object.ambient);
            
            gl.uniform1i(prg.uWireframe,object.wireframe);
            gl.uniform1i(prg.uPerVertexColor, object.perVertexColor);
            
            //Setting attributes
            gl.enableVertexAttribArray(prg.aVertexPosition);
            gl.disableVertexAttribArray(prg.aVertexNormal);
            gl.disableVertexAttribArray(prg.aVertexColor);
            
            gl.bindBuffer(gl.ARRAY_BUFFER, object.vbo);
            gl.vertexAttribPointer(prg.aVertexPosition, 3, gl.FLOAT, false, 0, 0);
            gl.enableVertexAttribArray(prg.aVertexPosition);
            
            if(!object.wireframe){
                gl.bindBuffer(gl.ARRAY_BUFFER, object.nbo);
                gl.vertexAttribPointer(prg.aVertexNormal, 3, gl.FLOAT, false, 0, 0);
                gl.enableVertexAttribArray(prg.aVertexNormal);
            }
            
            if (object.perVertexColor){
                gl.bindBuffer(gl.ARRAY_BUFFER, object.cbo);
                gl.vertexAttribPointer(prg.aVertexColor,4,gl.FLOAT, false, 0,0);
                gl.enableVertexAttribArray(prg.aVertexColor);
            }
            
            gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, object.ibo);
            
            if (object.wireframe){
                gl.drawElements(gl.LINES, object.indices.length, gl.UNSIGNED_SHORT,0);
            }
            else{
                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);
        console.error(err.description);
    }
}



var dx_sphere = 0.1;
var dx_cone = 0.15;
var pos_sphere = 0;
var pos_cone = 0;

var frequency = 5; 
var elapsedTime = undefined;
var initialTime = undefined;

function animate(){
	pos_sphere += dx_sphere;
    if (pos_sphere >= 30 || pos_sphere <=-30){
    	dx_sphere = -dx_sphere;
    }
    
    pos_cone += dx_cone;
    if (pos_cone >= 35 || pos_cone <=-35){
    	dx_cone = -dx_cone;
    }
	draw();
}

function onFrame(){
    elapsedTime = (new Date).getTime() - initialTime;
    if (elapsedTime < frequency) return; //come back later!
    
    var steps = Math.floor(elapsedTime / frequency);
    while(steps > 0){
        animate();
        steps -= 1;
    }
    initialTime = (new Date).getTime();
}

function startAnimation(){
    initialTime = (new Date).getTime();
	setInterval(onFrame,frequency/1000);
}


/**
* Entry point. This function is invoked when the page is loaded
*/
var app = null;
function runWebGLApp() {
    app = new WebGLApp("canvas-element-id")
    app.configureGLHook = configure;
    app.loadSceneHook   = load;
    app.drawSceneHook   = draw;
    app.run();
    
    startAnimation();

}
</script>
</head>

<body onLoad='runWebGLApp()'>
<div id='top'>
<h1>WebGL Beginner's Guide - Chapter 5</h1>
<h2>Global vs Local Transformations</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> 
    <table cellspacing=4px style='vertical-align:top'>
        <tr>
            <td align='center'>
            <div id='opt-type' >
                    <input type='radio' id='opt-tracking' name='typecam' /><label for='opt-tracking'>Tracking</label>
                    <input type='radio' id='opt-orbiting' name='typecam' checked='checked'/><label for='opt-orbiting'>Orbiting</label>
            </div>
            </td>
            <td align='center'>
            <button id='btnGoHome'>Go Home</button>
            <input type="checkbox" id="chkUpdateLight" /><label for="chkUpdateLight">Fixed Light Source</label>
            </td>
        </tr>
    </table>
    </td>
</tr>
</table>
</div>
<script> 

$('#chkUpdateLight').button();
$('#opt-type').buttonset();
$('#btnGoHome').button();


$('#chkUpdateLight').click(toggleLight);

$('#opt-tracking').click(function(){
    camera.goHome();
    console.info('CameraType = Tracking');
    camera.setType(CAMERA_TRACKING_TYPE);
    
    app.refresh();
});

$('#opt-orbiting').click(function(){
    camera.goHome();
    console.info('CameraType = Orbiting');
    camera.setType(CAMERA_ORBITING_TYPE);
    app.refresh();
});


var updateLightPosition = false;

function toggleLight(){
    updateLightPosition = !updateLightPosition;
}

$('#btnGoHome').click(
    function(){
        camera.goHome();
        app.refresh();
});



</script>
<script>cview.run(cview.MODE_VIEW,false,470);</script>
</body>
</html>
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