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WebGL Beginner's Guide - Code / 1727_06 / ch6_Culling.html

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<!DOCTYPE html>
<html>

<head>
<title>WebGL Beginner's Guide - Chapter 6 - Transparent Objects</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">
//geometry
attribute vec3 aVertexPosition;
attribute vec3 aVertexNormal;
attribute vec4 aVertexColor;
uniform bool uUseVertexColor;
uniform vec4 uMaterialDiffuse;
uniform vec4 uMaterialAmbient;
uniform float uAlpha;

//matrices
uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;
uniform mat4 uNMatrix;

//lights
uniform vec3 uLightPosition;
uniform vec4 uLightAmbient;
uniform vec4 uLightDiffuse;

//varyings
varying vec4 vColor;


void main(void) {

 //Transformed vertex position
 vec4 vertex = uMVMatrix * vec4(aVertexPosition, 1.0);
 
 //we are not using lambert weighing in this exercise :-)
 float lambertTerm = 1.0;

 //reading vertex color
 vec4 Ia = uLightAmbient * uMaterialAmbient;
 vec4 Id = vec4(0.0);
 
 if (uUseVertexColor){
	Id = uLightDiffuse * aVertexColor * lambertTerm;
 }
 else {
	Id = uLightDiffuse * uMaterialDiffuse * lambertTerm;
 }
 
 vColor = Ia + Id;
 vColor.a = uAlpha;
 
 //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

//geometry
uniform vec4 uMaterialDiffuse;
uniform bool uWireframe;

//varying
varying vec4 vColor;

void main(void)
{
	if(uWireframe){
		gl_FragColor = uMaterialDiffuse;
	}
	else{
    	gl_FragColor = vColor;
    }

}
</script>

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

var camera           = null,
 interactor          = null,
 transforms          = null,
 useVertexColors     = true,
 blending            = true,
 blendingEquation    = undefined,
 blendingSource      = undefined,
 blendingTarget      = undefined,
 blendingColor       = [0.0, 1.0, 0.0],
 blendingAlpha       = 1.0,
 showFrontFace       = true,
 showBackFace        = true;

function configure(){


    gl.clearColor(0.3,0.3,0.3, 1.0);
    gl.clearDepth(1.0);
    
    //Enables depth testing
    gl.enable(gl.DEPTH_TEST);
    gl.depthFunc(gl.LESS);
	
    //Enables blending
	gl.enable(gl.BLEND);

	//Blending function for transparencies
    gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA);   
    gl.blendColor(blendingColor[0], blendingColor[1], blendingColor[2], blendingAlpha);    
    //Enable culling
    gl.enable(gl.CULL_FACE);

     blendingEquation    = gl.FUNC_ADD;
     blendingSource      = gl.SRC_ALPHA;
     blendingTarget      = gl.ONE_MINUS_SRC_ALPHA;    
    
    //Creates and sets up the camera location
    camera = new Camera(CAMERA_ORBITING_TYPE);
    camera.goHome([0,0,4]);
    camera.setFocus([0.0,0.0,0.0]);
	camera.setAzimuth(50);
	camera.setElevation(-30);
    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();
	
	//Program
	attributeList = ["aVertexPosition",
					"aVertexNormal",
					"aVertexColor"];

	uniformList = [	"uPMatrix", 
					"uMVMatrix", 
					"uNMatrix",
					"uMaterialDiffuse",
					"uMaterialAmbient",
					"uLightAmbient",
					"uLightDiffuse",
					"uLightPosition",
					"uWireframe",
					"uAlpha",
					"uUseVertexColor",
					"uUseLambert"
					];
	
	
	Program.load(attributeList, uniformList);
	
	gl.uniform3fv(Program.uLightPosition,   [0,5,20]);
	gl.uniform4fv(Program.uLightAmbient,    [1.0,1.0,1.0,1.0]);
	gl.uniform4fv(Program.uLightDiffuse,    [1.0,1.0,1.0,1.0]);
	gl.uniform1f(Program.uAlpha, 0.5);
	gl.uniform1i(Program.uUseVertexColor, useVertexColors);
	gl.uniform1i(Program.uUseLambert, false);

}



/**
* Loads the scene
*/
function load(){
	Scene.loadObject('models/geometry/complexCube.json','cube');
}




/**
* 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{
        for (var i = 0; i < Scene.objects.length; i++){
            
            var object = Scene.objects[i];
			
			
			transforms.calculateModelView();           
            transforms.push();
            transforms.setMatrixUniforms();
            transforms.pop();
   
            //Setting uniforms
            gl.uniform4fv(Program.uMaterialDiffuse, object.diffuse);
            gl.uniform4fv(Program.uMaterialAmbient, object.ambient);
            gl.uniform1i(Program.uWireframe,object.wireframe);
			
            
            //Setting attributes
            gl.enableVertexAttribArray(Program.aVertexPosition);
            gl.disableVertexAttribArray(Program.aVertexNormal);
            gl.disableVertexAttribArray(Program.aVertexColor);
            
            gl.bindBuffer(gl.ARRAY_BUFFER, object.vbo);
            gl.vertexAttribPointer(Program.aVertexPosition, 3, gl.FLOAT, false, 0, 0);
            gl.enableVertexAttribArray(Program.aVertexPosition);
			
			gl.uniform1i(Program.uUseVertexColor, useVertexColors);
			
			if (object.scalars != null && useVertexColors){
			    gl.enableVertexAttribArray(Program.aVertexColor);
				gl.bindBuffer(gl.ARRAY_BUFFER, object.cbo);
				gl.vertexAttribPointer(Program.aVertexColor, 4, gl.FLOAT, false, 0, 0);
				
			}
			
            
			if(!object.wireframe){
				gl.bindBuffer(gl.ARRAY_BUFFER, object.nbo);
				gl.vertexAttribPointer(Program.aVertexNormal, 3, gl.FLOAT, false, 0, 0);
				gl.enableVertexAttribArray(Program.aVertexNormal);
            }
			gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, object.ibo);
			
			if (object.wireframe){
                gl.drawElements(gl.LINES, object.indices.length, gl.UNSIGNED_SHORT,0);
            }
            else{
                if(showBackFace){
                    gl.cullFace(gl.FRONT);  //renders the back face
                    gl.drawElements(gl.TRIANGLES, object.indices.length, gl.UNSIGNED_SHORT,0);
                }
                if (showFrontFace){
                    gl.cullFace(gl.BACK);  //renders the front face
                    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);
    }
}


/**
* 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();
}
</script>
</head>

<body onLoad='runWebGLApp()'>
<div id='top'>
<h1>WebGL Beginner's Guide - Chapter 6</h1>
<h2>Creating Transparent Objects with Alpha Blending and Face Culling</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;margin-left:0px'>
<tr>
	<td>
	<table style='margin-left:0px'>
    <tr>
        <td>
        <input type="checkbox" id="blending-btn" checked='checked'/><label for="blending-btn">Alpha Blending</label>
        <input type="checkbox" id="show-front-btn" checked='checked'/><label for="show-front-btn">Render Front Face</label>
        <input type="checkbox" id="show-back-btn" checked='checked'/><label for="show-back-btn">Render Back Face</label>
        </td>
    </tr>
    <tr>    
        <td>
            <table width='100%'>
            <tr>
                <td>Alpha Value:</td>
                <td id='slider-alpha-value' width='15%'><b>0.5</b></td>
                <td width='80%'><div id='slider-alpha'/></td>
            </tr>
            </table>
        </td>  
    </tr>
    <tr>
        <td colspan='2'>
            <table>
            <tr>
                <td>Blend Function</td><td>Source</td><td>Destination</td>
            </tr>
            <tr>
            <td>
                <select name='Blend Equation' id='selBlendEquation'>
                    <option value='FUNC_ADD' selected='selected'>gl.FUNC_ADD</option>
                    <option value='FUNC_SUBTRACT'>gl.FUNC_SUBTRACT</option>
                    <option value='FUNC_REVERSE_SUBTRACT'>gl.FUNC_REVERSE_SUBTRACT</option>
                </select>
            </td>
            <td>
                <select name='Source' id='selSource'>
                    <option value='ZERO'>gl.ZERO</option>
                    <option value='ONE'>gl.ONE</option>
                    <option value='SRC_COLOR'>gl.SRC_COLOR</option>
                    <option value='DST_COLOR'>gl.DST_COLOR</option>
                    <option value='SRC_ALPHA' selected='selected'>gl.SRC_ALPHA</option>
                    <option value='DST_ALPHA'>gl.DST_ALPHA</option>
                    <option value='CONSTANT_COLOR'>gl.CONSTANT_COLOR</option>
                    <option value='CONSTANT_ALPHA'>gl.CONSTANT_ALPHA</option>
                    <option value='ONE_MINUS_SRC_ALPHA'>gl.ONE_MINUS_SRC_ALPHA</option>
                    <option value='ONE_MINUS_DST_ALPHA'>gl.ONE_MINUS_DST_ALPHA</option>
                    <option value='ONE_MINUS_SRC_COLOR'>gl.ONE_MINUS_SRC_COLOR</option>
                    <option value='ONE_MINUS_DST_COLOR'>gl.ONE_MINUS_DST_COLOR</option>
                    <option value='ONE_MINUS_CONSTANT_COLOR'>gl.ONE_MINUS_CONSTANT_COLOR</option>
                    <option value='ONE_MINUS_CONSTANT_ALPHA'>gl.ONE_MINUS_CONSTANT_ALPHA</option>
                    <option value='SRC_ALPHA_SATURATE'>gl.SRC_ALPHA_SATURATE</option>
                </select>    
            </td>
            <td>
                <select name='Target' id='selTarget'>
                    <option value='ZERO'>gl.ZERO</option>
                    <option value='ONE'>gl.ONE</option>
                    <option value='SRC_COLOR'>gl.SRC_COLOR</option>
                    <option value='DST_COLOR'>gl.DST_COLOR</option>
                    <option value='SRC_ALPHA'>gl.SRC_ALPHA</option>
                    <option value='DST_ALPHA'>gl.DST_ALPHA</option>
                    <option value='CONSTANT_COLOR'>gl.CONSTANT_COLOR</option>
                    <option value='CONSTANT_ALPHA'>gl.CONSTANT_ALPHA</option>
                    <option selected='selected' value='ONE_MINUS_SRC_ALPHA' >gl.ONE_MINUS_SRC_ALPHA</option>
                    <option value='ONE_MINUS_DST_ALPHA'>gl.ONE_MINUS_DST_ALPHA</option>
                    <option value='ONE_MINUS_SRC_COLOR'>gl.ONE_MINUS_SRC_COLOR</option>
                    <option value='ONE_MINUS_DST_COLOR'>gl.ONE_MINUS_DST_COLOR</option>
                    <option value='ONE_MINUS_CONSTANT_COLOR'>gl.ONE_MINUS_CONSTANT_COLOR</option>
                    <option value='ONE_MINUS_CONSTANT_ALPHA'>gl.ONE_MINUS_CONSTANT_ALPHA</option>
                </select>    
            </td>
           
            </tr>
            </table>
        </td>
    </tr>
    <tr><td>
        <table style='margin-left:0px'>
        <tr><td>Constant Blending Color (when applicable):</td>
            <td>
                <div id='blendingColorSelector' class='colorSelector'>
                <div style='background-color:rgb(128,205,26)'></div>
                </div>
            </td>
        </tr>
        </table>
        </td></tr><tr>
        <td>
        <table style='margin-left:0px'>
            <tr><td>Constant Alpha (when applicable):</td>
            <td id='slider-c-alpha-value' width='15%'><b>1.0</b></td>
            <td width='80%'><div id='slider-c-alpha'/></td>
            </td></tr>
        </table>
     </tr>
    </table>
</td></tr>	
</table>    
</div>
<script> 


$('#slider-alpha').slider({value:0.5, min:0.0, max:1.0, step:0.01, slide:updateAlpha, change:updateAlpha});

function updateAlpha(){
    var v = $('#slider-alpha').slider("value");
    gl.uniform1f(Program.uAlpha, v);
    $('#slider-alpha-value').html('<b>'+v+'</b>');
	app.refresh();
};

$('#slider-c-alpha').slider({value:1.0, min:0.0, max:1.00, step:0.05, slide:updateConstantAlpha, change:updateConstantAlpha});

function updateConstantAlpha(){
    var v = $('#slider-c-alpha').slider("value");
    $('#slider-c-alpha-value').html('<b>'+v+'</b>');
    blendingAlpha = v;
	updateBlending();
};


$('#blending-btn, #show-front-btn, #show-back-btn').button();
//$('#show-front-btn').button();


function updateBlending(){
    if (blending){
        gl.enable(gl.BLEND);
    }
    else{
        gl.disable(gl.BLEND);
    }
    gl.blendEquation(blendingEquation);
    gl.blendFunc(blendingSource, blendingTarget);
    gl.blendColor(blendingColor[0], blendingColor[1], blendingColor[2],blendingAlpha);
    app.refresh();
};




$('#blending-btn').click(function(){
  blending = $('#blending-btn').is(':checked');
  
  $('#selBlendEquation, #selSource, #selTarget').attr('disabled',blending?'':'disabled');
  updateBlending();
});

$('#show-front-btn').click(function(){
    showFrontFace = $('#show-front-btn').is(':checked');
});

$('#show-back-btn').click(function(){
    showBackFace = $('#show-back-btn').is(':checked');
});


$("#selBlendEquation").change(function (event) {
    blendingEquation = gl[event.target.value];
    updateBlending();
    
 });
 
$("#selSource").change(function (event) {
    blendingSource = gl[event.target.value];
    updateBlending();
 });

 $("#selTarget").change(function (event) {
    blendingTarget = gl[event.target.value];
    updateBlending();
 });

 
 $('#blendingColorSelector').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) {
        $('#blendingColorSelector div').css('backgroundColor', '#' + hex);
        blendingColor = [rgb.r/256,rgb.g/256,rgb.b/256];
        updateBlending();
    },
    
    onBeforeShow: function (colpkr) {
   $(this).ColorPickerSetColor('rgb(0.0,1.0,0.0)');
  }
 })

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