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<!--
O3D Tutorial
In this tutorial, we load and display a scene in O3D and then
apply a procedural texture to it.
-->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>
Applying a Procedural Texture to a scene
</title>
<!-- Include sample javascript library functions-->
<script type="text/javascript" src="o3djs/base.js"></script>
<!-- Our javascript code -->
<script type="text/javascript" id="o3dscript">
o3djs.require('o3djs.util');
o3djs.require('o3djs.rendergraph');
o3djs.require('o3djs.pack');
o3djs.require('o3djs.camera');
o3djs.require('o3djs.scene');
// Events
// init() once the page has finished loading.
window.onload = init;
// global variables
var g_o3d;
var g_client;
var g_viewInfo;
var g_pack;
var g_finished = false; // for selenium testing
/**
* Loads a scene into the transform graph.
* @param {!o3d.Pack} pack Pack to load scene into.
* @param {string} fileName filename of the scene.
* @param {!o3d.Transform} parent parent node in the transform graph to
* which to load the scene into.
*/
function loadScene(pack, fileName, parent) {
// Get our full path to the scene
var scenePath = o3djs.util.getCurrentURI() + fileName;
// Load the file given the full path, and call the callback function
// when its done loading.
o3djs.scene.loadScene(g_client, pack, parent, scenePath, callback);
/**
* Our callback is called once the scene has been loaded into memory
* from the web or locally.
* @param {!o3d.Pack} pack The pack that was passed in above.
* @param {!o3d.Transform} parent The parent that was passed in above.
* @param {*} exception null if loading succeeded.
*/
function callback(pack, parent, exception) {
if (exception) {
alert('Could not load: ' + fileName + '\n' + exception);
return;
}
// Get a CameraInfo (an object with a view and projection matrix)
// using our javascript library function
var cameraInfo = o3djs.camera.getViewAndProjectionFromCameras(
parent,
g_client.width,
g_client.height);
// Copy the view and projection to the draw context.
g_viewInfo.drawContext.view = cameraInfo.view;
g_viewInfo.drawContext.projection = cameraInfo.projection;
// Add our checker pattern
createCheckerBoard(pack, 'Material__26');
// Generate draw elements and setup material draw lists.
o3djs.pack.preparePack(pack, g_viewInfo);
g_finished = true; // for selenium testing.
}
}
/**
* In order to apply the texture you must know the material name which you wish
* to change. The bulk of the calculation takes place in the shader itself.
* Alternatively, you could change the first or all the materials if you don't
* know the material name.
* @param {!o3d.Pack} pack The pack the scene was loaded into.
* @param {string} materialName Name of material you wish to turn into checkers.
*/
function createCheckerBoard(pack, materialName) {
var effectString = document.getElementById('checkerShader').value;
var effect = g_pack.createObject('Effect');
effect.loadFromFXString(effectString);
var materials = pack.getObjects(materialName, 'o3d.Material');
for (var m = 0; m < materials.length; m++) {
var material = materials[m];
// Set the material to use the checker effect.
material.effect = effect;
// Create any parameters the effect needs on the material.
effect.createUniformParameters(material);
}
}
/**
* Creates the client area.
*/
function init() {
o3djs.util.makeClients(initStep2);
}
/**
* Initializes O3D and loads the scene into the transform graph.
* @param {Array} clientElements Array of o3d object elements.
*/
function initStep2(clientElements) {
// Initializes global variables and libraries.
var o3dElement = clientElements[0];
g_o3d = o3dElement.o3d;
g_client = o3dElement.client;
// Creates a pack to manage our resources/assets
g_pack = g_client.createPack();
// Create the render graph for a view.
g_viewInfo = o3djs.rendergraph.createBasicView(
g_pack,
g_client.root,
g_client.renderGraphRoot);
// Creates a transform to put our data on.
var myDataRoot = g_pack.createObject('Transform');
// Connects our root to the client's root.
myDataRoot.parent = g_client.root;
// Load the scene into the transform graph as a child myDataRoot
loadScene(g_pack, 'assets/teapot.o3dtgz', myDataRoot);
}
</script>
</head>
<body>
<h1>Applying a Procedural Texture to a scene</h1>
This tutorial shows how to apply a procedural texture to a scene.
<br/>
<!-- Start of O3D plugin -->
<div id="o3d" style="width: 600px; height: 600px;"></div>
<!-- End of O3D plugin -->
<!-- Don't render the textarea -->
<div style="display:none">
<textarea id="checkerShader" name="checkerShader" cols="80" rows="20">
// The 4x4 world view projection matrix.
float4x4 worldViewProjection : WORLDVIEWPROJECTION;
// input parameters for our vertex shader
struct a2v {
float4 position : POSITION;
float3 normal : NORMAL;
float2 texcoord : TEXCOORD0;
};
// input parameters for our pixel shader
struct v2f {
float4 position : POSITION;
float4 col : COLOR;
float2 texcoord : TEXCOORD0;
};
// function for getting the checker pattern
float4 checker(float2 uv) {
float checkSize = 4;
float fmodResult = fmod(floor(checkSize * uv.x) + floor(checkSize * uv.y),
2.0);
if (fmodResult < 1) {
return float4(0, 1, 1, 1);
} else {
return float4(1, 0, 1, 1);
}
}
/**
* Our vertex shader. In the vertex shader, we calculate the lighting.
* Then we'll combine it with our checker pattern in the pixel shader.
*/
v2f vertexShaderFunction(a2v input) {
v2f output;
output.position = mul(input.position, worldViewProjection);
/**
* lightVector - light vector
* normal - normal vector
* We put the light such that it illuminates our model.
*/
float4 diffuseColor = float4(1, 1, 1, 1);
float3 lightPos = float3(1000, -1000, 1000);
float3 lightVector = normalize(lightPos - input.position.xyz);
float3 normal = normalize(input.normal);
float4 diffuse = dot(normal, lightVector) * diffuseColor;
output.col = diffuse;
output.texcoord = input.texcoord;
return output;
}
/**
* Our pixel shader. We take the lighting color we got from the vertex sahder
* and combine it with our checker pattern.
*/
float4 pixelShaderFunction(v2f input): COLOR {
float4 check = checker(input.texcoord);
float4 color = input.col * check;
return color;
}
// Here we tell our effect file *which* functions are
// our vertex and pixel shaders.
// #o3d VertexShaderEntryPoint vertexShaderFunction
// #o3d PixelShaderEntryPoint pixelShaderFunction
// #o3d MatrixLoadOrder RowMajor
</textarea>
</div>
</body>
</html>
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