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<!--
Copyright 2009, Google Inc.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
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* Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-->
<!--
O3D Vertex Shader Demo
This sample uses a custom vertex shader to quickly adjust the positions and
normals of many vertices in a plane to achieve a ripple effect without iterating
through the vertices in javascript.
-->
<!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>
Vertex Shader
</title>
<script type="text/javascript" src="o3djs/base.js"></script>
<script type="text/javascript" id="o3dscript">
o3djs.require('o3djs.util');
o3djs.require('o3djs.math');
o3djs.require('o3djs.rendergraph');
o3djs.require('o3djs.primitives');
o3djs.require('o3djs.effect');
// global variables
var g_o3dElement;
var g_client;
var g_o3d;
var g_math;
var g_pack;
var g_viewInfo;
var g_clockParam;
/**
* Creates the client area.
*/
function init() {
// These are here so that they are visible to both the browser (so
// selenium sees them) and the embedded V8 engine.
window.g_clock = 0;
window.g_timeMult = 1;
window.g_finished = false; // for selenium testing.
// Comment out the line below to run the sample in the browser
// JavaScript engine. This may be helpful for debugging.
o3djs.util.setMainEngine(o3djs.util.Engine.V8);
o3djs.util.makeClients(initStep2, 'LargeGeometry');
}
/**
* Initializes global variables, positions camera, creates the material, and
* draws the plane.
* @param {Array} clientElements Array of o3d object elements.
*/
function initStep2(clientElements) {
// Init global variables.
initGlobals(clientElements);
// Set up the view and projection transformations.
initContext();
// Add the shapes to the transform heirarchy.
createPlane();
// Setup render callback.
g_client.setRenderCallback(onRender);
window.g_finished = true; // for selenium testing.
}
/**
* Initializes global variables and libraries.
* @param {Array} clientElements An array of o3d object elements assumed
* to have one entry.
*/
function initGlobals(clientElements) {
g_o3dElement = clientElements[0];
g_o3d = g_o3dElement.o3d;
g_math = o3djs.math;
// Set window.g_client as well. Otherwise when the sample runs in
// V8, selenium won't be able to find this variable (it can only see
// the browser environment).
window.g_client = g_client = g_o3dElement.client;
// Create a pack to manage the objects created.
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);
}
/**
* Sets up reasonable view and projection matrices.
*/
function initContext() {
// Set up a perspective transformation for the projection.
g_viewInfo.drawContext.projection = g_math.matrix4.perspective(
g_math.degToRad(30), // 30 degree frustum.
g_client.width / g_client.height, // Aspect ratio.
1, // Near plane.
5000); // Far plane.
// Set up our view transformation to look towards the world origin where the
// cube is located.
g_viewInfo.drawContext.view = g_math.matrix4.lookAt(
[4, 4, 4], // eye
[0, 0, 0], // target
[0, 1, 0]); // up
}
/**
* Creates an effect using the shaders in the textarea in the document, applies
* the effect to a new material, binds the uniform parameters of the shader
* to parameters of the material, and sets certain parameters: the light and
* camera position.
* @return {Material} The material.
*/
function createMaterial() {
// Create a new, empty Material and Effect object.
var material = g_pack.createObject('Material');
var effect = g_pack.createObject('Effect');
// Load shader string from document.
var shaderString = o3djs.util.getElementContentById('effect');
effect.loadFromFXString(shaderString);
// Apply the effect to this material.
material.effect = effect;
// Bind uniform parameters declared in shader to parameters of material.
effect.createUniformParameters(material);
// Set the material's drawList.
material.drawList = g_viewInfo.performanceDrawList;
// Set light and camera positions for the pixel shader.
material.getParam('lightWorldPos').value = [3, 10, 0];
material.getParam('cameraWorldPos').value = [1, 3, 12];
// Look up clock param.
g_clockParam = material.getParam('clock');
return material;
}
/**
* Creates the plane using the primitives utility library, and adds it to the
* transform graph at the root node.
*/
function createPlane() {
// This will create a plane subdivided into 180,000 triangles.
var plane = o3djs.primitives.createPlane(
g_pack, createMaterial(), 4, 4, 300, 300);
// Add the shape to the transform heirarchy.
g_client.root.addShape(plane);
}
/**
* Updates the clock for the animation.
* @param {!o3d.RenderEvent} renderEvent Rendering Information.
*/
function onRender(renderEvent) {
var elapsedTime = renderEvent.elapsedTime;
// Update g_clock in the browser and cache a V8 copy that can be
// accessed efficiently. g_clock must be in the browser for selenium.
var clock = window.g_clock + elapsedTime * window.g_timeMult;
window.g_clock = clock;
g_clockParam.value = clock;
}
/**
* Cleanup before exiting.
*/
function unload() {
if (g_client) {
g_client.cleanup();
}
}
</script>
</head>
<body onload="init()" onunload="unload()">
<h1>Vertex Shader</h1>
This sample uses a custom vertex shader to quickly adjust the positions and
normals of many vertices in a plane to achieve a ripple effect without iterating
through the vertices in javascript.
<br/>
<!-- Start of O3D plugin -->
<div id="o3d" style="width: 600px; height: 600px;"></div>
<!-- End of O3D plugin -->
<!-- Text area to hold the shaders -->
<textarea id="effect" name="effect" cols="80" rows="20"
style="display: none;">
uniform float4x4 world : WORLD;
uniform float4x4 worldViewProjection : WORLDVIEWPROJECTION;
uniform float4x4 worldInverseTranspose : WORLDINVERSETRANSPOSE;
uniform float clock;
uniform float3 lightWorldPos;
uniform float3 cameraWorldPos;
// Input parameters for the vertex shader.
struct VertexShaderInput {
float4 position : POSITION;
float3 normal : NORMAL;
float4 color : COLOR;
};
// Input parameters for the pixel shader (also the output parameters for the
// vertex shader.)
struct PixelShaderInput {
float4 position : POSITION; // the position in clip space
float3 objectPosition : TEXCOORD0; // the position in world space
float3 normal : TEXCOORD1; // the normal in world space
float4 color : COLOR;
};
/**
* A function defining the shape of the wave. Takes a single float2 as an
* argument the entries of which are the x and z components of a point in the
* plane. Returns the height of that point.
*
* @param {float2} v The x and z components of the point in a single float2.
*/
float wave(float2 v) {
float d = length(v);
return 0.15 * sin(15 * d - 5 * clock) / (1 + d * d);
}
/**
* vertexShaderFunction - The vertex shader perturbs the vertices of the plane
* to achieve the ripples. Then it applies the worldViewProjection matrix.
*
* @param input.position Position vector of vertex in object coordinates.
* @param input.normal Normal of vertex in object coordinates.
* @param input.color Color of vertex.
*/
PixelShaderInput vertexShaderFunction(VertexShaderInput input) {
PixelShaderInput output;
float4 p = input.position;
// The height of the point p is adjusted according to the wave function.
p.y = wave(p.xz);
// Step size used to approximate the partial derivatives of the wave function.
float h = 0.001;
// We take the derivative numerically so that the wave function can be
// modified and the normal will still be correct.
float3 n = normalize(float3(
wave(float2(p.x - h, p.z)) - wave(float2(p.x + h, p.z)), 2 * h,
wave(float2(p.x, p.z - h)) - wave(float2(p.x, p.z + h))));
output.position = mul(p, worldViewProjection);
output.objectPosition = mul(p, world).xyz;
output.normal = mul(float4(n, 1), worldInverseTranspose).xyz;
output.color = input.color;
return output;
}
/**
* This pixel shader is meant to be minimal since the vertex shader is
* the focus of the sample.
*/
float4 pixelShaderFunction(PixelShaderInput input) : COLOR {
float3 p = input.objectPosition; // The point in question.
float3 l = normalize(lightWorldPos - p); // Unit-length vector toward light.
float3 n = normalize(input.normal); // Unit-length normal vector.
float3 v = normalize(cameraWorldPos - p); // Unit-length vector toward camera.
float3 r = normalize(-reflect(v, n)); // Reflection of v across n.
float3 q = (lightWorldPos - p);
float ldotr = dot(r, l);
float specular = clamp(ldotr, 0, 1) /
(1 + length(q - length(q) * ldotr * r));
return float4(0, 0.6, 0.7, 1) * dot(n, l) + specular;
}
// #o3d VertexShaderEntryPoint vertexShaderFunction
// #o3d PixelShaderEntryPoint pixelShaderFunction
// #o3d MatrixLoadOrder RowMajor
</textarea>
</body>
</html>
|
