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<!--
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<!--
O3D Tutorial B4
This tutorial shows how we generate a simple cube mesh
and view it using a dynamically generated camera which can be animated.
We also show how to dynamically change the perspective matrix
to adjust to the correct aspect ratio as the o3d window is resized.
The cube can be animated along the target's y-axis and the animation is
done every time a frame is rendered.
-->
<!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>
Tutorial B4: Cameras and events
</title>
<style type="text/css">
html, body {
height: 100%;
margin: 0;
padding: 0;
border: none;
}
</style>
<!-- Our javascript code -->
<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.material');
// Events
// Run the init() function once the page has finished loading.
// unload() when the page is unloaded.
window.onload = init;
window.onunload = unload;
// global variables
var g_o3d;
var g_math;
var g_client;
var g_pack;
var g_viewInfo;
var g_o3dElement;
var g_o3dWidth = -1;
var g_o3dHeight = -1;
// Our view and projection matrices
// The view matrix transforms objects from world space to view space.
var g_viewMatrix;
// The projection matrix projects objects from view space to the screen.
var g_projMatrix;
// Animation varibles
// Boolean flag that signals whether animation is on.
var g_animate;
// Current angle
var g_animateAngle;
/**
* Creates our client area by looking for <div>s with an id that starts with
* "o3d".
*/
function init() {
o3djs.util.makeClients(initStep2);
}
/**
* Initializes O3D, loads the effect, and draws the cube.
* @param {Array} clientElements Array of o3d object elements.
*/
function initStep2(clientElements) {
// Initialize global variables and libraries.
g_o3dElement = clientElements[0];
g_o3d = g_o3dElement.o3d;
g_math = o3djs.math;
g_client = g_o3dElement.client;
// Create 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);
// Reset animation variables.
g_animate = false;
g_animateAngle = 0;
// Create a material.
var myMaterial = o3djs.material.createMaterialFromFile(
g_pack,
'shaders/vertex-color.shader',
g_viewInfo.performanceDrawList);
// Create a cube.
var cube = o3djs.primitives.createRainbowCube(g_pack, myMaterial, 1);
setDefaultCameraValues();
setCamera();
// Generate the projection and viewProjection matrices based
// on the plugin size by calling Resize().
resize();
// Attach the cube to the root of the transform graph.
var root = g_client.root;
root.addShape(cube);
// Set our render callback for animation.
// This sets a function to be executed every time a frame is rendered.
g_client.setRenderCallback(onrender);
}
// Generates the projection matrix based on the size of the g_o3d plugin
// and calculates the view-projection matrix.
function resize() {
var newWidth = g_client.width;
var newHeight = g_client.height;
if (newWidth != g_o3dWidth || newHeight != g_o3dHeight) {
g_o3dWidth = newWidth;
g_o3dHeight = newHeight;
// Create our projection matrix, with a vertical field of view of 45 degrees
// a near clipping plane of 0.1 and far clipping plane of 100.
g_projMatrix = g_math.matrix4.perspective(
g_math.degToRad(45),
g_o3dWidth / g_o3dHeight,
0.1,
100);
// update our view projection matrix
setViewProjection();
}
}
// Sets the view and projection matrices.
function setViewProjection() {
g_viewInfo.drawContext.view = g_viewMatrix;
g_viewInfo.drawContext.projection = g_projMatrix;
}
// Sets the default camera values and updates the view matrix
function setDefaultCameraValues() {
var myForm = document.defaultForm;
// default eye position = (2, 2, 4)
myForm.eyeX.value = '2.0';
myForm.eyeY.value = '1.0';
myForm.eyeZ.value = '4.0';
// default target position = (0, 0, 0)
// (ie centre of the cube)
myForm.targetX.value = '0.0';
myForm.targetY.value = '0.0';
myForm.targetZ.value = '0.0';
// default up vector = (0, 1, 0)
// (this tells the renderer which direction is 'up')
// in this case, we define the positive y-axis to be 'up'.
myForm.upX.value = '0.0';
myForm.upY.value = '1.0';
myForm.upZ.value = '0.0';
// update the view matrix
setCamera();
}
// Updates the view matrix using the current camera parameters
function setCamera() {
// Create our view matrix using the target, eye, and up vectors in the form
// and using the lookAt(..)
// helper function to create the matrix.
var myForm = document.defaultForm;
// Eye-position, this is where our camera is at.
var eye = [parseFloat(myForm.eyeX.value),
parseFloat(myForm.eyeY.value),
parseFloat(myForm.eyeZ.value)];
// Target, this is where our camera is pointed at.
var target = [parseFloat(myForm.targetX.value),
parseFloat(myForm.targetY.value),
parseFloat(myForm.targetZ.value)];
// Up-vector, this tells the camera which direction is 'up'.
// We define the positive y-direction to be up in this example.
var up = [parseFloat(myForm.upX.value),
parseFloat(myForm.upY.value),
parseFloat(myForm.upZ.value)];
g_viewMatrix = g_math.matrix4.lookAt(eye, target, up);
// if we already have our projection matrix,
// update the view projection matrix.
if (g_projMatrix)
setViewProjection();
}
// Validates a field in the form to make sure it contains a float.
function validateFloat(field) {
var floatValue = parseFloat(field.value);
if (isNaN(floatValue))
field.value = '0.0';
else
field.value = floatValue;
}
// Toggles animation
function toggleAnimate() {
// toggle the animate flag.
g_animate = !g_animate;
if (g_animate) {
// turn on animation
document.defaultForm.btnAnimate.value = 'Stop animation';
} else {
// turn off animation
document.defaultForm.btnAnimate.value = 'Animate';
}
}
// Animates the camera.
// This function executes on each frame.
// It was set using g_client.setRenderCallback(..)
// in initStep2().
function onrender(renderEvent) {
resize();
if (g_animate) {
// Update the angle frame rate independently.
g_animateAngle += 2.0 * renderEvent.elapsedTime;
var myForm = document.defaultForm;
// Set radius to 1.5
var radius = 1.5;
// rotate around the y-axis relative to the target
myForm.eyeX.value = parseFloat(myForm.targetX.value) +
Math.sin(g_animateAngle) * radius;
myForm.eyeZ.value = parseFloat(myForm.targetZ.value) +
Math.cos(g_animateAngle) * radius;
setCamera();
}
}
/**
* Removes any callbacks so they don't get called after the page has unloaded.
*/
function unload() {
if (g_client) {
g_client.cleanup();
}
}
</script>
</head>
<body>
<table width="100%" style="height:100%;"><tr><td valign="middle" align="center">
<table width="100%" style="height:100%;"><tr><td>
<h1>Cameras and events</h1>
<p>
This tutorial shows how we generate a simple cube mesh
and view it using a dynamically generated camera which can be animated.
</p>
<p>
Press Animate to animate the camera and use the textboxes to manually
set the position of the camera.
</p>
<!-- Centre everything in the div -->
<table id="container" width="98%" style="height:50%;"><tr><td height="100%">
<!-- Start of g_o3d plugin -->
<div id="o3d" style="width: 100%; height: 100%;"></div>
<!-- End of g_o3d plugin -->
</td></tr></table>
<!-- Format input fields nicely in a table -->
<form action="#" method="get" name="defaultForm">
<table style="margin-left:auto; margin-right:auto"
summary="This table contains camera controls.">
<thead style="font-weight:bold; text-align:center">
<tr>
<th></th>
<th>x</th>
<th>y</th>
<th>z</th>
<th></th>
</tr>
</thead>
<tbody>
<tr>
<td>Eye</td>
<td><input name="eyeX"
type="text"
onblur="validateFloat(this)"/></td>
<td><input name="eyeY"
type="text"
onblur="validateFloat(this)"/></td>
<td><input name="eyeZ"
type="text"
onblur="validateFloat(this)"/></td>
<td rowspan="2">
<input name="btnSet"
type="button"
value="Set camera"
onClick="setCamera()"/>
</td>
</tr>
<tr>
<td>Target</td>
<td><input name="targetX"
type="text"
onblur="validateFloat(this)"/></td>
<td><input name="targetY"
type="text"
onblur="validateFloat(this)"/></td>
<td><input name="targetZ"
type="text"
onblur="validateFloat(this)"/></td>
</tr>
<tr>
<td>Up vector</td>
<td><input name="upX"
type="text"
onblur="validateFloat(this)"/></td>
<td><input name="upY"
type="text"
onblur="validateFloat(this)"/></td>
<td><input name="upZ"
type="text"
onblur="validateFloat(this)"/></td>
<td>
<input name="btnDefault"
type="button"
value="Restore default camera"
onClick="setDefaultCameraValues()"/>
</td>
</tr>
<tr>
<td colspan="5" style="text-align:center">
<input name="btnAnimate"
type="button"
value="Animate"
onClick="toggleAnimate()"/>
</td>
</tr>
</tbody>
</table>
</form>
</td></tr></table>
</td></tr></table>
</body>
</html>
|
