Skip to content
Snippets Groups Projects
Commit e8f03e2b authored by luchen@google.com's avatar luchen@google.com
Browse files

o3d-webgl: Adding support for triangle fan/strip in picking. 

TEST=picking-more.html demo
Review URL: http://codereview.chromium.org/2805101

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55017 0039d316-1c4b-4281-b951-d872f2087c98
parent 97452c97
No related branches found
No related tags found
No related merge requests found
Hide whitespace changes
Inline Side-by-side
o3d/samples/o3d-webgl-samples/picking-more.html 0 → 100644
+ 384
− 0
View file @ e8f03e2b
<!--
Copyright 2010, 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
distribution.
* 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.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.
-->
<!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>
Picking and IndexBuffers
</title>
<script type="text/javascript" src="../o3d-webgl/base.js"></script>
<script type="text/javascript" src="../o3djs/base.js"></script>
<script type="text/javascript" id="o3dscript">
o3djs.base.o3d = o3d;
o3djs.require('o3djs.webgl');
o3djs.require('o3djs.math');
o3djs.require('o3djs.rendergraph');
o3djs.require('o3djs.primitives');
o3djs.require('o3djs.material');
o3djs.require('o3djs.picking');
// global variables
var g_o3dElement;
var g_client;
var g_o3d;
var g_math;
var g_pack;
var g_viewInfo;
var g_eyePosition = [0, 0, 10];
var g_dataroot;
var g_pickManager;
/**
* Creates the client area.
*/
function initClient() {
window.g_finished = false; // for selenium testing.
o3djs.webgl.makeClients(main);
}
/**
* Updates the span with the name of the shape that was picked, if anything.
* @param {event} e
*/
function pick(e) {
var worldRay = o3djs.picking.clientPositionToWorldRay(
e.x,
e.y,
g_viewInfo.drawContext,
g_client.width,
g_client.height);
var pickInfo = g_pickManager.pick(worldRay);
var picked = 'nothing';
if (pickInfo) {
picked = pickInfo.shapeInfo.shape.name;
}
document.getElementById('picked').innerHTML = picked;
}
/**
* Rotates the scene if key is one of 'wasd'.
* @param {event} event
*/
function rotateScene(event) {
// Ignore accelerator key messages.
if (event.metaKey)
return;
var keyChar = String.fromCharCode(o3djs.event.getEventKeyChar(event));
// Just in case they have capslock on.
keyChar = keyChar.toLowerCase();
var actionTaken = false;
var delta = 0.1;
switch(keyChar) {
case 'a':
g_dataroot.localMatrix =
g_math.matrix4.mul(g_dataroot.localMatrix,
g_math.matrix4.rotationY(-delta));
actionTaken = true;
break;
case 'd':
g_dataroot.localMatrix =
g_math.matrix4.mul(g_dataroot.localMatrix,
g_math.matrix4.rotationY(delta));
actionTaken = true;
break;
case 'w':
g_dataroot.localMatrix =
g_math.matrix4.mul(g_dataroot.localMatrix,
g_math.matrix4.rotationX(-delta));
actionTaken = true;
break;
case 's':
g_dataroot.localMatrix =
g_math.matrix4.mul(g_dataroot.localMatrix,
g_math.matrix4.rotationX(delta));
actionTaken = true;
break;
}
if (actionTaken) {
g_pickManager.update();
}
}
/**
* Initializes global variables, positions camera, draws shapes.
* @param {Array} clientElements Array of o3d object elements.
*/
function main(clientElements) {
// Init global variables.
initGlobals(clientElements);
// Set up the view and projection transformations.
initContext();
// Add the shapes to the transform heirarchy.
createShapes();
o3djs.event.addEventListener(g_o3dElement, 'mousedown', pick);
o3djs.event.addEventListener(g_o3dElement, 'keypress', rotateScene);
// Create the pick manager.
g_pickManager = o3djs.picking.createPickManager(g_client.root);
g_pickManager.update();
window.g_finished = true; // for selenium testing.
}
/**
* Initializes global variables and libraries.
*/
function initGlobals(clientElements) {
g_o3dElement = clientElements[0];
window.g_client = g_client = g_o3dElement.client;
g_o3d = g_o3dElement.o3d;
g_math = o3djs.math;
// Create a pack to manage the objects created.
g_pack = g_client.createPack();
// Creates a transform to put our data on.
g_dataroot = g_pack.createObject('Transform');
g_dataroot.parent = g_client.root;
g_dataroot.rotateY(-0.3);
// 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_o3dElement.clientWidth / g_o3dElement.clientHeight, // Aspect ratio.
1, // Near plane.
5000); // Far plane.
// Set up our view transformation to look towards the world origin where the
// primitives are located.
g_viewInfo.drawContext.view = g_math.matrix4.lookAt(
g_eyePosition, // eye
[0, 0, 0], // target
[0, 1, 0]); // up
}
/**
* Creates shapes using the primitives utility library, and adds them to the
* transform graph at the root node.
*/
function createShapes() {
var triangleFan = createShape(g_o3d.Primitive.TRIANGLEFAN);
triangleFan.name = 'triangle-fan';
var triangleStrip = createShape(g_o3d.Primitive.TRIANGLESTRIP);
triangleStrip.name = 'triangle-strip';
var triangleList = createShape(g_o3d.Primitive.TRIANGLELIST);
triangleList.name = 'triangle-list';
var noIndexBuffer = createShape(-1);
noIndexBuffer.name = 'bufferless';
// Add the shapes to the transforms.
var transformTable = [
{shape: noIndexBuffer, translation: [-0.5, 1.25, 0]},
{shape: triangleFan, translation: [-1.0, -1.0, 0]},
{shape: triangleStrip, translation: [1.0, -1.0, 0]},
{shape: triangleList, translation: [0, 0, 0]}
];
for (var tt = 0; tt < transformTable.length; ++tt) {
var transform = g_pack.createObject('Transform');
transform.addShape(transformTable[tt].shape);
transform.translate(transformTable[tt].translation);
transform.parent = g_dataroot;
}
}
/**
* Creates a shape that uses the requested indexing type.
* @param {o3d.Primitive.Type} indexType
*/
function createShape(indexType) {
var material = g_pack.createObject('Material');
var effect = g_pack.createObject('Effect');
var shaderString = document.getElementById('shader').value;
effect.loadFromFXString(shaderString);
material.effect = effect;
material.drawList = g_viewInfo.performanceDrawList;
effect.createUniformParameters(material);
var shape = g_pack.createObject('Shape');
var primitive = g_pack.createObject('Primitive');
var streamBank = g_pack.createObject('StreamBank');
primitive.material = material;
primitive.owner = shape;
primitive.streamBank = streamBank;
primitive.primitiveType = indexType;
primitive.createDrawElement(g_pack, null);
var positionArray = [];
switch (indexType) {
case g_o3d.Primitive.TRIANGLEFAN:
positionArray = [
0.5, 0.0, 0.5, // 0
0.5, 0.0, -0.5, // 1
-0.5, 0.0, -0.5, // 2
-0.5, 0.0, 0.5, // 3
0.0, -1.0, 0.0 // 4
];
indices = [4, 3, 2, 1, 0, 3]; // Square pyramid w/o the bottom.
primitive.numberPrimitives = 4;
primitive.numberVertices = 5;
break;
case g_o3d.Primitive.TRIANGLESTRIP:
positionArray = [
0.0, 0.0, 0.0, // 0
1.0, 0.0, 0.0, // 1
0.5, 0.0, -0.866, // 2
0.5, 0.866, -0.433 // 3
];
indices = [0, 1, 3, 2, 0, 1]; // Triangular pyramid sort of shape.
primitive.numberPrimitives = 4;
primitive.numberVertices = 4;
break;
case g_o3d.Primitive.TRIANGLELIST:
positionArray = [
-0.5, -0.5, 0.5, // vertex 0
0.5, -0.5, 0.5, // vertex 1
-0.5, 0.5, 0.5, // vertex 2
0.5, 0.5, 0.5, // vertex 3
-0.5, 0.5, -0.5, // vertex 4
0.5, 0.5, -0.5, // vertex 5
-0.5, -0.5, -0.5, // vertex 6
0.5, -0.5, -0.5 // vertex 7
];
indices = [
0, 1, 2, // face 1
2, 1, 3,
2, 3, 4, // face 2
4, 3, 5,
4, 5, 6, // face 3
6, 5, 7,
6, 7, 0, // face 4
0, 7, 1,
1, 7, 3, // face 5
3, 7, 5,
6, 0, 4, // face 6
4, 0, 2
];
primitive.numberPrimitives = 12;
primitive.numberVertices = 8;
break;
default:
// No index buffer. Vertex data contains triples of triangles.
positionArray = [
-0.5, -0.5, 0.5,
0.5, -0.5, 0.5,
-0.5, 0.5, 0.5,
0.5, -0.5, 0.5,
1.5, -0.5, 0.5, // vertex 1
1.5, 0.5, 0.5 // vertex 3
];
indices = null;
primitive.numberPrimitives = 2;
primitive.numberVertices = 6;
break;
}
// Create buffers containing the vertex data.
var positionsBuffer = g_pack.createObject('VertexBuffer');
var positionsField = positionsBuffer.createField('FloatField', 3);
positionsBuffer.set(positionArray);
if (indices) {
var indexBuffer = g_pack.createObject('IndexBuffer');
indexBuffer.set(indices);
primitive.indexBuffer = indexBuffer;
}
// Associate the positions Buffer with the StreamBank.
streamBank.setVertexStream(
g_o3d.Stream.POSITION, // semantic: This stream stores vertex positions
0, // semantic index: First (and only) position stream
positionsField, // field: the field this stream uses.
0); // start_index: How many elements to skip in the
// field.
return shape;
}
</script>
</head>
<body onload="initClient()">
<h1>More Picking</h1>
<p>This example demonstrates picking with custom shapes that use a variety of
index buffer formats. Back faces are culled (hidden) and cannot be picked.</p>
<p>
You picked: <span id="picked" style="color: red;">nothing</span>
</p>
<p>Rotate in the scene with WASD.</p>
<br/>
<!-- Start of O3D plugin -->
<div id="o3d" style="width: 600px; height: 600px;"></div>
<!-- End of O3D plugin -->
<textarea id="shader" style="display: none;">
attribute vec4 position;
uniform mat4 worldViewProjection;
varying vec4 pos;
/**
* The vertex shader simply transforms the input vertices to screen space.
*/
void main() {
// Multiply the vertex positions by the worldViewProjection matrix to
// transform them to screen space.
gl_Position = worldViewProjection * position;
pos = position;
}
// #o3d SplitMarker
varying vec4 pos;
/**
* The fragment shader derives color based on the position.
*/
void main() {
gl_FragColor = vec4(pos.xyz, 1.0);
}
</textarea>
</body>
</html>
o3d/samples/o3d-webgl/primitive.js
+ 57
− 7
View file @ e8f03e2b
......@@ -333,6 +333,44 @@ o3d.Primitive.prototype.computeWireframeIndices_ = function() {
}
};
/**
* Returns the three indices of the n-th triangle of this primitive. If the
* primitive has no index buffer, then the buffer is assumed to be [0 ... n-1].
* These indices can then be used to reference the vertex buffer and get the
* triangle vertices' positions.
*
* @param {number} n The number of the triangle we want. Zero-indexed.
* @return {!Array.<Number>} Array containing three indices that correspond to
* the n-th triangle of this primitive.
* @private
*/
o3d.Primitive.prototype.computeTriangleIndices_ = function(n) {
var indices;
switch (this.primitiveType) {
case o3d.Primitive.TRIANGLESTRIP:
if (n % 2 == 0) {
indices = [n, n + 1, n + 2];
} else {
indices = [n + 1, n, n + 2];
}
break;
case o3d.Primitive.TRIANGLEFAN:
indices = [0, n + 1, n + 2];
break;
case o3d.Primitive.TRIANGLELIST:
default:
indices = [3 * n, 3 * n + 1, 3 * n + 2];
break;
}
if (this.indexBuffer) {
var buffer = this.indexBuffer.array_;
return [buffer[indices[0]],
buffer[indices[1]],
buffer[indices[2]]];
} else {
return indices;
}
};
/**
* Computes the intersection of a ray in the coordinate system of
......@@ -392,15 +430,27 @@ o3d.Primitive.prototype.intersectRay =
// from the start the point with this variable.
var min_distance = 0;
// Iterate through the indices three at a time. Each triple of indices
// defines a triangle. For each triangle, we test for intersection with
// Iterate through the indices and examine triples of indices that each
// define a triangle. For each triangle, we test for intersection with
// the ray. We need to find the closest one to start, so we have to
// check them all.
var a = indexBuffer.array_;
for (var i = 0; i < a.length / 3; ++i) {
// Indices of the triangle.
var t = 3 * i;
var indices = [a[t], a[t + 1], a[t + 2]];
var numIndices = indexBuffer ? indexBuffer.array_.length : numPoints;
switch (this.primitiveType) {
case o3d.Primitive.TRIANGLESTRIP:
numTriangles = numIndices - 2;
break;
case o3d.Primitive.TRIANGLEFAN:
numTriangles = numIndices - 2;
break;
case o3d.Primitive.TRIANGLELIST:
default:
numTriangles = numIndices / 3;
break;
}
for (var i = 0; i < numTriangles; ++i) {
var indices = this.computeTriangleIndices_(i);
// Check if the current triangle is too far to one side of the ray
// to intersect at all. (This is what the orthogonal vectors are for)
......
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment