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yuv2rgb.html
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yuv2rgb.html
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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
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.
-->
<!--
O3D YUV to RGB conversion Tutorial
In this sample we convert from a Y'UV420p encoded video frame to an
RGB texture using a shader to do the conversion on the video hardware.
-->
<!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>YUV to RGB Conversion in a shader.</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.util');
o3djs.require('o3djs.math');
o3djs.require('o3djs.rendergraph');
o3djs.require('o3djs.primitives');
o3djs.require('o3djs.material');
o3djs.require('o3djs.io');
// Events
// Run the init() once the page has finished loading.
window.onload = init;
// global variables
var g_o3d;
var g_math;
var g_client;
var g_pack;
var g_viewInfo;
var g_finished = false; // for selenium testing
/**
* Creates the client area and sets up the secondary init entry point.
*/
function init() {
o3djs.webgl.makeClients(initStep2);
}
/**
* Initializes O3D, loads the effect, and draws the quad that
* will display the texture.
*
* @param {Array} clientElements Array of o3d object elements.
*/
function initStep2(clientElements) {
// Initialize global variables and libraries.
var o3dElement = clientElements[0];
g_o3d = o3dElement.o3d;
g_math = o3djs.math;
g_client = 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);
// Setup an orthographic projection
// Offset by half a pixel to avoid roundoff errors.
g_viewInfo.drawContext.projection = g_math.matrix4.orthographic(
-g_client.width * 0.5 + 0.5,
g_client.width * 0.5 + 0.5,
-g_client.height * 0.5 - 0.5,
g_client.height * 0.5 - 0.5,
0.1,
1000);
g_viewInfo.drawContext.view = g_math.matrix4.lookAt(
[0, 500, 0],
[0, 0, 0],
[0, 0, -1]);
// Create a material.
var myMaterial = o3djs.material.createMaterialFromFile(
g_pack,
'../shaders/yuv2rgb-glsl.shader',
g_viewInfo.performanceDrawList);
// Creates a quad using the effect that has a 1:1 aspect ratio.
var myShape = o3djs.primitives.createPlane(g_pack,
myMaterial,
720, // width
720, // height
1, // quads across
1); // quads down
// Get the material's sampler parameter
var sampler_param = myMaterial.getParam('textureSampler');
var sampler = g_pack.createObject('Sampler');
sampler.addressModeU = g_o3d.Sampler.WRAP;
sampler.addressModeV = g_o3d.Sampler.WRAP;
sampler.magFilter = g_o3d.Sampler.POINT;
sampler.minFilter = g_o3d.Sampler.POINT;
// Be sure to turn off MIP-mapping, since that causes problems when
// jumping around the image the way we are.
sampler.mipFilter = g_o3d.Sampler.NONE;
sampler_param.value = sampler;
// Set the source image width
var width_param = myMaterial.getParam('imageWidth');
width_param.value = 720.0;
// Set the source image height
var height_param = myMaterial.getParam('imageHeight');
height_param.value = 486.0;
// Load our Y'UV420p texture, encoded as a greyscale PNG image. This
// happens asynchronously.
var url = o3djs.util.getCurrentURI() + '../assets/shaving_cream.png';
o3djs.io.loadTexture(g_pack, url, function(texture, exception) {
if (exception) {
alert(exception);
return;
}
sampler.texture = texture;
// adjust the scale of our transform to match the aspect ratio of
// the texture. Of course we could also have waited until now to build
// our quad and set its width and height to match instead of scaling
// here.
var textureWidth = texture.width;
// Account for additional data on bottom of image.
var textureHeight = texture.height * 2.0 / 3.0;
var hScale = 1;
var vScale = 1;
if (textureWidth > textureHeight) {
vScale = textureHeight / textureWidth;
} else if (textureHeight > textureWidth) {
hScale = textureWidth / textureHeight;
}
// We now attach our quad to the root of the transform graph. We do
// this after the texture has loaded, otherwise we'd be attempting
// to display something invalid.
var root = g_client.root;
root.addShape(myShape);
root.scale(hScale, 1, vScale);
g_finished = true; // for selenium testing.
});
}
</script>
</head>
<body>
<h1>YUV to RGB Conversion</h1>
<p>This how to do image colorspace and format conversion in a shader.</p>
<p>Here is the YUV encoded image (treated as an 8-bit greyscale image):</p>
<p><img src="../assets/shaving_cream.png" style="width: 720px; height: 729px"
alt="YUV encoded image"/></p>
<p>Here is the original image, encoded as a JPEG image:</p>
<p><img src="../assets/shaving_cream.jpg" style="width: 720px; height: 486px"
alt="Original JPG encoded image"/></p>
<p>Here is the O3D plugin loading the YUV image, and converting it
to RGB in the shader on the fly.</p>
<p>Note: With O3D-WebGL, we cannot get an exact translation back to the original
image due to WebGL behavior that does not occur in the plugin. See shader for
more details.</p>
<!-- Start of O3D plugin -->
<div id="o3d" style="width: 720px; height: 486px"></div>
<!-- End of O3D plugin -->
</body>
</html>