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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.
-->
<!--
Sample demonstrating drawing into a Canvas surface using an O3D texture.
-->
<!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>
O3D Canvas
</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.io');
o3djs.require('o3djs.math');
o3djs.require('o3djs.canvas');
o3djs.require('o3djs.rendergraph');
// Events
// init() once the page has finished loading.
// unload() when the page is unloaded.
window.onload = createClients;
window.onunload= unload;
// Globals
var g_o3d;
var g_math;
var g_client;
var g_pack;
var g_viewInfo;
var g_brushTexture;
var g_canvasQuad;
var g_o3dElement;
var g_finished = false; // for selenium testing.
var g_canvasWidth = 700;
var g_canvasHeight = 500;
var g_borderWidth = 50;
var g_borderHeight = 50;
var g_clientWidth;
var g_clientHeight;
/**
* Remove any callbacks so they don't get called after the page has unloaded.
*/
function unload() {
if (g_client) {
g_client.cleanup();
// Clear the mouse events.
onMouseUp();
}
}
function createClients() {
o3djs.util.makeClients(init);
}
/**
* This method gets called on a mouse move event. If the mouse cursor is inside
* the canvas quad then it draws a copy of the brush texture onto the canvas
* surface at the mouse cursor position.
* @param e The mouse move event object
*/
function drawCursor(e) {
if (!g_brushTexture)
return;
var offset = {
x: e.x / g_client.width * g_clientWidth,
y: e.y / g_client.height * g_clientHeight
};
// Adjust for the top left corner of the canvas.
offset.x -= g_borderWidth;
offset.y -= g_borderHeight;
// Setting brushScale to a value other than 1 will draw a scaled copy of
// the brush bitmap onto the canvas surface. This is achieved by applying
// a scale transformation before calling drawBitmap(), and restoring the
// draw matrix immediately after.
var brushScale = 1;
if (offset.x >= 0 && offset.x < g_canvasWidth &&
offset.y >= 0 && offset.y < g_canvasHeight) {
g_canvasQuad.canvas.saveMatrix();
g_canvasQuad.canvas.scale(brushScale, brushScale);
// Note that the coordinates passed to drawBitmap get scaled by the current
// canvas drawing matrix and therefore we adjust them by the scale to get
// the bitmap to follow the mouse position.
g_canvasQuad.canvas.drawBitmap(
g_brushTexture,
(offset.x / brushScale - g_brushTexture.width * 0.5),
(offset.y / brushScale + g_brushTexture.height * 0.5));
g_canvasQuad.canvas.restoreMatrix();
g_canvasQuad.updateTexture();
}
}
/**
* Fetches the bitmap pointed to by the URL supplied by the user, creates
* an O3D Texture object with it, and resets the value of g_brushTexture
* to point to the newly created texture.
*/
function changeBrushTexture() {
var textureUrl = document.getElementById('url').value;
o3djs.io.loadTexture(g_pack, textureUrl, function(texture, exception) {
// Remove the previous brush texture from the pack.
if (exception) {
alert(exception);
} else {
if (g_brushTexture) {
g_pack.removeObject(g_brushTexture);
}
g_brushTexture = texture;
}
});
}
/**
* Event handler that gets called when a mouse click takes place in the
* O3D element. It registers a callback for mousemove which handles
* drawing and one for mouseup which removes the mousemove event.
* @param e The mouse down event.
*/
function onMouseDown(e) {
o3djs.event.addEventListener(g_o3dElement, 'mousemove', drawCursor);
o3djs.event.addEventListener(g_o3dElement, 'mouseup', onMouseUp);
// Draw the cursor at the clicked spot.
drawCursor(e);
}
/**
* Event handler for mouse up. It clears the mouse move and mouse up event
* handlers.
*/
function onMouseUp() {
o3djs.event.removeEventListener(g_o3dElement, 'mousemove', drawCursor);
o3djs.event.removeEventListener(g_o3dElement, 'mouseup', onMouseUp);
}
function init(clientElements) {
// Initializes global variables and libraries.
var o3dElement = clientElements[0];
g_o3dElement = o3dElement;
g_o3d = o3dElement.o3d;
g_math = o3djs.math;
g_client = o3dElement.client;
// Store the size of the plugin, so that we can adjust coordinates in
// full-screen mode. This is necessary because we're not adjusting the aspect
// ratio; we'd rather that the canvas filled the available area, rather than
// staying a fixed size or aspect ratio.
g_clientWidth = g_o3dElement.clientWidth;
g_clientHeight = g_o3dElement.clientHeight;
// Set the texture URL.
var path = window.location.href;
var index = path.lastIndexOf('/');
path = path.substring(0, index+1) + 'assets/brush.png';
var url = document.getElementById("url").value = path;
// Creates a pack to manage our resources/assets
g_pack = g_client.createPack();
g_viewInfo = o3djs.rendergraph.createBasicView(
g_pack,
g_client.root,
g_client.renderGraphRoot);
// Set the background color to blue.
g_viewInfo.clearBuffer.clearColor = [0.5, 0.1, 1, 1];
// Setup an orthographic projection camera.
g_viewInfo.drawContext.projection = g_math.matrix4.orthographic(
0 + 0.5,
g_client.width + 0.5,
g_client.height + 0.5,
0 + 0.5,
0.001,
1000);
g_viewInfo.drawContext.view = g_math.matrix4.lookAt(
[0, 0, 1], // Eye.
[0, 0, 0], // Target.
[0, 1, 0]); // Up.
// Creates an instance of the canvas utilities library.
var canvasLib = o3djs.canvas.create(g_pack, g_client.root, g_viewInfo);
// Create a canvas surface to draw on.
var canvasQuad =
canvasLib.createXYQuad(g_borderWidth, g_borderHeight, 0, g_canvasWidth,
g_canvasHeight, false);
canvasQuad.canvas.clear([1, 0, 0, 1]);
canvasQuad.updateTexture();
// Set the initial brush texture.
changeBrushTexture();
// Setup the events to track mouse activity.
o3djs.event.addEventListener(o3dElement, 'mousedown', onMouseDown);
g_canvasQuad = canvasQuad;
g_finished = true; // for selenium testing.
}
</script>
</head>
<body>
<h1>O3D Canvas Sample: Drawing with bitmaps</h1>
<br/>
<!-- Start of O3D plugin -->
<div id="o3d" style="width: 800px; height: 600px;"></div>
<!-- End of O3D plugin -->
<p><p>
Brush URL: <input type="text" id="url" size="100">
<input type="button" onclick="changeBrushTexture();" value="Change Brush"><BR>
<p><p>Click and drag to draw onto the red canvas surface.
</body>
</html>
|
