Displacement of a 3D mesh
A heightmap is used in an AGAL fragment shader to simulate shading of a lower zones.
package
{
import com.adobe.utils.AGALMiniAssembler;
import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.display.Shape;
import flash.display.Sprite;
import flash.display.Stage3D;
import flash.display.StageAlign;
import flash.display.StageQuality;
import flash.display.StageScaleMode;
import flash.display3D.Context3D;
import flash.display3D.Context3DProfile;
import flash.display3D.Context3DProgramType;
import flash.display3D.Context3DRenderMode;
import flash.display3D.Context3DTextureFormat;
import flash.display3D.Context3DVertexBufferFormat;
import flash.display3D.IndexBuffer3D;
import flash.display3D.Program3D;
import flash.display3D.textures.Texture;
import flash.display3D.VertexBuffer3D;
import flash.events.Event;
import flash.events.KeyboardEvent;
import flash.events.MouseEvent;
import flash.events.TouchEvent;
import flash.geom.Matrix;
import flash.geom.Matrix3D;
import flash.geom.Vector3D;
import flash.text.TextField;
import flash.text.TextFieldAutoSize;
import flash.ui.Keyboard;
import flash.ui.Multitouch;
import flash.ui.MultitouchInputMode;
import flash.utils.getTimer;
public class Main extends Sprite
{
private var _cameraRotation:Vector3D = new Vector3D(-320, -5, 0);
private var _cameraRadius:Number = 150;
private var _mousePos2d:Vector3D;
private var _texture:BitmapData;
private var _mx:Matrix3D = new Matrix3D();
private var _verts:Vector.<Number>; //xyzuvnnn, xyzuvnnn, ... (stride=8)
private var _vStride:uint = 8;
private var _indices:Vector.<uint>;
private var _rotTime:int;
private var _HQ:Boolean = true;
private var _ctx3d:Context3D;
private var _shaders:Program3D;
private var _iBuf:IndexBuffer3D;
private var _vBuf:VertexBuffer3D;
private var _viewMx:Matrix3D;
private var _projMx:Matrix3D;
private var _diffTex:Texture;
private var _camPos:Vector3D;
private var _lightPos:Vector3D = new Vector3D(-100, 100, -100);
private var _ambient:Number = .2;
private var _needsSnapshot:Boolean = false;
private var _snapshot:Bitmap;
private var _brush:Vector3D = new Vector3D();
private var _t:Number = 0;
private var _dangle:Number = .005;
private var _terrainW:Number = 100;
private var _terrainH:Number = 100;
private var _terrainStepsW:uint = 127;
private var _terrainStepsH:uint = 127;
private var _hmap:PerlinHeightMap;
private var _hmapHolder:Bitmap;
private var _bumpTex:Texture;
public function Main():void
{
trace('initializing stage 2d ...');
if (stage) init();
else addEventListener(Event.ADDED_TO_STAGE, init);
}
private function init(e:Event = null):void
{
removeEventListener(Event.ADDED_TO_STAGE, init);
// entry point
prepare2dStage();
requestContext3DOf2dStage();
initInteractivity();
}
private function prepare2dStage():void {
stage.frameRate = 60;
stage.scaleMode = StageScaleMode.NO_SCALE;
stage.align = StageAlign.TOP_LEFT;
stage.quality = qualitySettings(StageQuality.LOW, StageQuality.HIGH);
trace('stage 2d is ready!');
}
/// block 3d ///
private function requestContext3DOf2dStage():void {
trace('creating context 3d ...');
stage.stage3Ds[0].addEventListener(Event.CONTEXT3D_CREATE, onContext3DCreate);
stage.stage3Ds[0].requestContext3D(Context3DRenderMode.AUTO, Context3DProfile.BASELINE);
}
private function onContext3DCreate(e:Event):void {
_ctx3d = (e.target as Stage3D).context3D;
if (!_ctx3d) {
trace('Error: can\'t obtain context 3d!');
return;
} else {
trace('context 3d created!');
}
initContet3D();
initShaders();
initMesh();
initPerlinTerrain();
// add keyboard handlers
stage.addEventListener(KeyboardEvent.KEY_UP, keyboardHandler);
// start rendering
stage.addEventListener(Event.ENTER_FRAME, onEnterFrame);
}
private function initContet3D():void {
// debug
_ctx3d.enableErrorChecking = true;
// handle resizing of a viewport
stage.addEventListener(Event.RESIZE, onResize);
onResize();
}
private function onResize(e:Event = null):void {
_ctx3d.configureBackBuffer(stage.stageWidth, stage.stageHeight, qualitySettings(0, 4), true, false);
}
private function initShaders():void {
// vertex shader which does a 3d transformation of a model
var vs:String =
"m44 op, va0, vc0" + "\n" + // OutputPosition(op) = xyz(vt0) * transformMatrix(vc0)
"mov v0, va0" + "\n" + // va0 = xyz, put it as v0
"mov v1, va1" + "\n" + // va1 = uv, put it to FS as v1
"mov v2, va2" + "\n" + // v2 = normal's xyz(va2)
"sub v3, vc4, va0"; // v3 = "light's direction" = "light's position"(vc4) - "current vertex"(va0)
var vsa:AGALMiniAssembler = new AGALMiniAssembler();
vsa.assemble(Context3DProgramType.VERTEX, vs);
var texFlags:String = qualitySettings("<2d>", "<2d,linear>");
// fragment shader to render a model
/*var fs:String =
"tex ft0, v1, fs0 " + texFlags + "\n" + // take the texture color from texture(fs0) in uv(v1), <2d,linear,miplinear>
"mov oc, ft0" + "\n"; // color to OutputColor(oc)*/
var fs:String =
"tex ft0, v1, fs0 " + texFlags + "\n" + // take the texture color from texture(fs0) in uv(v1), <2d,linear,miplinear>
/*"nrm ft1.xyz, v2" + "\n" + // ft1 = norm(n), v2=n. make sure, that n is a unit vector
"nrm ft2.xyz, v3" + "\n" + // ft2 = norm(lightDirection), lightDirection=v3
"dp3 ft3.x, ft1.xyz, ft2.xyz" + "\n" + // ft3.x = dot(n, lightDirection)
"max ft3.x, ft3.x, fc1.x" + "\n" + // ft3.x > 0 !
"add ft3, ft3.x, fc0" + "\n" + // ft3 += ambient(fc0.xyz)
"mul ft0, ft0, ft3" + "\n" + // color *= ft3
//"mov oc, v2"; // draw a normal
"mov oc, ft0"; // color to OutputColor(oc)*/
"tex ft1, v1, fs1 <2d,linear>" + "\n" + // ft1 = heightmap[0,0], rgb = hhh
"add ft1.xyz, ft1.xyz, fc0.xyz" + "\n" + // ft1 += ambient(fc0.xyz)
"mul ft0, ft0, ft1" + "\n" +
"mov oc, ft0";
var fsa:AGALMiniAssembler = new AGALMiniAssembler();
fsa.assemble(Context3DProgramType.FRAGMENT, fs);
// combine shaders into a single program ready to be uploaded to GPU
_shaders = _ctx3d.createProgram();
_shaders.upload(vsa.agalcode, fsa.agalcode)
}
private function initMesh():void {
// read a raw data
readModel();
// indices
_iBuf = _ctx3d.createIndexBuffer(_indices.length); // total amount of vertices forming the triandles
_iBuf.uploadFromVector(_indices, 0, _indices.length);
// vertices
_vBuf = _ctx3d.createVertexBuffer(_verts.length / _vStride, _vStride);
_vBuf.uploadFromVector(_verts, 0, _verts.length / _vStride);
// textures
_diffTex = createTexture(_texture);
}
private function createTexture(bd:BitmapData, mip:Boolean = true):Texture {
var mipMap:BitmapData = bd;
var tex:Texture = _ctx3d.createTexture(bd.width, bd.height, Context3DTextureFormat.BGRA, false);
var mipLevel:int = 0;
tex.uploadFromBitmapData(bd, mipLevel++);
if (mip) {
// create mipmaps
while (bd.width > 1 || bd.height > 1) {
mipMap = new BitmapData(Math.max(1, bd.width >> 1), Math.max(1, bd.height >> 1), true, 0);
mipMap.draw(bd, new Matrix(0.5, 0, 0, 0.5, 0, 0), null, null, null, true);
tex.uploadFromBitmapData(mipMap, mipLevel++);
bd = mipMap;
}
}
return tex;
}
private function onEnterFrame(e:Event):void {
updatePerlin();
//autoRotate();
updateCamera();
render();
}
private function updateCamera():void {
trace(_cameraRotation);
_mx = new Matrix3D();
_viewMx = viewMatrix(_cameraRotation, _cameraRadius, 0);
_projMx = projMatrix(45, stage.stageWidth / stage.stageHeight, 0.1, 1000);
// multiply matrices
_mx.append(_viewMx);
_mx.append(_projMx);
// camera's position
_viewMx.invert();
_camPos = _viewMx.position;
}
private function autoRotate():void {
// update camera
if (!_mousePos2d) {
_cameraRotation.y += _dangle * 180 / Math.PI;
}
}
private function render():void {
if (!_ctx3d) return;
_lightPos = _camPos;
// init renderer for the new frame
//_ctx3d.setDepthTest(true, Context3DCompareMode.LESS_EQUAL);
//_ctx3d.setCulling(Context3DTriangleFace.FRONT);
_ctx3d.clear(.5, .5, .5);
// upload shaders
_ctx3d.setProgram(_shaders);
// upload constants
// vertex
_ctx3d.setProgramConstantsFromMatrix(Context3DProgramType.VERTEX, 0, _mx, true); // vc0 = a 4x4 transform matrix -> 4 registers (vc0-vc3)
_ctx3d.setProgramConstantsFromVector(Context3DProgramType.VERTEX, 4, Vector.<Number>([_lightPos.x, _lightPos.y, _lightPos.z, 0.0])); // vc4 = light's position
_ctx3d.setProgramConstantsFromVector(Context3DProgramType.VERTEX, 5, Vector.<Number>([_brush.x, _brush.y, _brush.z, _brush.w])); // vc5 = brush position (x,y=h,z, w = r^2)
// fragment
_ctx3d.setProgramConstantsFromVector(Context3DProgramType.FRAGMENT, 0, Vector.<Number>([_ambient, _ambient, _ambient, 1.0])); // fc0 = ambient
_ctx3d.setProgramConstantsFromVector(Context3DProgramType.FRAGMENT, 1, Vector.<Number>([0.0, 0.0, 0.0, 1.0 / (_terrainStepsW + 1)])); // fc1.x = 0, fc1.w = nextUV
// upload geometry
_ctx3d.setVertexBufferAt(0, _vBuf, 0, Context3DVertexBufferFormat.FLOAT_3); // va0 = vertex xyz
_ctx3d.setVertexBufferAt(1, _vBuf, 3, Context3DVertexBufferFormat.FLOAT_2); // va1 = texCoord uv
_ctx3d.setVertexBufferAt(2, _vBuf, 5, Context3DVertexBufferFormat.FLOAT_3); // va2 = normal nnn
// upload texture
_ctx3d.setTextureAt(0, _diffTex); // 0 means (fs0) in the fragment shader
_ctx3d.setTextureAt(1, _bumpTex); // 0 means (fs1) in the fragment shader
// draw!
_ctx3d.drawTriangles(_iBuf, 0, _indices.length / 3);
drawSnapshot();
// backbuffer to the screen
_ctx3d.present();
// animate brush
updateBrush();
}
private function updateBrush():void {
var r:Number = 40;
var h:Number = 20;
var r0:Number = 10;
_brush = new Vector3D(r * Math.sin(-_t), h * Math.sin(.5 * _t), r * Math.cos(-_t), r0 * r0 * (2 + Math.cos(.5 * _t)));
_t += _dangle;
}
private function qualitySettings(low:*, high:*):* {
if (_HQ) {
return high;
} else {
return low;
}
}
private function drawSnapshot():void {
// render to texture if needed. should be called before _ctx3d.present();
if (_needsSnapshot) {
_needsSnapshot = false;
_ctx3d.drawToBitmapData(_snapshot.bitmapData);
_snapshot.visible = true;
_needsSnapshot = false;
// add text
var tf:TextField = new TextField();
tf.text = "This's a snapshot, press \"SPACE\" again to continue.";
tf.autoSize = TextFieldAutoSize.LEFT;
tf.textColor = 0xffffff;
_snapshot.bitmapData.draw(tf);
}
}
private function askForSnapshot():void {
if (!_snapshot) {
_snapshot = new Bitmap(new BitmapData(stage.stageWidth, stage.stageHeight, false));
addChild(_snapshot);
}
if (_snapshot.visible) {
_snapshot.visible = false;
} else {
_needsSnapshot = true;
}
}
private function keyboardHandler(e:KeyboardEvent):void {
switch (e.keyCode) {
case Keyboard.SPACE:
askForSnapshot();
break;
default:
break;
}
}
/// block
private function initInteractivity():void {
// mouse listeners
stage.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDwn);
stage.addEventListener(MouseEvent.MOUSE_UP, onMouseUp);
stage.addEventListener(MouseEvent.MOUSE_MOVE, onMouseMove);
stage.addEventListener(MouseEvent.MOUSE_WHEEL, onMouseWheel);
// touch listeners
Multitouch.inputMode = MultitouchInputMode.TOUCH_POINT;
stage.addEventListener(TouchEvent.TOUCH_BEGIN, onTouchBegin);
stage.addEventListener(TouchEvent.TOUCH_MOVE, onTouchMove);
stage.addEventListener(TouchEvent.TOUCH_END, onTouchEnd);
}
private function onMouseDwn(e:MouseEvent):void {
_mousePos2d = new Vector3D(mouseX, mouseY);
}
private function onMouseUp(e:MouseEvent):void {
_mousePos2d = null;
_rotTime = getTimer();
}
private function onMouseMove(e:MouseEvent):void {
if (!_mousePos2d) return;
_cameraRotation.x += (mouseY - _mousePos2d.y) * 0.5;
_cameraRotation.y += (mouseX - _mousePos2d.x) * 0.5;
_mousePos2d = new Vector3D(mouseX, mouseY);
}
private function onMouseWheel(e:MouseEvent):void {
var factor:Number = (e.delta > 0) ? 1.1 : 0.9;
_cameraRadius *= factor;
}
private function onTouchBegin(e:TouchEvent):void {
_mousePos2d = new Vector3D(e.stageX, e.stageY);
}
private function onTouchMove(e:TouchEvent):void {
if (!_mousePos2d) return;
_cameraRotation.x += (e.stageY - _mousePos2d.y) * 0.5;
_cameraRotation.y += (e.stageX - _mousePos2d.x) * 0.5;
_mousePos2d = new Vector3D(e.stageX, e.stageY);
}
private function onTouchEnd(e:TouchEvent):void {
_mousePos2d = null;
_rotTime = getTimer();
}
private function projMatrix(FOV:Number, aspect:Number, zNear:Number, zFar:Number):Matrix3D {
var sy:Number = 1.0 / Math.tan(FOV * Math.PI / 360.0),
sx:Number = sy / aspect;
return new Matrix3D(Vector.<Number>([
sx, 0.0, 0.0, 0.0,
0.0, sy, 0.0, 0.0,
0.0, 0.0, zFar / (zNear - zFar), -1.0,
0.0, 0.0, (zNear * zFar) / (zNear - zFar), 0.0]));
}
private function viewMatrix(rot:Vector3D, dist:Number, centerY:Number):Matrix3D {
var m:Matrix3D = new Matrix3D();
m.appendTranslation(0, -centerY, 0);
m.appendRotation(rot.z, new Vector3D(0, 0, 1));
m.appendRotation(rot.y, new Vector3D(0, 1, 0));
m.appendRotation(rot.x, new Vector3D(1, 0, 0));
m.appendTranslation(0, 0, -dist);
return m;
}
private function readModel():void {
TerrainMesh.createGeometry(_terrainW, _terrainH, _terrainStepsW, _terrainStepsH);
TerrainMesh.createTexture();
//TerrainMesh.calculateNormals();
// texture
_texture = TerrainMesh.texture;
// geometry
_verts = new Vector.<Number>();
_indices = new Vector.<uint>();
var i:uint;
for (i = 0; i < TerrainMesh.vertices.length / 3; i++) {
// xyz
_verts.push(TerrainMesh.vertices[3*i]);
_verts.push(TerrainMesh.vertices[3*i+1]);
_verts.push(TerrainMesh.vertices[3*i+2]);
// uv
_verts.push(TerrainMesh.uvs[2*i]);
_verts.push(TerrainMesh.uvs[2 * i + 1]);
// nxnynz
_verts.push(TerrainMesh.normals[3*i]);
_verts.push(TerrainMesh.normals[3*i+1]);
_verts.push(TerrainMesh.normals[3*i+2]);
}
for (i = 0; i < TerrainMesh.indices.length; i++) {
_indices.push(TerrainMesh.indices[i]);
}
}
// 2d stuff
private function initPerlinTerrain():void {
_hmap = new PerlinHeightMap(_terrainStepsW + 1, _terrainStepsH + 1);
_hmapHolder = new Bitmap(_hmap);
_hmapHolder.width = _hmapHolder.height = 50;
addChild(_hmapHolder);
/*var s:Shape = new Shape();
s.graphics.beginFill(0);
s.graphics.drawRect(0, 0, _terrainStepsW, _terrainStepsH);
s.graphics.endFill();
s.graphics.beginFill(0xffffff);
s.graphics.drawCircle(_terrainStepsW / 4, _terrainStepsH / 4, _terrainStepsW / 4);
s.graphics.drawCircle(_terrainStepsW * 3 / 4, _terrainStepsH * 3 / 4, _terrainStepsW / 8);
s.graphics.endFill();
_hmap.draw(s);*/
_bumpTex = createTexture(BitmapCalculator.resize(_hmap, 128, 128), false);
}
private function updatePerlin(e:Event = null):void {
_hmap.update();
doDisplacement();
}
private function doDisplacement():void {
// get heightmap
var pixels:Vector.<uint> = _hmap.getVector(_hmap.rect);
// update vertex data
// each vertex has 8 values: "x,y,z,u,v,nx,ny,nz"
var numVerts:uint = _verts.length / _vStride;
var i:uint = numVerts;
while (i > 0) { // the reverse "while" loop is the fastest one
// y_index = i * stride + 1
if (i < pixels.length) {
//ix = i - i % (_terrainStepsH + 1);
_verts[i * _vStride + 1] = _terrainW * .3 * BitmapCalculator.grayRGBColorToFloat(pixels[i]);
}
--i;
}
// update vertex buffer
_vBuf.uploadFromVector(_verts, 0, _verts.length / _vStride);
// convert heightmap to texture
//_bumpTex.dispose();
_bumpTex = createTexture(_hmap, false);
}
}
}
import flash.display.BitmapData;
import flash.display.Sprite;
import flash.geom.*;
class TerrainMesh {
public static var vertices:Array = [];
public static var indices:Array = [];
public static var uvs:Array = [];
public static var normals:Array = [];
public static var texture:BitmapData;
public static function createGeometry(w:Number = 100, h:Number = 100, nW:uint = 16, nH:uint = 16):void {
// vertices
var x:Number, y:Number;
var xi:uint, yi:uint;
var square:uint;
var tiles_w:uint = nW + 1;
//var numVertices:uint = (nH + 1) * (nW + 1);
//var numIndices:uint = nH * nW * 6;
vertices = new Array();
indices = new Array();
uvs = new Array();
normals = new Array();
for (yi = 0; yi <= nH; yi++) {
for (xi = 0; xi <= nW; xi++) {
x = (xi / nW - .5) * w;
y = (yi / nH - .5) * h;
vertices.push(x);
vertices.push(0);
vertices.push(y);
uvs.push(xi / nW);
uvs.push(yi / nH);
normals.push(0);
normals.push(1);
normals.push(0);
if (xi != nW && yi != nH) {
square = yi * tiles_w + xi;
indices.push(square);
indices.push(square + tiles_w);
indices.push(square + tiles_w + 1);
indices.push(square);
indices.push(square + tiles_w + 1);
indices.push(square + 1);
}
}
}
}
public static function createTexture():void {
var bmpsize:uint = 1024;
var cellsize:uint = 32;
var alpha:Number = 1;
var color:uint = 0x00ccff;
var checkerBmd:BitmapData = new BitmapData(bmpsize, bmpsize, false, 0xffffff);
var i:uint, j:uint;
var size:uint = cellsize;
var checker:Sprite = new Sprite();
checker.graphics.beginFill(color, alpha);
for (i = 0; i < checkerBmd.width / size; i++) {
for (j = 0; j < checkerBmd.height / size; j++) {
with (checker.graphics) {
drawRect((2 * i + j % 2) * size, j * size, size, size);
}
}
}
checker.graphics.endFill();
checkerBmd.draw(checker);
texture = checkerBmd;
}
public static function calculateNormals():void {
// 3 points of a triangle
var p:Vector.<Vector3D>;
// 2 adjacent edges of a triangle sharing the same origin (point 0)
var e01:Vector3D;
var e02:Vector3D;
// a normal
var n:Vector3D;
// fill the initial array of normals
var norms:Array = new Array(vertices.length, true);
var i:uint;
var j:uint;
var k:uint;
// for each triangle in mesh
for (i = 0; i < indices.length; i++) {
// get the coordinates of each 3 points of a face
p = new Vector.<Vector3D>();
for (j = 0; j < 3; j++) {
k = indices[3 * i + j]; // index of a j-th point of a triangle
p.push(new Vector3D(vertices[3 * k], vertices[3 * k + 1], vertices[3 * k + 2]));
}
// compute vectors of edges
e01 = p[1].subtract(p[0]);
e02 = p[2].subtract(p[0]);
// compute the normal and normalize (convert to unit vector)
n = e01.crossProduct(e02);
n.normalize();
// save the faceted normal
for (j = 0; j < 3; j++) {
k = indices[3 * i + j]; // index of a j-th point of a triangle
// assume, that for each 3 points of a trinagle the normal is the same
norms[3 * k] = n.x;
norms[3 * k + 1] = n.y;
norms[3 * k + 2] = n.z;
}
}
normals = norms;
}
}
class PerlinHeightMap extends BitmapData {
private var _baseX:Number;
private var _baseY:Number;
private var _octaves:uint;
private var _speed:Number;
private var _movX:Number;
private var _movY:Number;
private var _tile:uint = 5;
private var _lim:Number;
private var _offsets:Array = [0];
private var _i:uint = 0;
public function PerlinHeightMap($width:uint, $height:uint,
octaves:uint = 2, movX:Number = .1, movY:Number = 1) {
_baseX = $width / _tile;
_baseY = $height / _tile;
_octaves = octaves;
_speed = .07 * (_baseX + _baseY) / 2;
_movX = movX;
_movY = movY;
super($width, $height, false, 0);
_lim = 1000 * _tile * this.width;
}
public function update():void {
_offsets[0] = new Point(_i * _movX * _speed, _i * _movY * _speed);
this.perlinNoise(_baseX, _baseY, _octaves, 1, true, true, 7, true, _offsets);
_i = (_i > _lim) ? 0 : _i + 1;
}
}
import flash.geom.Point;
import flash.display.BlendMode;
import flash.geom.Matrix;
/**
* Flash is extremely fast in manipulating bitmaps, so let's use it for arrays
* Note: "a" and "b" operands must be the same size (width x height)
*/
class BitmapCalculator {
/*public static function colorToFloat(a:BitmapData):Number {
var multiplier
var c:BitmapData = new BitmapData(a.width, a.height, false, 0);
}*/
/**
* c = a
*/
public static function copy(a:BitmapData):BitmapData {
var c:BitmapData = new BitmapData(a.width, a.height, false, 0);
c.copyPixels(a, a.rect, new Point());
return c;
}
/**
* c = a + b
*/
public static function add(a:BitmapData, b:BitmapData):BitmapData {
var c:BitmapData = copy(a);
c.draw(b, null, null, BlendMode.ADD);
return c;
}
/**
* c = a - b
*/
public static function subtract(a:BitmapData, b:BitmapData):BitmapData {
var c:BitmapData = copy(a);
c.draw(b, null, null, BlendMode.SUBTRACT);
return c;
}
/**
* c = a * b
*/
public static function multiply(a:BitmapData, b:BitmapData):BitmapData {
var c:BitmapData = copy(a);
c.draw(b, null, null, BlendMode.MULTIPLY);
return c;
}
/**
* c = [v,v,....v]
*/
public static function dataOf(w:Number, h:uint, v:Number):BitmapData {
return new BitmapData(w, h, false, v);
}
/**
* c = [a*f, a*f, ... a*f]
*/
public static function multiplyBy(a:BitmapData, f:Number):BitmapData {
var b:BitmapData = dataOf(a.width, a.height, f);
return multiply(a, b);
}
public static function grayRGBColorToFloat(rgb:uint):Number {
return ( rgb & 0xff ) / 255;
}
public static function resize(a:BitmapData, w:uint, h:uint):BitmapData {
var c:BitmapData = new BitmapData(w, h, false);
var mx:Matrix = new Matrix();
mx.scale(w / a.width, h / a.height);
c.draw(a);
return c;
}
}