NO IMAGE

在壇裡看到過有朋友貼過不規則物體碰撞檢測的類,這裡,我再貼個一位牛老外寫的一個類,經自己測試,用一個1500*1500的向量圖和一個10*10的不短移動的小球進行碰狀檢測,CPU佔用僅4%左右,超級高效!!!
這裡是程式碼:
Actionscript:

CODE:

package ws.tink.display
{
 
import flash.display.BitmapData;
import flash.display.BlendMode;
import flash.display.DisplayObject;
import flash.display.Sprite;
 
import flash.geom.ColorTransform;
import flash.geom.Matrix;
import flash.geom.Point;
import flash.geom.Rectangle;
 
public class HitTest
{
 
public static function complexHitTestObject( target1:DisplayObject, target2:DisplayObject, accurracy:Number = 1 ):Boolean
{
return complexIntersectionRectangle( target1, target2, accurracy ).width != 0;
}
 
public static function intersectionRectangle( target1:DisplayObject, target2:DisplayObject ):Rectangle
{
// If either of the items don't have a reference to stage, then they are not in a display list
// or if a simple hitTestObject is false, they cannot be intersecting.
if( !target1.root || !target2.root || !target1.hitTestObject( target2 ) ) return new Rectangle();
 
// Get the bounds of each DisplayObject.
var bounds1:Rectangle = target1.getBounds( target1.root );
var bounds2:Rectangle = target2.getBounds( target2.root );
 
// Determine test area boundaries.
var intersection:Rectangle = new Rectangle();
intersection.x = Math.max( bounds1.x, bounds2.x );
intersection.y = Math.max( bounds1.y, bounds2.y );
intersection.width = Math.min( ( bounds1.x bounds1.width ) - intersection.x, ( bounds2.x bounds2.width ) - intersection.x );
intersection.height = Math.min( ( bounds1.y bounds1.height ) - intersection.y, ( bounds2.y bounds2.height ) - intersection.y );
 
return intersection;
}
 
public static function complexIntersectionRectangle( target1:DisplayObject, target2:DisplayObject, accurracy:Number = 1 ):Rectangle
{
if( accurracy < = 0 ) throw new Error( "ArgumentError: Error #5001: Invalid value for accurracy", 5001 );
 
// If a simple hitTestObject is false, they cannot be intersecting.
if( !target1.hitTestObject( target2 ) ) return new Rectangle();
 
var hitRectangle:Rectangle = intersectionRectangle( target1, target2 );
// If their boundaries are no interesecting, they cannot be intersecting.
if( hitRectangle.width * accurracy < 1 || hitRectangle.height * accurracy < 1 ) return new Rectangle();
 
var bitmapData:BitmapData = new BitmapData( hitRectangle.width * accurracy, hitRectangle.height * accurracy, false, 0x000000 );
 
// Draw the first target.
bitmapData.draw( target1, HitTest.getDrawMatrix( target1, hitRectangle, accurracy ), new ColorTransform( 1, 1, 1, 1, 255, -255, -255, 255 ) );
// Overlay the second target.
bitmapData.draw( target2, HitTest.getDrawMatrix( target2, hitRectangle, accurracy ), new ColorTransform( 1, 1, 1, 1, 255, 255, 255, 255 ), BlendMode.DIFFERENCE );
 
// Find the intersection.
var intersection:Rectangle = bitmapData.getColorBoundsRect( 0xFFFFFFFF,0xFF00FFFF );
 
bitmapData.dispose();
 
// Alter width and positions to compensate for accurracy
if( accurracy != 1 )
{
intersection.x /= accurracy;
intersection.y /= accurracy;
intersection.width /= accurracy;
intersection.height /= accurracy;
}
 
intersection.x = hitRectangle.x;
intersection.y = hitRectangle.y;
 
return intersection;
}
 
 
protected static function getDrawMatrix( target:DisplayObject, hitRectangle:Rectangle, accurracy:Number ):Matrix
{
var localToGlobal:Point;;
var matrix:Matrix;
 
var rootConcatenatedMatrix:Matrix = target.root.transform.concatenatedMatrix;
 
localToGlobal = target.localToGlobal( new Point( ) );
matrix = target.transform.concatenatedMatrix;
matrix.tx = localToGlobal.x - hitRectangle.x;
matrix.ty = localToGlobal.y - hitRectangle.y;
 
matrix.a = matrix.a / rootConcatenatedMatrix.a;
matrix.d = matrix.d / rootConcatenatedMatrix.d;
if( accurracy != 1 ) matrix.scale( accurracy, accurracy );
 
return matrix;
}
 
}
 
}

封裝了3個靜態方法,直接用傳參呼叫即可!

演算法值得學習。
這裡是原文地址:http://www.tink.ws/blog/as-30-hittest