A3D Decal类

Decal，一种用于表现在普通材质之上的特殊纹理。一般用于表现场景中的血迹，弹痕，标记等。

而且这种纹理不会像普通纹理一样出现深度冲突。

普通纹理和Decal对比

当我们拉远镜头时，就变成了这样：

package {
    import alternativa.engine3d.controllers.SimpleObjectController;
    import alternativa.engine3d.core.Camera3D;
    import alternativa.engine3d.core.Object3D;
    import alternativa.engine3d.core.Resource;
    import alternativa.engine3d.core.View;
    import alternativa.engine3d.materials.TextureMaterial;
    import alternativa.engine3d.objects.Decal;
    import alternativa.engine3d.primitives.Box;
    import alternativa.engine3d.resources.BitmapTextureResource;
    import flash.display.Sprite;
    import flash.display.Stage3D;
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    import flash.events.Event;
 
    /**
     * ...
     * @author redefy
     */
    public class TestDecal extends Sprite {
        [Embed(source="resources/Smoke Kick.png")]
        private static const Smoke:Class;
        [Embed(source="resources/crumple.jpg")]
        private static const Crumple:Class;
        private var rootContainer:Object3D = new Object3D();
 
        private var camera:Camera3D;
        private var stage3D:Stage3D;
        private var simpleController:SimpleObjectController;
 
        private var boxOut:Box;
        private var boxIn:Box;
 
        private var decalOut:Decal;
        private var decalIn:Decal;
 
        public function TestDecal(){
            stage.align = StageAlign.TOP_LEFT;
            stage.scaleMode = StageScaleMode.NO_SCALE;
 
            camera = new Camera3D(0.1, 200000);
            camera.view = new View(800, 500);
            camera.rotationX = -90 * Math.PI / 180;
            camera.z = 100
            camera.y = -1200;
            addChild(camera.diagram);
            addChild(camera.view);
 
            boxOut = new Box(400, 400, 400);
            var boxOutMaterial:TextureMaterial = new TextureMaterial(new BitmapTextureResource(new Crumple().bitmapData));
            boxOut.addSurface(boxOutMaterial, 12, 2);
            boxOut.x = 400;
            rootContainer.addChild(boxOut);
 
            boxIn = new Box(200, 200, 200);
            var boxInMaterial:TextureMaterial = new TextureMaterial(new BitmapTextureResource(new Smoke().bitmapData));
            boxInMaterial.useDiffuseAlphaChannel = true;
            boxIn.addSurface(boxInMaterial, 12, 2);
            boxIn.x = 400;
            boxIn.y = -101;
            rootContainer.addChild(boxIn);
 
            decalIn = new Decal(); 
            decalIn.geometry = boxIn.geometry;
            decalIn.addSurface(boxInMaterial, 12, 2);
            decalIn.x = -400;
            decalIn.y = -101;
            rootContainer.addChild(decalIn);
 
            decalOut = new Decal(); 
            decalOut.geometry = boxOut.geometry;
            decalOut.addSurface(boxOutMaterial, 12, 2);
            decalOut.x = -400;
            rootContainer.addChild(decalOut);
 
            rootContainer.addChild(camera);
 
            simpleController = new SimpleObjectController(stage, camera, 400);
 
            stage3D = stage.stage3Ds[0];
            stage3D.addEventListener(Event.CONTEXT3D_CREATE, onContextCreate);
            stage3D.requestContext3D();
        }
 
        private function onContextCreate(e:Event):void {
            for each (var resource:Resource in rootContainer.getResources(true)){
                resource.upload(stage3D.context3D);
            }
            stage.addEventListener(Event.ENTER_FRAME, onEnterFrame);
        }
 
        private function onEnterFrame(e:Event):void {
            camera.render(stage3D);
            simpleController.update();
        }
    }
}