AndEngine中移动背景（上下移动、斜着移动）

在AndEngine中移动背景以使得道具/人物在屏幕地图上移动，类似赛车、滑雪等游戏看着像人物在移动，其实动的是背景，所以移动背景就可以模拟出在屏幕上的移动

在AndEngineExamples中有一个移动背景的例子：AutoParallaxBackgroundExample，在该类中使用了AutoParallaxBackground作为自循环绘画的背景在使用

但该例子中只有横向背景的移动，竖向方向的移动没有做，看AndEngine中的代码也没有关于竖向方向的计算、绘图，因此扩充了ParallaxBackground中的ParallaxEntity实现以便于移动背景的横向、竖向、斜向的移动，代码见下面：替换掉原版的后重新生成andengine.jar，然后放到自己的工程下面即可

public static class ParallaxEntity {// ===========================================================// Constants// ===========================================================// ===========================================================// Fields// ===========================================================float mParallaxFactorX;float mParallaxFactorY;final IAreaShape mAreaShape;// ===========================================================// Constructors// ===========================================================public ParallaxEntity(final float pParallaxFactorX, final IAreaShape pAreaShape) {this.mParallaxFactorX = pParallaxFactorX;this.mParallaxFactorY = 0;this.mAreaShape = pAreaShape;}public ParallaxEntity(final float pParallaxFactorX, final float pParallaxFactorY, final IAreaShape pAreaShape) {this.mParallaxFactorX = pParallaxFactorX;this.mParallaxFactorY = pParallaxFactorY;this.mAreaShape = pAreaShape;}// ===========================================================// Getter & Setter// ===========================================================// ===========================================================// Methods for/from SuperClass/Interfaces// ===========================================================// ===========================================================// Methods// ===========================================================public void onDraw(final GLState pGLState, final Camera pCamera, final float pParallaxValue) {pGLState.pushModelViewGLMatrix();{final float cameraWidth = mParallaxFactorX != 0 ? pCamera.getWidth() : 0;final float cameraHeight = mParallaxFactorY != 0 ? pCamera.getHeight() : 0;final float shapeWidthScaled = this.mAreaShape.getWidthScaled();final float shapeHeightScaled = this.mAreaShape.getHeightScaled();float baseOffsetX = mParallaxFactorX != 0 ? (pParallaxValue * this.mParallaxFactorX) % shapeWidthScaled : 0;float baseOffsetY = mParallaxFactorY != 0 ? (pParallaxValue * this.mParallaxFactorY) % shapeHeightScaled : 0;//while(baseOffsetX > 0) {baseOffsetX -= shapeWidthScaled;}while(baseOffsetY > 0) {baseOffsetY -= shapeHeightScaled;}pGLState.translateModelViewGLMatrixf(baseOffsetX, baseOffsetY, 0);//float currentMaxX = baseOffsetX;float currentMaxY = baseOffsetY;booleanbX = mParallaxFactorX != 0 ? true : false;booleanbY = mParallaxFactorY != 0 ? true : false;do {this.mAreaShape.onDraw(pGLState, pCamera);if (bX && bY){pGLState.translateModelViewGLMatrixf(shapeWidthScaled, shapeHeightScaled, 0);currentMaxX += shapeWidthScaled;currentMaxY += shapeHeightScaled;}else if (bX && !bY){pGLState.translateModelViewGLMatrixf(shapeWidthScaled, 0, 0);currentMaxX += shapeWidthScaled;}else if (!bX && bY){pGLState.translateModelViewGLMatrixf(0, shapeHeightScaled, 0);currentMaxY += shapeHeightScaled;}bX = currentMaxX < cameraWidth ? true : false;bY = currentMaxY < cameraHeight ? true : false;} while(bX || bY);}pGLState.popModelViewGLMatrix();}// ===========================================================// Inner and Anonymous Classes// ===========================================================}

//位于ParallaxBackground类中