android 3D旋转效果实现

一说到3D，可能第一反应就是使用OpenGL ES。。。。但是，实现这么个小功能，要动用这玩意，莫名的恐惧啊！！！！至今也没弄明白这个怎么玩。。。

好吧，幸亏还有个Camera类可以帮助我们，据说底层实现实现也是使用的是OpenGL ES 

注意：使用的是android.graphics.Camera  

话不多说了，直接上代码：

public class _3DAnimation extends Animation {
    private  float mFromDegrees;
    private  float mToDegrees;
    private  float mCenterX;
    private  float mCenterY;
    private Camera mCamera;
    public  _3DAnimation(float fromDegress,float toDegress){
        this.mFromDegrees=fromDegress;
        this.mToDegrees=toDegress;

    }
    @Override
    public void initialize(int width, int height, int parentWidth, int parentHeight) {
        super.initialize(width, height, parentWidth, parentHeight);
        this.mCenterX=width/2;
        this.mCenterY=height/2;
        mCamera=new Camera();
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        super.applyTransformation(interpolatedTime, t);
        final float fromDegrees = mFromDegrees;
        float degrees = fromDegrees + (mToDegrees - mFromDegrees) * interpolatedTime;
        final Matrix matrix = t.getMatrix();
        //interpolatedTime 0~1变化
        mCamera.save();
        mCamera.rotateY(degrees);
        mCamera.getMatrix(matrix);
        mCamera.restore();
        matrix.preTranslate(-mCenterX, -mCenterY);//相机位于（0,0），移动图片，相机位于图片中心
        matrix.postTranslate(mCenterX, mCenterY);
    }
}