Rotating bitmap in main game loop without overloading GC in Android

Question

What is the correct way to rotate bitmap every frame in main game loop? What I have tried:

I created rotated bitmap every frame:

Bitmap image, tmp;
Matrix m;
...
public void mainGameLoop(Canvas c){
    m.reset();
    m.postRotate(angle);
    tmp = Bitmap.createBitmap(image, 0, 0, width, height, m, true);
    c.drawBitmap(tmp, 50, 50, null);
}

However, because Bitmap.createBitmap creates bitmap every frame Garbage Collector works so madly, it causes low FPS.

I have tried saving bitmap in array at all angles, and just taking bitmap which I want to. However, this needs a lot of RAM and app just couldn't launch at high screen resolutions.

If you have any ideas, please comment below.

Why you use createBitmap every frame?! Create it ones and use rotate method in canvas — Piotr Golinski, Apr 25 '15 at 14:25
refer here http://stackoverflow.com/questions/4166917/android-how-to-rotate-a-bitmap-on-a-center-point .. you can apply the rotaion while drawing — Dinesh Kannan, Apr 25 '15 at 14:31

score 0 · Accepted Answer · answered Apr 25 '15 at 14:33

Some think like this:

Bitmap image;
Matrix m;
.
.
.
public YourClass(){
    m = new Matrix();
    image = Bitmap.createBitmap(image, 0, 0, width, height,);
}
.
.
.
public void mainGameLoop(Canvas c){
    m.setRotate(angle, imageCenterX, imageCenterY);
    yourCanvas.drawBitmap(image, m, null);
}

Rotating bitmap in main game loop without overloading GC in Android

1 Answers1