Bitmap rotation jitter around pivot

Posted by Manderin87 on Game Development See other posts from Game Development or by Manderin87
Published on 2012-11-15T19:09:10Z Indexed on 2012/11/16 5:14 UTC
Read the original article Hit count: 211

Filed under:
|
|
|

I am working on a asteriods clone and I have the ship graphic loaded as a 96x96 bitmap. When the player rotates the ship I rotate the bitmap by degree (float).

rotation function:

if(m_Matrix == null) {
  m_Matrix = new Matrix();
} else {
  m_Matrix.reset();
}

m_Matrix.setRotate(degree, m_BaseImage.getWidth() / 2, 
                           m_BaseImage.getHeight() / 2);

m_RotatedImage = Bitmap.createBitmap(m_BaseImage, 0, 0, m_BaseImage.getWidth(),
                                                        m_BaseImage.getHeight(),
                                                        m_Matrix, true);   

draw function:

m_Paint.setAntiAlias(true);
m_Paint.setFilterBitmap(true);
m_Paint.setDither(true);

canvas.drawBitmap(m_RotatedImage, (int) posX - m_RotatedImage.getWidth() / 2, 
                                  (int) posY - m_RotatedImage.getHeight() / 2, m_Paint);

When the bitmap is drawn, the bitmap jitters slightly around the pivot.

Can anyone fix or tell me why the bitmap is jittering around the pivot? It needs to be smooth.

© Game Development or respective owner

Related posts about java

Related posts about android