BG3_CR = BG_BMP16_512x512;

  s16 s = SIN[0] >> 4;
  s16 c = COS[0] >> 4;
  BG3_XDX = ( c * (320-8))>>8;
  BG3_XDY = (-s * (320-8))>>8;
  BG3_YDX = ( s * (512-224+8))>>8;
  BG3_YDY = ( c * (512-224+8))>>8;