Gunnar von Boehn
(Apollo Team Member)
Posts 6254
21 Mar 2016 19:38
| Here is an example how to get Sprite Routines,
like for example used by SDL, super fast.
Super fast means here ~ 100 times faster
than Bob routines on Classic Amiga. :-)
In other words Sprite copy with 400 MB/sec
These SDL Sprite routines use Chunky Pixel
But need to support MASKING operation e.g. transparent pixels.
We show here a simple Code example which does this very efficient.
Lets say SPRITE-SRC-PRT in A0
Lets say SCREEN-PRT in A1
Lets say D0=$0
Lets say D7 = 64bit words to copy per row
For optimal speed Screen-PTR should be aligned to LONG,
SRC-POINTER does not need to be aligned as APOLLO
can correct misaligned reads for free.
LOOPX:
MOVE.Q (A0)+,D1 ; load 8 pixel (each 256 color)
PCMPeq.B D0,D1,D2 ; check for background pixel, create mask
BSEL D2,(A1),D1,D3 ; load background and combine bytes
MOVE.Q D3,(A1)+
DBF D7,LOOPX
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