Gens/GS r7+ - 模擬器

http://forums.sonicretro.org/index.php?showtopic=18380&st=45&p=401134&
#entry401134

Since I'm essentially doing a full rewrite of the VDP code by porting it to
C++, I decided that I might as well improve some of the code related to
sprite masking and overflow. Nemesis wrote a test ROM for this a while back
(see http://gendev.spritesmind.net/forum/viewto...php?p=8364#8364), and that
test ROM is what I used as a reference point. Note that the sprite system
varies slightly depending on the horizontal resolution, so each of these
images consists of an H32 mode screenshot (left; 256x224) and an H40 mode
screenshot (right; 320x224).


Gens/GS r7+ now passes "Max Sprites Per Line" (16 in H32; 20 in H40) and "Max
Sprite Dots - Complex". Still not supported is the S1 sprite mask, though it
seems that S1 is masked on dot overflow for some reason. EDIT: This test is
invalid due to S1 masking failure, as indicated by the red line.

Note: For old times' sake, if you disable the "Sprite Limit" option in the
Graphics menu, then tests 1, 2, and 3 will all fail. The most obvious
side-effect of doing this can be seen on Sonic 1's title screen. The original
Gens only passed test #2 out of those three when "Sprite Limit" was enabled.
Also, original Gens did not pass test #9 in H32 mode, since it assumed a
maximum of 80 sprites per frame regardless of the horizontal resolution. This
was fixed in Gens/GS r7.


I implemented S1 sprite masking. Gens/GS now passes all tests.

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