Nemesis' Sprite Masking and Overflow Test ROM is a test ROM used to verify the emulation of several Sega Mega Drive VDP quirks, including sprite limits.
The following tests are performed by the Sprite Masking and Overflow Test ROM.
- H32 == 256x224 display mode
- H40 == 320x224 display mode.
- Sprite mask: A sprite with X=0.
- Max Sprites Per Line: 16 in H32, 20 in H40.
- Max Sprite Dots - Basic: Up to 256 sprite dots in H32; 320 in H40.
- Max Sprite Dots - Complex: Same as previous, except it verifies that sprites are cut off in the middle.
- Sprite Mask: Verifies that lower-priority sprites are masked if a sprite mask exists and is not the first sprite on the line.
- Sprite Mask S1: Verifies that lower-priority sprites are *not* masked if a sprite mask exists and is the first sprite on the line.
- Mask S1 On Dot Overflow: Verifies that sprite masks at the beginning of the line are ineffective if sprite dot overflow occurs on the previous line.
- Mask S1,X=1 S2,X=0: Verifies that the non-existent sprite masking "Mode 2" is not implemented.
- Mask S1,X=40 S2,X=0: Same as previous.
- Max Sprites Per Frame: 64 in H32, 80 in H40.
For tests with two results, the left result indicates that the minimum boundary is respected, and the right result indicates that the maximum boundary is respected.
Test #6 is conditional on test #5 passing. If test #5 passes, then test #6 passing is an error (indicated by a red line underneath "PASS").
Gens/GS r7+ (git: vdp-to-cpp/86948622) (also applies to Gens/GS II)
TODO: Add test results from other emulators.