Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
04856 Graphics Minor Always May 23, 2012, 00:47 Dec 3, 2018, 08:56
Tester M.A.S.H. View Status Public Platform MAME (Self-compiled)
Assigned To Resolution Open OS Windows XP
Status [?] Confirmed Driver playch10.cpp
Version 0.146 Fixed in Version Build Normal
Summary 04856: pc_sjetm: Corrupt start screen
Description Since MAME 0.108u1 (!) there is one corrupt screen right after insert coin in Solar Jetman.
Steps To Reproduce
Additional Information
Regression Version 0.108u1
Affected Sets / Systems pc_sjetm
Attached Files
gif file icon pc_sjetm.gif (16,450 bytes) May 23, 2012, 00:47 Uploaded by M.A.S.H.
related to 06130Confirmed pc_sjetm: Graphics issue on Solar Jetman (Play Choice 10) 
User avatar
Senior Tester
Dec 3, 2018, 08:56
MAME 0.204

src\devices\video\ppu2c0x.cpp line 787:

// The sprite collision acts funny on the last pixel of a scanline.
// The various scanline latches update while the last few pixels
// are being drawn. Since we don't do cycle-by-cycle PPU emulation,
// we fudge it a bit here so that sprite 0 collisions are detected
// when, e.g., sprite x is 254, sprite y is 29 and we're rendering
// at the end of scanline 28.
// Battletoads needs this level of precision to be playable.
if ((sprite_index == 0) && (sprite_xpos == 254))
/* set the "sprite 0 hit" flag if appropriate */
if (line_priority[sprite_xpos] & 0x02)

This extra collision hack for the NES game Battletoads (MESS) breaks Solar Jetman.
It was added in MAME 0.108u1 == Regression Version