mamedev
suprloco.cpp: accuracy overhaul based on recent pcb tracing and schematic generation
Corrected palette PROM hookups for tilemap and sprites; most colors should now be correct, especially in super locomotive mode, although some work remains to get this 100% accurate. Removed a palette hack to generate 'fake' colors which had worked around incorrect mapping of the palette PROM. System1-style main cpu clock divider is now emulated. Corrected the sprite-bg priority with transparent pens so the trestle bridge now correctly shows the train through the gaps. Large documentation updates and memory map clarification and correct mirrors based on schematics from PCB tracing. Fixed an old regression with flip screen and sprite offsets, which should be correct now. Added sound filtering. [Lord Nightmare, holub, Raki(Sehyeon Kim)]
At the suggestion of hap and smf I'm making some additional changes, notably to reduce the number of ridiculously long lines in the file to a managable level, and optimizing the way some of the tilemap pen flags get initialized
Revisiting this, @Lord-Nightmare did you have a chance to try updating this to use an off-screen bitmap and then mix into the screen bitmap?
