In the GBC version of Marble Madness, the window is used to display the score at the bottom of the frame during gameplay. This is accomplished by setting WX to 7 on scanline 136. The window is hidden above that scanline with WX set to 167. WY is set to 0 throughout the frame, but the text to be displayed appears in memory at what should be the top of the window. Consequentially, if I force WY to 136 in my emulator, the text properly appears at the bottom of the frame. Leaving WY as 0 draws the wrong strip of tiles.
I assume that either WY is not getting set correctly or that the text was injected into the wrong location in VRAM. Or, perhaps the PPU is reading the wrong piece of VRAM that just happens to line up when I force WY to 136. Any suggestions? Thanks.
I assume that either WY is not getting set correctly or that the text was injected into the wrong location in VRAM. Or, perhaps the PPU is reading the wrong piece of VRAM that just happens to line up when I force WY to 136. Any suggestions? Thanks.