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Romhacking => ROM Hacking Discussion => Topic started by: ghostdwl on July 16, 2018, 08:52:35 am

Title: [PSX] How to find a graphic in memory?
Post by: ghostdwl on July 16, 2018, 08:52:35 am
I'm looking for a graph in memory during gameplay, I know the location of this graph out of memory, is there any way I can find the function that writes the graph or its location in memory?
I know how to use the debugger and program in reverse language of the psx, then skip the initial explanations.
Title: Re: [PSX] How to find a graphic in memory?
Post by: tvtoon on July 16, 2018, 02:17:01 pm
Well, seems you don't know about CDROM commands, that is probably what you are looking for... check nocash etc documentation for how it is used.

There is a specific set of them for reading sectors and blocks.
Title: Re: [PSX] How to find a graphic in memory?
Post by: Valendian on July 16, 2018, 02:22:33 pm
Texture and sprite data must be DMA transferred to VRAM. Polygons must be drawn. The pSX emulator (https://www.romhacking.net/utilities/311/) has a debug menu which allows you to debug gpu commands. You can capture a number of frames and it will allow you to step through the rendering of each frame one polygon at a time. For each polygon you can see which function issued the draw command.