NBG3, NBG0 do not seem to be accessible

johannes-fetz / joengine

Jo Engine is an open source 2D and 3D game engine for the Sega Saturn written in C under MIT license

http://jo-engine.org/

MIT License

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NBG3, NBG0 do not seem to be accessible #59

Closed retrohead closed 3 years ago

retrohead commented 3 years ago

I have tried many things to access NBG0 and NBG3, using the line scroll demo I changed it to jo_vdp2_set_nbg3_8bits_image and changed the make file to disable printf. This worked but when I enable other screens, I am getting corruption.

I would like to simply change the colour of another background other than NBG1 for now, is there an alternative function I can use?

johannes-fetz commented 3 years ago

Hi, I need a sample that show the problem.

retrohead commented 3 years ago

demo - line scroll.zip

This shows the corruption to NBG1 when loading into NBG3.

Mednafen will load NBG3 but Yabause and Hardware both do the same with a completely black NBG3 and corruption on the top layer.

Disabling the other scroll screens will make it work.

fafling commented 3 years ago

If NBG1 is set to 16 bpp like in this demo, NBG3 can't be displayed. See VDP2 manual p. 61.

johannes-fetz commented 3 years ago

Yes:

When NBG0 is set as 2048 or 32768 colors, NBG2 can not longer be displayed.
When NBG0 is set at 16,770,000 colors, NBG1 to NBG3 can not longer be displayed.
When NBG1 is set at 2048 or 32768 colors, NBG3 can longer be displayed.