Thanks for the explanation! About rtcom it still amazes me to think the 3ds circle pad was possible to use in DS mode, regarding the vid you posted a while ago.
I've been playing around with the darkned filter in twpatcher and it's pretty nice. It makes me wonder if similar filters like a black and white and maybe a blue filter are possible or if that's more like a shader and requires more processing?
It's actually @Gericom who discovered rtcom, both on the ARM7 and on the ARM11. I just drafted the protocoll, and slightly modified Nintendo's code so it works better.
As for the filters, only 1D matrix-based filters work. Blur, sharpen, edge detect, etc. Although it's possible to assign different matrixes to pixels in a repeating pattern, I see no fancy use other than for upscaling purposes (that's actually how upscaling works).
As for shaders, the PICA200 has a fixed pixel shading stage, meaning you can't reprogram it, and thus no fancy filters. This also means no color correction (4x4 matrixes). The LUT is however reprogrammable, and that's actually how CTR_Redshift works!
The only feasible thing would be using the CPU to modify the framebuffer, but considering how little CPU time I have available, it wouldn't be possible without performance degradation in rendering.
Last edited by Sono,
, Reason: corrected wording