I created Bitmap Graphics Library for RP6502

[vruumllc]

Here is a simple bitmap graphics library and demo program that I created for the RP6502:

https://github.com/vruumllc/RP6502-Bitmap_Graphics

It makes creating simple background graphics easy for all the bitmap modes (mode3) the RP6502 supports.
Updated for new CC65 compiler with rp6502 support.
Enjoy!

[rumbledethumps]

If you want to eek out that last bit of performance before jumping into assembly, check this: https://github.com/ilmenit/CC65-Advanced-Optimizations

[rumbledethumps]

Try this:

    if (bpp == 16) {
        RIA.addr0 = (canvas_width() * y + x) * 2;
        RIA.step0 = 1;
        RIA.rw0 = color;
        RIA.rw0 = color >> 8; // You forgot to shift

[vruumllc]

Excellent! That did the trick.
It looks like the bugs are in your mode3 demo code, too, which I just copied.

[rumbledethumps]

Probably lots of other things in that file that turn into bugs after copypasta.

// This is not good code to learn from,
// it's a functional test for developing mode3.

The documentation is the only source of truth.

[vruumllc]

Indeed. Unfortunately, I'm a (lazy?) learn-by-example kind of guy.

BTW, I saw the >> 8 fix on github, but I still think you need to multiply x1*2 as well:
RIA.addr0 = 480 * y + x1; // I think X1 should be multiplied by 2 here

Thanks so much for your patience and help! I am having so much fun with this project. I'm working on some optimizations now.

[vruumllc]

I have replaced the bitmap_graphics.zip file, above, with a corrected version.

[vruumllc]

I have added my Bitmap Graphics library to my GitHub repositories, and have modified the initial post to point to it.

I have also added a version of the library for the LLVM-MOS C compiler.