Interesting project. I think my main problem is how I developed my display driver. First and foremost it was a text driver and nothing more, it wasn't until I leveraged the power of Lua I saw the potential of a graphical mode. Working with an RP2040 more memory was needed to run user code and graphical buffers used a lot of RAM so I started with monochrome then added the more colours and reduced the resolution so it would all fit into the 16K RAM. My driver is based roughly on CGA that only ever had 16 colours the fact I could get a 256 colour mode was just gravy.Hello,
I spent (too much) time searching for a "silver bullet" in terms of video modes that should be available with 64K (Pico), 128K (Pico2) or even more than 256K like 448K (Pimoroni Pico Plus 2 with 8M of PSRAM which could handle Lua code).
I'm still convinced that 160x200 or 320x400 modes should be implemented in addition to 320x100.
200 make 25 lines of 8 pixels text, 100 just 12.5 which seems weird, and most of the 80's computers I know had video circuitry that could handle horizontal changes but not vertical ones, even if horizontal timings are rather tight.
Another big change I would do is to use multiplane capabilities of scanvideo library to handle framebuffer, sprites & text console as 3 layers.
That is what I try to do in my VGA library project https://github.com/CHiPs44/hagl_pico_vg ... e/textmode.
Keep up with your ideas anyway!
The VRAM library is written with the 16bit addressing in mind and it seems that expanding the video driver beyond it's original design has brought up that the addresses need more bits to work and really a need to rework that interface.
I didn't look into your code but the idea of layers is interesting I have something like that with the overlay and graphics but the process is too slow as my text mode translates bitmaps to text on the fly so getting more that small sprites over text takes too long.
I think this is just the limits of the PT video driver and it's design ideas, and really that's okay it's trying to be an 80's like computer so limited graphics is okay.
The Pico Plus 2 now that's a board I need to play with... all that RAM would be amazing to have, something to look at once I get the bugs out. likely that would be it's own project with a very different goal.
Statistics: Posted by DarkElvenAngel — Sun Feb 02, 2025 3:17 am