I’ve mentioned before that SZLib presents challenges:
The downside to completely ignoring the capabilities of the DS hardware and doing all of the graphics work with just the CPU and a framebuffer is that it is insanely expensive.
However, its bare-bones approach - it just needs a framebuffer and a way to read a joystick, pretty much - made getting it working on the Dreamcast fairly trivial. Getting it working on other platforms should be simple too, but when choosing a new platform for the library I eliminated everything but the Dreamcast as a potential target.
I was too hasty when I crossed the PSP off that list. The handheld does offer the ability to write directly to the framebuffer. It took about an hour or so to get to this point:
By far the hardest part was getting MikMod set up to play sound effects, which took a couple of hours on its own.
There’s a little bit of work to do. The PSP has a physical screen size of 480x272, but for some reason it seems that the frame buffer is 512 pixels wide. The disconnect between the physical and logical sizes means everything is slightly off-center. Also, the “home” button isn’t wired up yet. Overall, though, the game works just as well on the PSP as it doesn on the Dreamcast and NDS.
Excitingly, because they’re based on the same libraries, HankyAlien also now runs on the PSP.