Ballz 3D RTX

This project upgrades the visuals of Ballz 3D with the power of raytracing.

Setup

Acquire the Ballz3D rom dump with md5 sum 339a8c9a96fcdedb2922b04bcc34f0d2. (Other versions of the game not yet tested.)

The blastem directory contains a copy of the source code of https://www.retrodev.com/blastem/ , modified (eventually) to support raytracing (?).

Could either: (1) in-engine (have background layers handy) (2)

How do frames get to the screen?

Frames copied to render_sdl.c by render_framebuffer_updated (or copied to internal buffer?)

One place to grab memory would be in advance_output_line (vdp.c) Another would be in render_framebuffer_updated (render_sdl.c)

Where to sneak in extra ballz-y data? Could just allocate thicker framebuffer buffers and copy data in there(!)

Where is main memory? m68k_context appears to perhaps be the thing (nope!) genesis_context.work_ram (genesis.h)

Okay, so can we grab work ram when vdp advances line? (prolly! threads? who knows!)

Current things:

flipped depth test and y axis because that gets closer to what we expect; might be more elegant to do ... anything else (also: need to test with demo camera pivot)
scale factor for center offset seems to be 1.0 but maybe I'm doing something wrong (thought: what if it's in post-transform space?)
character rotations are weird; maybe the local facing directions are in camera space?
what is the canvas size?
what is the focal length actually doing?