Raycaster demo (written in c and assembly)
This version is a big improvement in performance: it now runs at 10+ fps!
I am quite happy with the speed. The demo plays quite nicely now.
See below description of version 1.3.0 for details.
This is a raycaster demo written in c and assembly for the Commander x16. I've been trying out the x16 and thought it would be a cool idea to start working on a raycaster.
Ultimately it would be great if "Wolfenstein 3D" can somehow be ported to the x16. That would be a BIG challenge though!
This is how it looks now:
Speed improvements in 1.3.0:
Now running at 10+ fps!
- Using zero page addresses for pretty much all my variables
- Using fast multipliers that use "square" tables: https://codebase64.org/doku.php?id=base:seriously_fast_multiplication
- Inlined the fast multipliers, so less copying of values, no jsr and rts
- Re-using the somewhat "static" parts of the multiplications, so it won't be re-loaded/calculate each ray (this was harder than it sounds, quite of bit of refactoring done)
- Cosine and Sine fractions are player-related, and even though they are negated sometimes, they (that is their squares) could be reused for (almost) each ray
- The (square of the) fraction of the tile the player is standing in -to be used for calculating the initial x/y interception for each ray- could be reused
- Cleaned up the main loop and several other parts
- Replaced the 16-bit slow divider with a 512-entry table: distance2height (major improvement!!)
New in this version 1.2.0:
- draw functions have been ported to assembly. Much faster!
- dda casting functions have been ported to assembly. Much faster!
- drawing textures!
- automatic generation of routine to draw ceiling and floor (only 4 cycles per plain pixel)
- automatic generation of around 512 routines for drawing textures (only 8 cycles per textures pixel)
- using joystick controls (you can use arrow keys and alt to control, you can hold down keys)
- a few textures from Wolfenstein 3D (shareware version) have been added (loaded at startup)
- changed the map to look like the first level in Wolfenstein 3D
- added a border around the render area, just like Wolfenstein 3D
Unpack the zip. Make sure you have the .BIN files in the same folder as the source files.
To compile: (this assumes cc65 is installed)
cl65 -t cx16 -o RAY.PRG ray.c ray_asm.asm -O3
x16emu.exe -prg RAY.PRG -run
up - move forwards
down - move backwards
left - turn left
right - turn right
alt-left - strafe left
alt-right - strafe right
p - turn on log screen
o - turn off log screen
t - turn on test ray
l - rotate test ray left
j - rotate test ray right
Known issues (1.2.0)
- Sometimes there is a corner of a wall not drawn correctly
- Since there is no real V-sync you get "shearing" in the screen (requires double buffering)
- Lots of speed improvements
- Lots of cleanup of code (its messy now)
- Add a time-per-frame indicator (using a vsync interrupt counter)
- Mooaarr wall-textures!
- Double buffer to prevent shearing
- Show a map on the screen
- Bigger map (limit is now 16x16)
- Opening doors
- Add (scaled) "sprites"
- Lamps (scaled) hanging from ceiling
- Stats in lower part, gun visible
- AI, enemies