Sylvain Lefebvre Profile picture
Researcher-maker-hacker focusing on Computer Graphics with a #retro, #fpga gaming twist. Enjoys #3dprinting and #electronics. Created @iceslapp and #Silice.
Dec 23, 2022 19 tweets 10 min read
a5k: Another World on a chip! This is a hardware remake of the Another World VM and renderer (no traditional CPU), that fits on a UP5K #fpga (5K LUTs, 128KB SPRAM).

Thread! (1/n)

(Written in #Silice, running on @1bitsquared icebreaker + VGA PMOD, intro only, no audio) 2/ Another World by @EricChahi was one of my favorite #Amiga500 games. It's a great game with beautiful polygon-based graphics. Its architecture is also fascinating: the whole game runs in a custom VM

As the game turned 31 I thought a hardware version would make a great present!
Aug 30, 2022 23 tweets 12 min read
Q5K: Quake level viewer in 5K LUTs on a low cost, low power ice40 up5k #fpga! Custom #GPU, @risc_v CPU and SOC, capable of rendering #Quake's level with lightmaps.
How? Thread 👇

(Written in #Silice, here running on the #mch2022 badge fpga) The (tiny) GPU is my DMC-1 (Doom-Meets-Comanche) GPU, which also powers the Doomchip-onice demos (remember? Doom with a terrain!!).

It targets the ice40 UP5K, an entry-level fpga with great support from the Open Source toolchain #yosys/#nextpnr.
2/n
May 10, 2021 17 tweets 11 min read
How much DooM can fit in a USB port? Quite a bit it turns out! A minuscule #Fomu #fpga board hosts my hardware/software re-implementation of the DooM render loop in the confines of a USB port (uses ~4200 LUTs and < 128 kB of internal RAM). (1/n) This is a tiny piece of DooM in a 2.1x2.7 mm #fpga. That is pretty small! (can you see it below on the #Fomu board? you might have to zoom ...).

I created within a #riscv computer with specialized texturing and column drawing hardware. Designed to render DooM 1994 levels! (2/n)
May 8, 2020 9 tweets 4 min read
The DooM-chip! It will run E1M1 till the end of times (or till power runs out, whichever comes first).
Algorithm is burned into wires, LUTs and flip-flops on an #FPGA: no CPU, no opcodes, no instruction counter.
Running on Altera CycloneV + SDRAM. (1/n) Everything is described in a language I am working on: SDRAM controller, divider, BSP traversal, texture unit, etc.
Main renderer (w/o data) is 666 lines of code (!).
A great test case, made quite a few improvements, fixed some issues, learned a lot on CycloneV + Quartus.
(2/n)
Apr 27, 2020 4 tweets 3 min read
Wolfenstein 3D render loop in pure hardware! No CPU, no instruction pointer, no opcodes, only wires and flip-flops. Here runs on a Mojo V3 board (Xilinx Spartan 6) + SDRAM. Reading @fabynou black books while learning about #FPGA could only lead to this ;-)
(1/n) Implemented from scratch using my language, from the SDRAM double-framebuffer to the Wolf3D DDA algorithm (and this is the original one; fixed point, DDA loop with only adds and shifts, tangent table!). 320x200, 256 18-bits colors palette and VGA output -- old school!
(2/n)