This is the public release of an old project of mine, that I worked on from Sept 2018 to Jan 2023.
Along with the specification, this repo contains the assembler and the VM. I have also made a programming language along with graphics API libraries and other things, but it is hidden for now as I am using it to develop an OS on my new ISA. Piculet is more of bytecode than an ISA, and it's not a very good one either. Nonetheless, it is my most impressive (nearly) complete project.
This was my main hobby project of mine for a few years. I do not write my code like this anymore and I'm aware that this project has various flaws.
I am releasing it simply because it's an interesting project. A lot of very specific design choices were made when I was working on the graphics side of the spec, so many that I cannot remember them all. Think: stuff like 7 instead of 8 min supported texture units so that an extra would be available if an early version GLES implementation having only 8 TUs wanted emulate MRT support by repeating render passes multiple times. A LOT of work went into designing the graphics API, which is quite closely modeled after modern graphics APIs.
In addition to the public maybe finding it fun to play with, releasing it here in this complete, single repo format allows me to feel some kind of closure with this project that I've long moved on from.
For the specification, all rights are reserved. You can implement a VM based on it, but not for commercial use.
For the VM, assembler, and code examples, the MIT license applies. I do not care what you do with it as long as attribution is given.
Not all features defined by the spec are implemented. Mostly just the minimal feature set is supported. Regardless, that is quite a large amount of stuff.
Compute shaders are supposed to be implemented (by GPU or emulation on CPU), but I never implemented them.
To build the assembler, run:
cc asm.c -o asm
To then run an assembly file through the assembler, run:
./asm file.s
This will result in an out.bin file being created.
Additionally, to output all assembled shaders into shader bytecode files
(_shader0, _shader1, ...), run:
./asm file.s -s
To print unused label warnings, run:
./asm file.s -v
Building the VM is easy. GLFW 3 and OpenGL 3.1+ are required. Tested with clang and gcc compilers on Arch, Ubuntu, and FreeBSD.
cc vm.c -o vm -lGL -lglfw -lm
The VM can then be run as ./vm file, where the file specified is the program
to run.
The demos folder contains a few demos, which are really just old hand-written
assembly programs that I was using for testing the VM. push.s, quad.s, and
texture.s examples all use a push constant for supplying data to the shader.
uniform.s uses a UBO for supplying data to the shader.
The assembly files were not cleaned up - copied exactly as they were in my old folders. There are commented out bits of code (mostly in shaders) that do extra stuff which I left in because it gives you more view of what the shader assembler looks like. There are also many comments that make no sense because they were simply notes for myself when I was writing the programs.
Yes, unfortunately that's all the documentation I have for this at the moment. This isn't really a project I work on anymore. Read the spec if you want more info, that's the big thing here. I will consider adding more here in the future.