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rswinkle | 3 years ago

Depends on how you define castrated. It's not like using C or C++ is really limiting and using a C++ math library (like my own rsw_math or more complete glm) lets you basically write it in GLSL. It's not like there's anything you can't do.

And the only math from Bellard's TinyGL that I use is his clipping code, maybe 80 lines of code give or take. Not to diminish Bellard at all, if anything I'm saying any problems with PortableGL are mine not his.

discuss

sylware|3 years ago

My bad, I used "castrated", it is not what I really wanted to say. I should have said a subset of opengl features. Namely, it is not a software GL implementation you can run an opengl4 3D game on (only those horrible c++ diarehas which are llvm with things like llvmpipe or the other one from intel are supposed to be able to do so).

rswinkle|3 years ago

Yeah PortableGL will never be completely fully featured, not even for OpenGL 3.3 since I'll definitely never do the geometry shader and probably not the transform feedback. But specifically it'll never have the earlier immediate mode stuff, or some of the big 4.0 stuff like the tessellation shaders. I have been meaning to add the DSA functions where they make sense. They'd be really simple to implement.

Actually a few days ago someone sent me a pull request adding an interesting project to my README

https://github.com/rswinkle/PortableGL/commit/e0652b4dff266d...

So now if I were to try to sum up all the OpenGL software implementations I can think of,

TinyGL (and modern improved forks) = OpenGL 1.1-1.3 ish

osmesa = OpenGL 2.1 using Mesa 7.0.4's swrast

PortableGL = OpenGL 3.x-ish

Mesa = 2 software renderers still included, gallium based softpipe and llvmpipe and I think one or both support the latest OpenGL 4.6 but I could be wrong. swrast and Intel's gallium/llvm based OpenSWR have both been removed from mainline Mesa, and the latter only supports 3.3 core-ish (https://www.openswr.org/)

I'm sure there are others out there. I've actually never tried to use "Stand alone" Mesa. I really should to see how it performs if nothing else, but I still say nothing beats the single header library for ease of use.