hlsl2glslfork/README.md

HLSL to GLSL shader language translator

DX9 style HLSL in, GLSL / GLSL ES out.

A continued development from ATI's HLSL2GLSL. I'm changing it to make it work for Unity's use cases; might totally not work for yours!

For an opposite tool (GLSL ES to HLSL translator), look at Google's ANGLE.

Changes from original HLSL2GLSL 0.9

• Made it build with VS2008 on Windows and XCode 3.2 on Mac. Build as static library.
• Feature to produce OpenGL ES-like precision specifiers (fixed/half/float -> lowp/mediump/highp)
• Fixes to ternary vector selection (float4 ? float4 : float4)
• Fixes to bool->float promotion in arithmetic ops
• Fixes to matrix constructors & indexing (GLSL is transposed in regards to HLSL)
• Support clip()
• Support Cg-like samplerRECT, texRECT, texRECTproj
• Support VPOS and VFACE semantics
• Fix various crashes & infinite loops, mostly on shaders with errors
• Cleaner and more deterministic generated GLSL output
• Unit testing suite
• Simplified interface, code cleanup, unused code removal, merge copy-n-pasted code, simplify implementation etc.

Notes

• Only Direct3D 9 style HLSL is supported. No Direct3D 10/11 "template like" syntax, no geometry/tesselation/compute shaders, no abstract interfaces.
• I bumped into some issues of HLSL2GLSL's preprocessor that I am not fixing. Most issues were with token pasting operator. So I preprocess source using mojoshader's preprocessor. Grab latest from mojoshader hg, it's awesome!
• On Windows, the library is built with _HAS_ITERATOR_DEBUGGING=0,_SECURE_SCL=0 defines, which affect MSVC's STL behavior. If this does not match defines in your application, totally strange things can start to happen!
• The library is not currently thread-safe.

Status

Seems to work quite well for Unity's shaders. When/if we bump into any issues; we'll just fix them.

No optimizations are performed on the generated GLSL, so it is expected that your platform will have a decent GLSL compiler. Or, use GLSL Optimizer, we use it to optimize shaders produced by HLSL2GLSL; gives a substantial performance boost on mobile platforms.