Hello, After some messages on this list, I reconsidered my GSoC proposal and decided to give a try at an OpenCL state tracker. I will base my work on the Clover branch of Mesa.
I read its code, which is very well-done and clean, but I saw one big difficulty : I don't know how to translate LLVM IR to TGSI. The big problem is that TGSI is made mostly with OpenGL in mind. We can use it to decode video frames using vertex and fragment shader stages, but using it to run on the GPU the complex output given by LLVM, and without using any part of the OpenGL pipeline (OpenCL can be used to do mathematics, and that doesn't draw anything on the screen), is tricky. The problem is how OpenCL can upload data on the GPU and then download the computed results. One solution may be to create one or more textures containing the input data (maybe one texture by input data type), and then use a fragment shader to compute the resulting values and to put them in a render buffer that will never be drawn on screen but instead downloaded from the GPU and sent back to the application. I don't know if it would be possible to do things like that, especially considering that precise results across all graphics cards may be difficult to get with OpenGL. An other problem of this LLVM to TGSI conversion is that the TGSI instruction set is not completely implemented on all the pipe drivers, and that unimplemented instructions may be needed by a specific LLVM IR instruction. I'm open to any suggestion regarding this OpenCL state tracker. If you say it will be very difficult to do that during the summer, I think I will apply to work on the OpenGL 3+ support in Mesa (without doing a new state tracker) and the GLSL compiler. Best regards, Denis Steckelmacher. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
