Posts: 430 from 2003/4/11
Very interesting to read that a kind of mini shader functionality already exists on R300 drivers.
There was indeed already some work done towards shaders for R300 (and R400, which is almost identical in that regard), but it never really left the experimental state. There's definitely lots of work still to be done to have it usable in general.Quote:
If somewhat old Radeons can have some support from R300 shader code allowing the missing functions to be implemented, I would bet for it: Besides non-duplicated work, probably it would increase performance leaving normal CPU for other tasks (not sure about that).
Everything that would be handled by implementing the fixed-function pipeline as shaders is already handled on the GPU today, so it wouldn't change anything from a performance point of view.
What could increase performance, and I want to make it clear that I'm speculating here, but for example in Doom 3, I imagine that it is doing interpolation between model frames currently. Without shaders, it has to do this with the CPU for every frame. With shaders it could do this interpolation on the GPU itself, which would not just save CPU power, but also allow for the models to be uploaded to the graphics card just once, instead of once every frame.Quote:
Dhewm3 by default uses GL_ARB_vertex_program and GL_ARB_fragment_program extensions.
The rest of needed functionalities are located in RenderSystem_init.cpp and draw_arb2.cpp sources.
Thank you :)Quote:
It was not my intention to push developers to a humongous work but my "potato port" might have some use after all.
Sometimes a push is required :) And I'm fairly sure plenty of people are enjoying your work too, so it's definitely useful!
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