Gpu Software any software directly interacting with GPUs?

[osknockout 0]

Ok, I know that there is a Brook language, Cg shader language, and even an OpenGL implementation of shaders but where's the actual stuff that directly programs GPUs? (Graphical Processing Units, basically the main processors of graphics cards) I've been looking around the net and I can't find software that directly interacts with GPUs -even if it is just ONE single video card- without using some sort of proprietary driver. So I'm asking the cliche question. "Is there anything out there?" - preferably something that is open source?

[fffanatics 0]

In order to program on the GPU you have to use Shaders. It is the only way to gain access to the GPU since the GPU is only used in certain phases of the Graphics Pipeline (soon to be extinct in DX10). To utilize the shaders, you will want to learn a higher level shading language like CG, HLSL, or GLSL depending on the language you are programming with aka HLSL works with DX, GLSL with OpenGL, and CG with either of them. Since the GPU performs all operations in parallel you have to make sure your code is parallelized. Then you have to make sure your data is stored in a texture so that the GPU can access it and store it in the video memory. These are very advanced topics so before you even try to do something like this, learn how to use shaders in a simple graphical way like adding a glow to a mesh or something like that just so you know how they work.

[osknockout 0]

Ok, that makes sense. But is there no low-level shader language?- I know nVidia has this 'nvasm' program to compile some sort of assembly but it only goes into DirectX -I believe- and that only bymeans of VC++.I'm looking for some way to program the GPU by direct manipulation instead of having to go through some high-level programming language or such.But in case there is none ... which is probably very likely, how would I even start to program shaders in say GLSL?