How is OpenGl implemented in the operating system?

Question

I am learning linux and the Graphical API, however I am confused about how opengl is implemented on operating systems. Is this just a collection of libraries that use the kernel to “talk” with your graphics card about which pixels are colored or not? if so, then I don’t know where the pipeline goes - like 3D raster scenes and the geometry of the shader effect.

And how does the GPU support shader languages ​​from both DX and OGL? - and where do the shader languages ​​really fit? - are they compiled or interpreted at runtime?

I do not have much experience with the graphics API, despite using multiple game engines - usually nitty gritty is much lost with several levels of abstraction.

Answer 1

I explained it in detail here: fooobar.com/questions/79344 / ... and here fooobar.com/questions/303821 / ...

Answer 2

I can’t talk about how the API is implemented.

But I know from experience that shaders are compiled. Therefore, you compile them and send them to your GPU, where they are executed.

Answer 3

At least on most typical graphics cards, most of the OpenGL pipeline (fixed or programmable) is implemented in the graphics hardware itself. This is more related to DirectX (i.e. DirectX lacks a bit of functionality in OpenGL that is not directly supported by current hardware).

Shaders are usually compiled. The graphics card has a special processor (or, often, more than one), so the compiler takes input in the shader language and turns it into assembly language for this processor, as does the C compiler for the CPU. Support for different input languages ​​is not much different from a single processor that supports input in C, C ++, Pascal, Fortran, Cobol, etc.