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Miloslav Ciz 2024-12-19 16:48:05 +01:00
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@ -262,7 +262,7 @@ On PCs the whole rendering process is hardware-accelerated with a [GPU](gpu.md)
GPUs nowadays are no longer just focusing on graphics, but are kind of a general device that can be used for more than just 3D rendering (e.g. [crypto](crypto.md) mining, training [AI](ai.md) etc.) and can no longer even perform 3D rendering completely by themselves -- for this they have to be programmed. I.e. if we want to use a GPU for rendering, not only do we need a GPU but also some extra code. This code is provided by "systems" such as [OpenGL](opengl.md) or [Vulkan](vulkan.md) which consist of an [API](api.md) (an [interface](interface.md) we use from a [programming language](programming_language.md)) and the underlying implementation in a form of a [driver](driver.md) (e.g. [Mesa3D](mesa3d.md)). Any such rendering system has its own architecture and details of how it works, so we have to study it a bit if we want to use it.
The important part of a system such as OpenGL is its **rendering [pipeline](pipeline.md)**. Pipeline is the "path" through which data go through the rendering process. Each rendering system and even potentially each of its version may have a slightly different pipeline (but generally all mainstream pipelines somehow achieve rasterizing triangles, the difference is in details of how they achieve it). The pipeline consists of **stages** that follow one after another (e.g. the mentioned mapping of vertices and drawing of triangles constitute separate stages). A very important fact is that some (not all) of these stages are programmable with so called **[shaders](shader.md)**. A shader is a program written in a special language (e.g. [GLSL](glsl.md) for OpenGL) running on the GPU that processes the data in some stage of the pipeline (therefore we distinguish different types of shaders based on at which part of the pipeline they reside). In early GPUs stages were not programmable but they became so as to give a greater flexibility -- shaders allow us to implement all kinds of effects that would otherwise be impossible.
The important part of a system such as OpenGL is its **rendering [pipeline](pipeline.md)**. Pipeline is the "path" through which data go through during the rendering process. Each rendering system and even potentially each of its version may have a slightly different pipeline (but generally all mainstream pipelines somehow achieve rasterizing triangles, the difference is in details of how they achieve it). The pipeline consists of **stages** that follow one after another (e.g. the mentioned mapping of vertices and drawing of triangles constitute separate stages). A very important fact is that some (not all) of these stages are programmable with so called **[shaders](shader.md)**. A shader is a program written in a special language (e.g. [GLSL](glsl.md) for OpenGL) running on the GPU that processes the data in some stage of the pipeline (therefore we distinguish different types of shaders based on at which part of the pipeline they reside). In early GPUs stages were not programmable but they became so as to give a greater flexibility -- shaders allow us to implement all kinds of effects that would otherwise be impossible.
Let's see what a typical pipeline might look like, similarly to something we might see e.g. in OpenGL. We normally simulate such a pipeline also in [software renderers](sw_rendering.md). Note that the details such as the coordinate system [handedness](handedness.md) and presence, order, naming or programmability of different stages will differ in any particular pipeline, this is just one possible scenario: