fragmentshaderen

Fragment shaders (fragmentshaderen) are programs that run on the GPU to determine the final color and other attributes of individual fragments produced by the rasterization process. They are part of the programmable graphics pipeline, executed after vertex shading and primitive assembly, and before the final framebuffer write. For each fragment, the shader receives interpolated data from the vertex stage (such as texture coordinates and normals), as well as uniform inputs and texture samplers. The shader outputs at least a color value, and may also write depth or stencil information if the pipeline allows.

Typical use cases include texture sampling, lighting calculations, color and alpha blending, procedural effects, and post-processing. Fragment shaders can implement per-fragment lighting models (such as Phong) or physically based rendering (PBR) workflows, and can perform texture lookups across multiple maps (diffuse, normal, specular, metallic, roughness). They can also implement screen-space effects like bloom, ambient occlusion, and tone mapping in post-processing passes.

Languages and APIs: Fragment shaders are written in shading languages such as GLSL for OpenGL and WebGL, HLSL for Direct3D, Metal Shading Language for Apple's Metal, or SPIR-V-based forms for Vulkan. They are compiled for the target GPU architecture and linked into shader programs.

History and impact: Fragment shaders emerged in the 1990s with programmable GPUs and became essential for modern real-time graphics, enabling complex lighting, material appearance, and visual effects with per-pixel precision.