vertexshader

A vertex shader is a programmable stage in a graphics processing unit (GPU) that processes each vertex of a 3D model as it moves through the rendering pipeline. It runs for every vertex and is responsible for transforming vertex attributes, such as position, normal, color, and texture coordinates, into data that the rest of the pipeline can use. The shader operates on input attributes and uniform values provided by the application and outputs data to the next stage, typically via per-vertex outputs that are interpolated across primitives.

In practice, a vertex shader performs several common tasks. It converts a vertex’s position from object space to clip space by applying transformation matrices (often model, view, and projection matrices). It can transform normals, perform skinning to support skeletal animation by blending bone transformations, and compute per-vertex lighting or other per-vertex data. It may also generate or modify texture coordinates, colors, or other vertex attributes that will be interpolated for fragment processing.

Inputs and outputs are defined by shading languages such as GLSL for OpenGL/WebGL, HLSL for Direct3D, or analogous languages in other APIs. Typical inputs include vertex attributes (position, normal, texcoord) and uniform variables (transformation matrices, lighting parameters). The primary output is the position of the vertex in clip space (gl_Position in GLSL) and a set of varying or out variables that pass data to the fragment shader after interpolation.

Vertex shaders are a core component of modern programmable graphics pipelines, replacing fixed-function vertex processing and enabling flexible effects, animation, and advanced rendering techniques across OpenGL, Direct3D, Vulkan, and Metal.