A vertex shader in GLSL (OpenGL Shading Language) is a fundamental component of modern graphics programming. It is a specialized program responsible for processing individual vertices of 3D models before they are rendered on the screen.
When rendering a 3D scene, the vertex shader takes input attributes, such as the vertex positions, normals, texture coordinates, etc., and applies transformations and calculations to manipulate these attributes. The vertex shader's primary role is to transform the vertices from their original 3D coordinates to their projected 2D positions on the screen, taking into account perspective, scaling, translation, and rotation.
Through GLSL, developers have precise control over how vertices are manipulated, allowing for complex geometric transformations, deformations, and animations. Additionally, vertex shaders can be used to perform lighting calculations, providing the necessary information to calculate how light interacts with the vertices to create realistic shading effects.
Vertex shaders play a critical role in modern graphics pipelines, enabling efficient and flexible rendering of 3D scenes on GPUs. They are often used in conjunction with fragment shaders, which handle pixel-level calculations, to create visually stunning and interactive 3D graphics in games, simulations, and other interactive applications.