vec4vertexxyz

vec4vertexxyz is a term used in computer graphics to refer to a four-component vector that stores a vertex’s position in 3D space along with an additional component, typically designated as w. In many shading languages, vec4 is the standard type for such four-component data, and the name vec4vertexxyz is commonly used as a descriptive variable name for a position expressed in homogeneous coordinates.

The conventional interpretation is that the first three components correspond to x, y, and z, while the fourth component, w, is used to support homogeneous coordinate mathematics. For vertices, w is usually set to 1.0, which allows translation and other affine transformations to be applied through matrix multiplication. A typical usage is to construct the vector as vec4 vertexXYZ = vec4(position, 1.0);, where position is a vec3 holding the Cartesian coordinates. After transformation by a model-view-projection matrix, the result is used as the clip-space position, often assigned to gl_Position.

This approach provides a flexible way to handle vertex data in pipelines that rely on homogeneous coordinates. If w were 0, the vector would represent a direction rather than a position, which is common for normals or other directional vectors. The vec4form makes it straightforward to apply the same matrix math to both positions and related data when needed.

In practice, vec4vertexxyz is a naming convention rather than a standardized type. It appears in codebases as a clear, explicit container for 3D positions extended to a vec4, ensuring compatibility with traditional projection workflows.