vertexdata

Vertexdata refers to the per-vertex information that defines the properties of a vertex within a 3D mesh. In graphics pipelines, each vertex carries a set of attributes that the vertex shader uses to determine position, shading, and texture placement. Common attributes include position, normal, color, and texture coordinates, with additional data such as tangent and bitangent for normal mapping, and bone weights and indices for skeletal animation.

Typical vertex attributes

A minimal vertex might include position (three components, often float), while richer datasets add normal (three components), color (three or four components), and texcoord (two components). Extra attributes frequently used in modern rendering include tangent and bitangent vectors, which support advanced lighting techniques, and skinning data (bone indices and weights) for character animation.

Organization and memory layout

Vertex data can be stored in interleaved form, where all attributes for a vertex are placed contiguously in a single buffer, or in separate buffers for each attribute. The memory layout is described by stride (the total size of a vertex) and per-attribute offsets. Proper alignment and packing influence bandwidth and performance on the GPU.

Usage in rendering

During rendering, vertex data is uploaded to the GPU via vertex buffer objects. A vertex array object or equivalent describes how to interpret the buffers, binding attribute locations in shaders to buffers with specific formats. The pipeline reads per-vertex data in the vertex shader, and its results feed later stages. Instanced rendering can reuse the same vertex data with divisors to scale draws.

Formats and considerations

Vertex data originates from 3D models and generation pipelines. The choice of attributes and data types affects memory footprint and bandwidth. Float-based formats are common, with precision and padding considerations impacting performance on target hardware.