Triangle Meshes

Planar Polygons

• A triangle (3 vertices) is always planar
• Polygons with >3 vertices may not be planar

Triangulation

Most GPUs are optimised for triangles. Polygons with more vertices are split into triangles.

Why triangles?

• Always planar
• Convex (easy to fill)
• Simple interpolation
• Hardware acceleration

Triangle Mesh Indexing

For efficient storage:

• Vertex array: Unique vertex positions
• Index array: Which vertices form each triangle

Example: A cube has 8 vertices but 12 triangles (36 indices with sharing, or 24 vertices without).

Summary

• Triangles are always planar; other polygons may not be
• GPUs are optimised for triangles
• Indexed meshes reuse vertices for efficiency