Core Design

Responsibilities

• Represent small 3D meshes using vectors from Luna-Flow/linear-algebra.
• Keep transforms, normals, visibility, and projection-adjacent math backend neutral.
• Preserve face topology while applying transforms to vertex data.

Invariants

• Geometry core must not depend on Char, ANSI output, terminal dimensions, or background patterns.
• Mesh factories return vertices centered around the origin.
• Quad faces are the canonical mesh topology; triangulation is a helper for raster backends.
• Closed primitive faces use outward-facing vertex winding so normal-based culling remains valid.

Limitations

• No scene graph, materials, textures, clipping, camera orientation, asset loading, physics, or BVH.
• Sphere caps are represented as degenerate quads so the current quad pipeline can remain simple.

Extension Points

• Extend Transform3 deliberately while preserving point/direction semantics.
• Add alternate mesh factories while keeping the same Mesh topology contract.
• Add non-TUI backends by consuming Mesh, Transform3, and projected vertices without changing core.