Backend TUI Design

Responsibilities

• Convert projected triangles into terminal characters.
• Own Z-buffer, shade ramp, background pattern, and terminal y-scale correction.
• Keep tests behavioral instead of snapshotting full ASCII frames.

Pipeline

DrawList
  -> terminal y-scale adjustment
  -> shade ramp
  -> triangle rasterization with perspective-correct depth
  -> FrameBuffer
  -> String

Limitations

No clipping, textures, smooth normals, or anti-aliasing.