Module lines 

The world-space line segment any system can submit for a frame: a trajectory arc, a tether or beam, a patrol path, the editor’s origin axes. Lines are scene geometry, not overlay, so the depth-tested pass occludes them behind whatever is in front of them.

build_vertices expands each segment into the camera-facing ribbon the line pass rasterises.

Structs

Line

One world-space line to draw this frame. Colour is per endpoint, so a line that fades out with distance is a single request with a transparent far end.

LineCamera

The camera the expansion projects against. view is the world-to-view matrix the frame renders with (column-major, view[col][row]) and cam_pos its world-space position: in a camera-relative world both are the rebased pair, so callers must express their lines in that same space.

Functions

build_vertices

Expand lines into the ribbon triangles the line pass draws. Segments wholly behind the near plane, degenerate segments, and fully transparent segments contribute nothing, so an empty result means the pass can be skipped entirely.

build_vertices_into

build_vertices, writing into out (cleared first) so a per-frame caller reuses its buffer.