Replaces M2's single hardcoded NDC-space triangle with a real perspective
pipeline: ICameraService/CameraService (fixed camera at (0,3,6) looking at
the origin), a QuadRenderer marker component, and a Draw() that iterates
world.Query<QuadRenderer>() to draw every such GameObject at its own
WorldMatrix. Needed as the foundation for M3's gizmos, which have to map
a screen-space drag onto a real 3D axis — a 2D quad and no camera can't
support that.
Two real bugs found and fixed empirically, not designed in from the start:
- SystemAccessScope correctly threw on Draw() querying QuadRenderer without
declaring Reads<QuadRenderer>() on its Schedule.Add registration — the
safety net catching a real omission, exactly as designed.
- UniformMatrix4 needed transpose:true, not false. System.Numerics.Matrix4x4
is row-major in memory; glUniformMatrix4fv with transpose=GL_FALSE reads
that layout as column-major instead. With transpose=false the quad simply
didn't render — no error, no crash, just a blank screen. Confirmed via a
correctly perspective-foreshortened, texture-mapped quad after the fix.
Also adds samples/WindowDemo/scene.json (a single Quad GameObject with a
QuadRenderer) so the new pipeline has something real to draw, loaded via
the existing --scene flag.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N1qPfzq8TDCUMFMV3UwV5N
