game.clowns.geom

The procedural geometry kit the four clowns of GREASEPAINT are cut from. A lathe, a box, a tapered tube, a cone, a frilled ruff, a shoe, and the ability to stamp any of them into a growing buffer under a transform. Everything a performer is made of is one of those.

A geometry value is exactly the table renderer.mesh.create takes: { positions, normals, uvs, indices }.

Exports

• Geom.new() -> geometry — an empty accumulator.
• Geom.stamp(dst, src, xf) -> dst — copy src into dst under { pos, rot = {yaw, pitch, roll}, scale }. Angles are radians.
• Geom.stampFlat(dst, src, xf, u, v) — as stamp, then collapse the added vertices onto one texture coordinate, so a part that wears a painted material can point at a plain patch of it.
• Geom.lathe(profile, segments, opts) -> geometry — revolve { r, y } points running bottom to top. opts.uOffset turns the unwrap around the axis without turning the geometry; opts.vFromY maps v to height rather than arc length.
• Geom.spheroid(rx, ry, rings, segments, opts)
• Geom.tube(r0, r1, height, segments, opts) — capped, optionally bulged.
• Geom.limbDown(r0, r1, len, segments, opts) — the same tube built pointing DOWN from a joint at the origin, which is the rest pose an arm and a leg hang in.
• Geom.cone(radius, height, segments, opts)
• Geom.ruff(rInner, rOuter, thickness, lobes, segments) — a pleated collar, skinned on both sides.
• Geom.box(sx, sy, sz) — centred on x/z, sitting on y = 0.
• Geom.shoe(length, width, height) — far too long, turned up at the toe.
• Geom.upload(geometry, guid?) -> MeshHandle

Notes

• A ring puts x = r*sin(theta), z = r*cos(theta), so u = 0 faces +Z. The clowns face +Z (the audience), so a head takes uOffset = 0.5 to bring the painted face round to the front.
• Triangles wind counter-clockwise seen from outside. The engine reports a mesh whose winding disagrees with its own normals, which is the check to read after changing any index order here.
• Adapted from figures.geom in the ZeroMind world "Standing Ovation".