Code review flagged two latent correctness bugs in Pick:
1. The single t = -b - sqrt(d) intersection skipped entities whose
5m bounding sphere contained the ray origin. Realistic at
point-blank range — if the player stands within ~5m of a door,
the near-plane sits inside the door's bounding sphere and the
door becomes unpickable. Standard fix: when t_near < 0 fall
through to t_far = -b + sqrt(d) (the sphere exit point).
2. The discriminant formula assumes |direction| = 1. BuildRay
currently normalizes so the assumption holds at the wire, but
the contract wasn't documented. Added an explicit
<param name="direction"> note.
New test Pick_RayOriginInsideEntitySphere_StillReturnsServerGuid
covers the inside-sphere case. Suite: 9/9 WorldPicker tests pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Pick(origin, direction, candidates, skipServerGuid, maxDistance)
to AcDream.Core.Selection.WorldPicker. Iterates candidates, skips
entities with ServerGuid==0 (atlas/dat-hydrated statics — no server
identity) and the caller's skipServerGuid (the player self).
Geometric ray-sphere intersection at 5m radius (matches
WorldEntity.DefaultAabbRadius). Returns the nearest hit's ServerGuid
within maxDistance (50m default), or null on miss.
6 xUnit tests added: hit, miss, two-in-line-returns-closer, skip-guid,
skip-zero-server-guid, beyond-max-distance.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
New AcDream.Core.Selection.WorldPicker static helper. BuildRay
unprojects pixel (mouseX, mouseY) through a view+projection matrix
pair into a world-space (origin, direction) ray. Used by
GameWindow.OnInputAction to drive entity picking on click.
Pure math, no state, no DI. Composes view*projection (System.Numerics
row-vector convention, matching the rest of acdream's camera path —
see GameWindow.cs:6445 FrustumPlanes.FromViewProjection). 2 xUnit
tests cover center-of-viewport (forward ray) and right-of-center
(positive-X deflection).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
