User reported intermittent selection — 'sometimes can be selected,
sometimes not'. Cause: WorldEntity.Position is at FEET level (Z=ground
for standing humanoids), so a 0.7m sphere centred there only covered
the lower legs. Clicks on chest (Z≈1.2m) or head (Z≈1.7m) missed
because the closest-approach distance from the cursor ray to the
feet-centered sphere exceeded the radius.
Fix:
- Sphere centre now defaults to position.Z + 0.9 m (humanoid
mid-body). New optional verticalOffsetForGuid callback overrides
per entity.
- Default radius bumped 0.7 → 1.0 m to match the new sphere
placement (1.0 m at 0.9 m height covers a 1.8 m humanoid from
shin to top-of-head).
GameWindow.PickAndStoreSelection wires the callback:
- Creatures (ItemType.Creature flag): vz = 0.9 m (humanoid centre)
- Large flat objects (BF_DOOR | BF_LIFESTONE | BF_PORTAL |
BF_CORPSE): vz = 1.0 m + radius 2.0 m (mid-door/lifestone)
- Everything else (ground items): vz = 0.2 m (just above feet)
Existing 9 WorldPicker tests still pass — their head-on ray geometry
doesn't depend on the vertical offset.
Visual test surfaced three follow-ups:
1. Square box, not 1:2 rectangle.
WidthHeightRatio: 0.5 → 1.0. Retail's Vivid Target Indicator draws
a square; the earlier humanoid-aspect ratio looked wrong for
non-humanoids and didn't match retail screenshots.
2. Large flat objects (doors / lifestones / portals / corpses)
weren't selectable with the new tight 0.7 m pick sphere.
WorldPicker.Pick now takes an optional radiusForGuid callback so
the host can per-entity decide a larger radius. GameWindow's pick
site supplies a lambda that bumps to 2.0 m for any entity with
BF_DOOR (0x1000), BF_LIFESTONE (0x4000), BF_PORTAL (0x40000), or
BF_CORPSE (0x2000) set in ObjectDescriptionFlags. Default stays
at 0.7 m for humanoids and items.
3. New [B.7] pick-info diagnostic on each successful pick:
[B.7] pick-info guid=0x... itemType=0x... pwd=0x... color=(r,g,b)
Lets us verify e.g. whether a 'green NPC' really is server-side
flagged as Vendor (BF_VENDOR=0x200, retail-defined green) vs a
bug in our colour lookup. The pwd bit table is acclient.h:6431-
6463 — same flags retail's gmRadarUI::GetBlipColor branches on.
Note: textured retail-sprite corner triangles remain a B.7 follow-up
deferred per the spec. MVP uses procedural fills.
User-observed bug: 'I selected a retail player once, now I cant select
anything else.' Cause: the 5 m fixed pick sphere covered most of the
visible area around an entity, so once the cursor was anywhere near an
NPC or player, every subsequent click resolved to that same NPC/player
instead of the actual cursor target.
0.7 m roughly matches the actual hitbox radius of humanoid bodies and
most pickable items. Clicking on the entity's silhouette still hits;
clicking next to it or through it to a closer target now correctly
picks the closer target.
Existing 9 WorldPicker unit tests all pass — they tested geometric
behaviour at picked test radii, not the literal 5 m constant.
Follow-ups (deferred to a future picker phase):
- Per-itemType radius (tighter for tapers, looser for chests).
- Priority sorting at equal hit-distance (items beat NPCs).
- Ray-vs-actual-mesh test instead of bounding sphere.
Together with B.7's target indicator (corner triangles, c7e5f9f /
4bc95ec) this gives the user both 'I can hit what I'm aiming at'
AND 'I can see what I just hit' — fixes the over-pick at the source
plus surfaces it visually when it does still happen.
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>
