Replace flat mesh rendering of additive/mod blend batches (blendMode >= 3)
with camera-facing point sprites using a soft radial gradient texture and
additive blending. Adds M2 particle emitter infrastructure (structs, shader,
parsing stubs) but disables emitter parsing — the assumed 476-byte struct
size is wrong for WotLK 3.3.5a, causing misaligned reads that explode RAM.
Water/lava batches in fountain and Ironforge M2 models use non-opaque
blend modes (alpha, additive) defined in the M2 material table. Without
parsing these, they rendered as solid surfaces extending visibly beyond
their containers. Now each batch looks up its blend mode from the
material array and sets the appropriate GL blend function.
Parse M2TextureTransform entries and texture transform lookups from the
M2 binary, then apply per-batch UV offsets in the vertex shader using
the existing animation time base and global sequence durations.
M2 batches have a geosetIndex field that determines the geoset group for
filtering (0-18=body, 1xx=hair, etc.). We were incorrectly using submeshId
from the submesh struct instead. Now properly stores and uses geosetId.
- Parse global sequence durations from M2 binary and use them in bone
interpolation so torches, candles, and other env doodads animate.
- Add UV scroll shader effect for smoke models (HouseSmoke, SmokeStack)
as a workaround for unimplemented M2 particle emitters.
- Tighten WMO floor probe heights to prevent multi-story buildings from
returning the wrong floor, fixing player clipping through inn floors
and camera locking onto the second floor.
- Use player ground level as reference for camera orbit floor collision
so the camera doesn't fight upper floors in buildings.
