Firebird Quake 2

How it works

• The BSP becomes tables. A Quake 2 map (IBSP 38) is copied in lump by lump: FACES with their plane and texture mapping, FACE_VERTS (edges and surfedges resolved), NODES, LEAVES with their cluster and a decompressed PVS as a hex string, LEAFFACES, and the collision geometry Quake 2 ships instead of clipnodes: BRUSHES and BRUSHSIDES with their planes and contents, indexed through LEAFBRUSHES. The MD2 models contribute MODELS and their frame runs in ANIMS; the entity lump becomes MAP_ENTS.
• Collision is a recursive procedure. RHC is CM_RecursiveHullCheck: the moving box's extents push each split plane out, the segment is split at the plane and both sides are visited nearest first; in every leaf reached, CLIP_LEAF clips the segment against each brush whose contents match the mask (CM_ClipBoxToBrush). TRACE_MOVE runs it against the world and every door and platform (rotating doors are traced in their own rotated space) and tests monsters and the player with a Minkowski slab test. FLY_MOVE, WALK_MOVE (the 18-unit step), MOVE_STEP and PUSH_MOVE are g_phys.c in PSQL.
• The game is PSQL. Q2_TIC runs at 20 Hz: pmove's ducking, friction, acceleration, jumping and swimming, and the view's bob; doors and their teams, rotating doors, platforms, buttons, trains with path corners, rotating fans, timers; triggers (once, multiple, relay, always, key, counter, hurt, push), targets (speaker, explosion, splash, secret, goal, help, laser, changelevel), items from stimpacks to the power shield, the ten weapons from the blaster to the BFG10K, damage with armour and quad, gibs, and the monster AI of g_ai.c for the guards, enforcers, gunners, berserkers, flyers, parasites and the tank.
• The renderer is a query. FRAME_ALL finds the leaf and cluster the eye is in and, once per cluster, marks every face of every leaf whose cluster is in its PVS (Quake's visframe) with its plane and bounding sphere. A frame is then a scan of the marked faces with the back-face and frustum tests as expressions, aggregated with LIST() into one row of face ids; doors, platforms and the fan are brush models and add a row each at their own origin. The same result set carries the alias models and sprites in the PVS with their pose and frame, the light styles, the sounds and effects of the tic: one round trip per frame. The other renderer mode, FRAME_FACES, projects every vertex in SQL as well.
• JavaScript only paints. It rasterises the polygons with perspective-correct spans over a surface cache (the .wal texture × the lightmap, through colormap.pcx, as ref_soft did), blends translucent surfaces through the alpha map, draws the MD2 models with Gouraud light sampled from the lightmap below them, the sky box, particles, and the status bar from pics/. Sounds are rows in SOUND_EVENTS, spatialised with the Web Audio API; the map's looped speakers play at their origins. The soundtrack was CD audio: drop track02.ogg… into music/ and each map plays its worldspawn track; without them a synthesised drone fills in.

A port of Firebird Quake to Quake 2. The engine is Electric Firebird (firebird-wasm). The game data is the Quake 2 demo (id Software, 1997), which may be freely redistributed; drop in a registered pak0.pak to play the full game's base unit. Quake 2 is a trademark of id Software.