Entry 10

Rooms drawn natively: blob meshes, the texture table, room centres, rugrats-viewer

2026-10-148mformatrenderdecomptoolingbuild

Filescrates/rugrats-data/src/level.rscrates/rugrats-render/src/rooms.rsrenderer.rscrates/rugrats-viewer/src/main.rs

rugrats-viewer 22 flies around database 22, the Pickles' house of the opening cinematic: staircase, hallway, the blue carpet, doors, the painted walls with their baked shading, all from the disc's data and drawn with wgpu. It is the first 3D the port draws.

The geometry, read from the hand-written renderer

The room renderer (draw_room, 0x80033818) tests each blob in a room's list against its bounding box (blob_visible, 0x80032cf4, eight corners through RTPT, out if all depths are 0 or less) and hands survivors to the hand-written renderer at 0x80010e14. A blob is a link word, the bounds, a vertex count, the offset of its faces, then 12-byte vertices (s16 x, y, z, pad; r, g, b and a one-shot brightening), then face sections u16 kind, u16 count: 0x61 quads of four u8 indices and a u32 texture word, 0x60 triangles of three indices, a pad byte (0xcd in all 13772) and the texture word, 0xff the end. A Python sweep over all 3083 blobs of the 31 readable LEVEL files found only those three kinds and ended every blob exactly on its 0xff; every_level_parses_and_its_faces_name_its_textures now holds the Rust parser to the same.

The texture word's low half indexes a 12-byte table the renderer reads through its context (+0x58) and copies into the packet's uv slots word for word: u0 v0 CLUT, u1 v1 texture page, u2 v2 u3 v3, TEXPOS.DAT's layout. The cinematic never loads TEXPOS.DAT, and the LEVEL file's final section is 12-byte records: in every file the highest texture any face names is exactly that section's count less one (DB22: 205 of 206; DB15: 1030 of 1031). It is the room texture table. The texture image is DBnnA.RAW, uploaded whole by load_rooms to VRAM (0, 256), 576 x 256.

All of a database's blobs are centred on the origin; the 112-byte room record places them: +0x00 the room's centre (s32 x, y, z), +0x10 and +0x20 its bounds, +0x30 its portal count. DB22's room 0 is centred at (19456, -7168, 1536) with bounds (13312, -10240, 0) to (25600, -4096, 3072), and its blobs reach exactly +-6144, +-3072, +-2048.

The renderer, from hwtr

rugrats-render is hwtr's wgpu renderer unchanged where it is the console's: VRAM as an R16Uint texture, texture page and CLUT decoded in the fragment shader, texel times vertex colour over 128, colour 0 transparent, the four semi-transparency modes. Only the triangles are Rugrats': the first shot drew the floor and no walls, since the game's front faces (NCLIP positive, y down) are clockwise in the renderer's view; faces are now emitted 0 2 1 and 1 2 3.

Not yet ported: the depth cue beyond 8192, the near-face subdivision (the port draws with perspective-correct texturing, so subdivision has nothing to correct), objects, and the portal visibility walk.