Entry 123

Broken objects fly apart

2026-10-1613mrender

0x8004cdfc breaks an object into its faces. It walks the model's face sections from the first, but only flat textured ones (0x24 triangles, 0x2c quads, 32 faces a section at most), and stops at the first section of another kind. Each face is cut in four, then again, until no edge spans more than 1024 on an axis or more than the object's radius (+0x86):

• triangles by 0x8004c2e8, into the three corner triangles and the middle;
• quads by 0x8004b850, into four quads about the centre;
• texels and colours split at the same midpoints.

Each finished piece takes one of ten slots (0x800e2788, 96 bytes, 0x8004ab18); a piece with no slot left is not made. It flies as a flight (0x8004b580 for triangles, 0x8004b2b0 for quads):

• flags 0xc010700: kind 0, gravity 0x700, the world, a random spin axis;
• from its centre in the world, away from the point struck, at the caller's speed;
• 1000 ms;
• bounce 768 + (rand & 255), spin 3072 + (rand & 255);
• a spin axis of three rand bytes, normalised;
• the game's rand drawn six times a piece.

The port:

• world::shards cuts the faces.
• Flights::shatter launches the pieces with Skin::Shard(slot) and frees the slot when the flight ends.
• The game draws each piece as a one-face model, turned by the object's matrix and then by the flight's own angles.
• Game::shatter(placement, speed) breaks a placed object from its own place.

Callers ported:

• Level 15's ? boxes (0x8004d434): 100, with sound 114 and the burst.
• Level 6's breakable toys, template 1102 with template flag 1024, stood on (0x8005ac98): 100. The port played sound 173 at the player, but 0x8005ac98 plays it at the toy (a1 = +0xf8). Fixed.
• Level 6's toy bits, 0x80054ae0: five kind 5, flags 0x10505, sprites 421-425 by rand % 5, size and radius 600, speed rand % 400 (both from 0x800c41d4), within 1024 of up, 1000 ms, bounce 2048, spin 3391, face 0xc0800000, the toy's damage.
• Level 7's things Reptar takes, templates 401 and 795 (0x8005ac54): 200.

Test: level_15_mirrorland_is_won also checks that each box breaks into 1 to 10 pieces. Box template 1102 is 12 flat textured faces, radius 886.

Resolved from earlier entries:

• 29.1: the room lookup walks portals (worklog 122).
• 54.2, 110.2, 111.1: the signs' sparks (worklog 121).