Entry 104

Thrown things bounce; the can comes back

2026-10-154mplay

Filescrates/rugrats/src/world/game/things.rs crates/rugrats/src/world/game/mod.rs crates/rugrats/tests/play.rs

40.1 left the can bouncing back into Tommy. The oracle (level 9 doc, "The flight") shows the can hit Mr. Friend (100 -> 70), bounce off him and come back into Tommy (Damage(player, player, 30), 255 -> 225). The port's flights stopped dead on any hit.

What the original does (0x80087594, the world path of flights without 0x10000000):

• An object or world hit reflects off the surface's normal (0x8007666c), unless the flight was moving away from it.
• The speed afterwards is (|v| - 95) * bounce >> 12. The bounce is the object's +0xa2, from template +0x36 clamped to 4095: the can 3200, the ball 2000, the pie 1500, most things 0.
• Slower than 95 + 382 with a floor under it (0x80087414), it stops.
• An object hit on this path damages any class 1 object, the player included (0x80087924), which is how the can hurts Tommy.

In the port (things.rs):

• rebound is the reflection and speed.
• A wall hit takes its normal from the segment test (99), or from the axis moved along when that does not stop.
• A body's normal is the face of its bounds cube the thing came at.
• Each thing remembers its last hit (record +0x98), so it does not strike the same body twice, and whether it bounced.
• A bounced thing of a template with +0x30 not 1 (not a ball) that reaches Tommy hurts him by its damage.
• Templates with no bounce drop as before.

The test level_9_a_can_bounces_back throws a can at Mr. Friend 1500 away. He loses 30, the can comes straight back, and Tommy loses 30, as in the oracle.