Physics Stack

App: apps/physics_stack/

Demonstrates automatic rigid body stacking: a tower of dynamic cubes on a static floor, with contact events logged to the console when cubes collide. Bodies are created automatically from Blender’s Rigid Body settings on instantiation — no Physics.addDynamicBox calls needed.

Run from root

% ./plume3d physics_stack

What it does

• Loads Models/StackDemo.blend and instantiates GameCamera, GameLight, Environment (static floor), and stacked Cubes (dynamic rigid bodies).
• Registers Physics.onContactBegin to log every collision pair and contact point.
• Shadow mapping enabled: light.castsShadows = true, Graphics.setShadowMappingEnabled(true), Graphics.setShadowMapSize(2048).

Contact event registration

Physics.onContactBegin(_scene) { |nodeA, nodeB, px, py, pz, nx, ny, nz|
    Logger.info("Contact: %(nodeA.name) <-> %(nodeB.name) at (%(px), %(py), %(pz))")
}

Blend setup

Create Models/StackDemo.blend in Blender with the Plume3D addon:

Object	Class	Collision Layer	Rigid Body
Floor plane	in Environment collection	Floor	Passive, Box
Stacked cubes	StackedCubes collection	Boxes	Active, Box
Camera	GameCamera	—	—
Light	GameLight	—	—

game.toml

[Physics]
collision_layers = ["Default", "Floor", "Boxes"]
collision_matrix = [[0,0], [0,1], [0,2], [1,2], [2,2]]

APIs

• Physics — onContactBegin (contact event callbacks).
• Resource — loadBlend (bodies auto-created on instantiate).
• Graphics — setLights, setShadowMappingEnabled, setShadowBias, setShadowMapSize.
• Light — castsShadows.