Physics Constraint Hinge

App: apps/physics_constraint_hinge/

Demonstrates a hinge constraint: a door body anchored at its hinge point. Press Space to apply an impulse to a sphere that pushes the door open. Uses an FPS camera (WASD + mouse look) loaded from a blend.

Run from root

% ./plume3d physics_constraint_hinge

Controls

Key	Action
WASD	Move FPS camera
Mouse drag	Look around
Space	Launch sphere / push door

What it does

• Loads Models/HingeExample.blend and instantiates GameCamera, GameLight, Environment (static walls/floor), Door (hinge-constrained dynamic body), and Sphere.
• Finds the door node by Scene.findNodeById("door").
• Space launches the sphere toward the door; the hinge constraint limits rotation to one axis so the door swings open.
• Uses Physics.addImpulseAtPoint to apply an off-center impulse that creates swing torque.
• FPS camera from blend via FPSCamera.fromCamera.
• Shadow mapping enabled.

Key pattern

// Apply impulse at a point offset from door center
if (Input.keyJustPressed("space")) {
    var pos = _doorNode.getPosition()
    Physics.addImpulseAtPoint(_doorNode,
        0, 0, -50,               // impulse direction
        pos[0] + 2, pos[1], pos[2])  // off-center point
}

Blend setup

Create Models/HingeExample.blend with the Plume3D addon:

Object	Class	Rigid Body	Notes
Environment	Environment collection	Static walls/floor	—
Door	Door object	Active, Box	Add a Rigid Body Constraint: Hinge, anchored at door edge
Sphere	Sphere object	Active, Sphere	Launched by Space
Camera	GameCamera	—	Tag: game_camera
Light	GameLight	—	Tag: game_light

APIs

• Physics — addImpulseAtPoint, addImpulse.
• Scene — findNodeById.
• Resource — loadBlend.
• Graphics — setLights, setShadowMappingEnabled.