Enabling Selective Surface-Based Collision

ObjectMeshStatic box1; 
ObjectMeshStatic box2;
ObjectMeshStatic plane;

/// function, creating a named box of a specified size and color at pos
int create_box(Object &OM, string name, Vec4 color, Vec3 size, Vec3 pos)
{
	// creating an auxiliary mesh with a box surface
	Mesh meshbox = new Mesh();
	meshbox.addBoxSurface("box_surface", size);

	// creating a static mesh object using an auxiliary mesh and setting parameters
	OM = new ObjectMeshStatic(meshbox);
	
	OM.setWorldTransform(translate(pos));
	OM.setMaterial("mesh_base", "*");
	OM.setMaterialParameterFloat4("albedo_color", color, 0);	
	OM.setCollision(1, 0);
	OM.setName(name);	

	// assigning a rigid body with our object
	BodyRigid body = class_remove(new BodyRigid(OM));

	// creating a box shape and assigning it to the rigid body of our object	
	ShapeBox shape = class_remove(new ShapeBox(size));
	body.addShape(shape,translate(0.0f, 0.0f, 0.0f));

	// deleting the auxiliary mesh
	delete meshbox;
	
	return 1;
}

/// function, creating a named plane having a specified width and height at pos
int create_plane(Object &OM, string name, double width, double height, Vec3 pos)
{

	// creating an auxiliary mesh with a plane surface
	Mesh meshplane = new Mesh();
	meshplane.addPlaneSurface("plane_surface", width, height, 1.0f);

	// creating a static mesh object using an auxiliary mesh and setting parameters
	OM = new ObjectMeshStatic(meshplane);
	
	OM.setWorldTransform(translate(pos));
	OM.setMaterial("mesh_base", "*");
	OM.setMaterialParameterFloat4("albedo_color", Vec4(0.0f, 0.0f, 1.0f, 1.0f), 0);
	OM.setCollision(1, 0);
	OM.setName(name);	

	// deleting the auxiliary mesh	
	delete meshplane;
	
	return 1;
}

int init() {
	
	// setting up a player
	Player player = new PlayerSpectator();
	player.setPosition(Vec3(0.0f, -6.0f, 12.5f));
	player.setDirection(Vec3(0.0f, 1.0f, -0.4f));
	engine.game.setPlayer(player);

	// creating a scene: two boxes and a plane
	create_box(box1, "Box 1", Vec4(1.0f, 1.0f, 0.0f, 1.0f), Vec3(0.5f), Vec3(1.5f, 0.0f, 12.0f));
	create_box(box2, "Box 2", Vec4(1.0f, 0.5f, 0.1f, 1.0f), Vec3(0.5f), Vec3(-1.5f, 0.0f, 12.0f));
	create_plane(plane, "Plane", 10.0f, 6.0f, Vec3(0.0f, 1.0f, 10.5f));

	// setting shape collision mask for the first box  [00000000000000000000000000000010]
	box1.getBody().getShape(0).setCollisionMask(2);

	// setting shape collision mask for the second box  [00000000000000000000000000000001]	
	box2.getBody().getShape(0).setCollisionMask(1);
	
	// setting collision mask for the plane surface  [00000000000000000000000000000010]
	plane.setCollisionMask(2, 0);
	
	return 1;
}			

int shutdown() {

	// memory cleanup
	delete box1;
	delete box2;
	delete plane;
	
	return 1;
}