Proper handling of rigidbody associated with an entity and notifying it of movement or collision

README.md

@@ -155,7 +155,7 @@
 
 - ## TODO
 
-	- Proper physics time-step and speed
+	- Update physics if entity position/rotation/scale etc are changed
 	- Fix lights type not being correctly saved/loaded from file
 	- Physics Trimesh support
 	- Debug physics mesh drawing
@@ -356,3 +356,5 @@
 	* Implement necessary changes to run Soloud on linux
 	* Moved third party libs/include directories into root/lib and root/include. Put common includes like header-only libs into root/include/common and others which require platform specific stuff into root/include/linux etc.
 	* Got rid of pkg-confg and system-installed SDL2 dependancy on linux and instead put custom compiled SDL libs in libs folder similar to how we're handling it in windows
+	* Proper physics time-step and speed
+	* Proper handling of rigidbody associated with an entity and notifying it of movement or collision

src/common/common.h

@@ -20,6 +20,7 @@ struct Sound_Source_Buffer;
 //Physics Decls
 typedef void* Rigidbody;
 typedef void (*RigidbodyMoveCB)(Rigidbody);
+typedef void (*RigidbodyColCB)(Rigidbody, Rigidbody);
 
 // Function Pointer decls
 typedef void (*Keyboard_Event_Func)     (int key, int scancode, int state, int repeat, int mod_ctrl, int mod_shift, int mod_alt);
@@ -64,10 +65,13 @@ struct Physics_Api
 	void      (*body_rotation_get)(Rigidbody body, float* x, float* y, float* z, float* w);
 	Rigidbody (*plane_create)(float a, float b, float c, float d);
 	Rigidbody (*box_create)(float length, float width, float height);
-	void      (*body_set_moved_callback)(Rigidbody body, RigidbodyMoveCB callback);
+	void      (*body_set_moved_callback)(RigidbodyMoveCB callback);
+	void      (*body_set_collision_callback)(RigidbodyColCB callback);
 	void      (*body_kinematic_set)(Rigidbody body);
 	void      (*body_mass_set)(Rigidbody body, float mass);
 	float     (*body_mass_get)(Rigidbody body);
+	void*     (*body_data_get)(Rigidbody body);
+	void      (*body_data_set)(Rigidbody body, void* data);
 };
 
 struct Sound_Api

src/game/main.c

@@ -134,7 +134,10 @@ int main(int argc, char** args)
 				.body_kinematic_set          = &physics_body_kinematic_set,
 				.body_mass_set               = &physics_body_mass_set,
 				.body_mass_get               = &physics_body_mass_get,
+				.body_data_set               = &physics_body_data_set,
+				.body_data_get               = &physics_body_data_get,
 				.body_set_moved_callback     = &physics_body_set_moved_callback,
+				.body_set_collision_callback = &physics_body_set_collision_callback,
 				.plane_create                = &physics_plane_create,
 				.box_create                  = &physics_box_create
 			}

src/game/physics.c

@@ -10,6 +10,8 @@ static struct
 	dSpaceID        space;
 	dJointGroupID   contact_group;
 	double          step_size;
+	RigidbodyColCB  on_collision;
+	RigidbodyMoveCB on_move;
 }
 Physics;
 
@@ -40,7 +42,6 @@ void physics_init(void)
 		dWorldSetLinearDamping(Physics.world, 0.00001);
 		dWorldSetAngularDamping(Physics.world, 0.005);
 		dWorldSetMaxAngularSpeed(Physics.world, 200);
-
 		dWorldSetContactMaxCorrectingVel(Physics.world,0.1);
 		dWorldSetContactSurfaceLayer(Physics.world,0.001);
 	}
@@ -60,19 +61,11 @@ void physics_cleanup(void)
 
 void physics_step(float delta_time)
 {
-	//if(delta_time <= 0.f) delta_time = Physics.step_size;
-	//dSpaceCollide(Physics.space, NULL, physics_near_callback);
-	//dWorldQuickStep(Physics.world, delta_time);
-	////dWorldStep(Physics.world, Physics.step_size);
-	//dJointGroupEmpty(Physics.contact_group);
-
 	int steps = (int)ceilf(delta_time / Physics.step_size);
-	//log_message("Num steps : %d", steps);
 	for(int i = 0; i < steps; i++)
 	{
 		dSpaceCollide(Physics.space, NULL, physics_near_callback);
 		dWorldQuickStep(Physics.world, Physics.step_size);
-		//dWorldStep(Physics.world, Physics.step_size);
 		dJointGroupEmpty(Physics.contact_group);
 	}
 }
@@ -171,7 +164,7 @@ void physics_near_callback(void* data, dGeomID o1, dGeomID o2)
 	int n = dCollide(o1, o2, MAX_CONTACTS, &(contact[0].geom), sizeof(dContact));
 	if(n > 0)
 	{
-		log_message("Collision!");
+		Physics.on_collision(b1, b2);
 		for(int i = 0; i < n; i++)
 		{	
 			//contact[i].surface.slip1 = 0.7;
@@ -206,12 +199,19 @@ Rigidbody physics_box_create(float length, float width, float height)
 	dBodySetAngularVel(body, 0, 0, 0);
 	dBodySetLinearVel(body, 0, 0, 0);
 	dBodySetTorque(body, 0, 0, 0);
+	dBodySetMovedCallback(body, Physics.on_move);
+
 	return body;
 }
 
-void physics_body_set_moved_callback(Rigidbody body, RigidbodyMoveCB callback)
+void physics_body_set_moved_callback(RigidbodyMoveCB callback)
+{
+	Physics.on_move = callback;
+}
+
+void physics_body_set_collision_callback(RigidbodyColCB callback)
 {
-	dBodySetMovedCallback(body, callback);
+	Physics.on_collision = callback;
 }
 
 float physics_body_mass_get(Rigidbody body)
@@ -226,6 +226,16 @@ void physics_body_mass_set(Rigidbody body, float mass)
 	dBodySetMass(body, &dmass);*/
 }
 
+void physics_body_data_set(Rigidbody body, void * data)
+{
+	dBodySetData(body, data);
+}
+
+void * physics_body_data_get(Rigidbody body)
+{
+	return dBodyGetData(body);
+}
+
 void physics_body_kinematic_set(Rigidbody body)
 {
 	dBodySetKinematic(body);

src/game/physics.h

@@ -18,11 +18,15 @@ void physics_body_rotation_set(Rigidbody body, float x, float y, float z, float
 Rigidbody physics_plane_create(float a, float b, float c, float d);
 Rigidbody physics_box_create(float length, float width, float height);
 
-void physics_body_set_moved_callback(Rigidbody body, RigidbodyMoveCB callback);
+void physics_body_set_moved_callback(RigidbodyMoveCB callback);
+void physics_body_set_collision_callback(RigidbodyColCB callback);
 
 float physics_body_mass_get(Rigidbody body);
 void  physics_body_mass_set(Rigidbody body, float mass);
 
+void  physics_body_data_set(Rigidbody body, void* data);
+void* physics_body_data_get(Rigidbody body);
+
 void physics_body_kinematic_set(Rigidbody body);
 
 #endif

src/libsymmetry/entity.c

@@ -651,7 +651,36 @@ void entity_apply_sound_params(struct Entity* entity)
 }
 
 
-void entity_on_rigidbody_move(Rigidbody body_A, Rigidbody body_B)
+void entity_rigidbody_on_move(Rigidbody body)
 {
+	int id = platform->physics.body_data_get(body);
+	struct Entity* entity = entity_get(id);
+	vec3 pos = {0};
+	quat rot = {0};
 
+	platform->physics.body_position_get(body, &pos.x, &pos.y, &pos.z);
+	platform->physics.body_rotation_get(body, &rot.x, &rot.y, &rot.z, &rot.w);
+
+	quat_assign(&entity->transform.rotation, &rot);
+	transform_set_position(entity, &pos);
+}
+
+void entity_rigidbody_on_collision(Rigidbody body_A, Rigidbody body_B)
+{
+	struct Entity* ent_A = NULL;
+	struct Entity* ent_B = NULL;
+
+	if(body_A) 
+	{
+		int id_A = platform->physics.body_data_get(body_A);
+		ent_A = entity_get(id_A);
+	}
+
+	if(body_B) 
+	{
+		int id_B = platform->physics.body_data_get(body_B);
+		ent_B = entity_get(id_B);
+	}
+
+	if(ent_A && ent_B) log_message("Entity %s collided with Entity %s", ent_A->name, ent_B->name);
 }

src/libsymmetry/entity.h

@@ -141,6 +141,7 @@ bool           entity_write(struct Entity* entity, struct Parser_Object* object)
 struct Entity* entity_read(struct Parser_Object* object);
 const char*    entity_type_name_get(struct Entity* entity);
 void           entity_apply_sound_params(struct Entity* entity); // Convenience function to sync the data set in entity's sound_source with the actual sound source's instance
-void           entity_on_rigidbody_move(Rigidbody body_A, Rigidbody body_B);
+void           entity_rigidbody_on_move(Rigidbody body);
+void           entity_rigidbody_on_collision(Rigidbody body_A, Rigidbody body_B);
 
 #endif

src/libsymmetry/game.c

@@ -103,6 +103,8 @@ bool game_init(struct Window* window, struct Platform_Api* platform_api)
 	entity_init();
 	platform->physics.init();
 	platform->physics.gravity_set(0.f, -9.8f, 0.f);
+	platform->physics.body_set_moved_callback(entity_rigidbody_on_move);
+	platform->physics.body_set_collision_callback(entity_rigidbody_on_collision);
 	scene_init();
 	
 	/* Debug scene setup */
@@ -254,12 +256,15 @@ void scene_setup(void)
 	Rigidbody box = platform->physics.box_create(2.5, 2.5, 2.5);
 	platform->physics.body_position_set(box, 0.f, 50.f, 0.f);
 	platform->physics.body_mass_set(box, 10.f);
-	platform->physics.body_set_moved_callback(box, on_box_move);
+	platform->physics.body_data_set(box, (void*)suz_id);
+
+	/*Rigidbody plane = platform->physics.plane_create(0, 1, 0, 0);*/
+	Rigidbody ground_box = platform->physics.box_create(10, 10, 10);
+	platform->physics.body_position_set(ground_box, 0.f, 0.f, 0.f);
+	platform->physics.body_kinematic_set(ground_box);
+	struct Entity* ground = entity_find("Ground");
+	platform->physics.body_data_set(ground_box, (void*)ground->id);
 
-	Rigidbody plane = platform->physics.plane_create(0, 1, 0, 0);
-	//Rigidbody ground_box = platform->physics.box_create(1000, 1, 1000);
-	/*platform->physics.body_position_set(ground_box, 0.f, 0.f, 0.f);
-	platform->physics.body_kinematic_set(ground_box);*/
 }
 
 void debug(float dt)
@@ -1707,18 +1712,3 @@ struct Game_State* game_state_get(void)
 {
 	return game_state;
 }
-
-void on_box_move(Rigidbody body)
-{
-	struct Entity* suz = entity_get(suz_id);
-	vec3 pos = {0};
-	quat rot = {0};
-
-	platform->physics.body_position_get(body, &pos.x, &pos.y, &pos.z);
-	platform->physics.body_rotation_get(body, &rot.x, &rot.y, &rot.z, &rot.w);
-
-	quat_assign(&suz->transform.rotation, &rot);
-	transform_set_position(suz, &pos);
-
-	//log_message("Pos : %.3f, %.3f, %.3f", pos.x, pos.y, pos.z);
-}