reworked bouncing

src/physics_entity.c

@@ -26,16 +26,11 @@ void physics_entity_debug_draw(PhysicsEntity self) {
 }
 static  inline
 Vector _internal_calculate_contact_force(RigidBody* self, Contact* contact) {
-    Collision hit = contact->hit;
+    const Vector velocity = contact->hit.velocity;
-
+    const Vector normal = contact->hit.normal;
-    const Vector velocity = hit.velocity;
+    const float push = -vdotf(normal, velocity);
-    const Vector normal = hit.normal;
+    const Vector current_velocity = rigidbody_get_velocity(self);
-
+    return vaddf(current_velocity, vmulff(normal, push * rigidbody_get_bounce(self)));
-    const float elasticity = 0.0;
-    const float damping = 0.0;
-    const float push = vdotf(normal, velocity);
-
-    return ZeroVector; //vsubf(vmulff(normal, elasticity * fmaxf(1.0, -push)), vmulff(normal, damping * fminf(0.0, push)));
 }
 
 static inline
@@ -52,17 +47,10 @@ int _internal_default_contact_solver(RigidBody* body, Contact* contact, Transfor
     return 0;
 }
 
-void physics_entity_apply_collision_forces(PhysicsEntity self, List* contacts) {
-    RigidBody* body = self.tc->get_rigidbody(self.data);
-    // apply collision impulse
-    list_foreach(Contact*, contact, contacts)
-        rigidbody_add_impulse(body, _internal_calculate_contact_force(body, contact), 1);
-}
-
 void physics_entity_solve_contacts(PhysicsEntity self, List* contacts) {
-    physics_entity_apply_collision_forces(self, contacts);
     RigidBody* body = self.tc->get_rigidbody(self.data);
     const Transform pre_solve = *rigidbody_get_transform(body);
+
     // attempt to solve constraints
     int done;
     for(size_t iteration = 100; iteration != 0; --iteration) {
@@ -79,8 +67,10 @@ void physics_entity_solve_contacts(PhysicsEntity self, List* contacts) {
     Vector dir = vnormalizedf(vsubf(rigidbody_get_transform(body)->position, pre_solve.position));
     Vector vel = rigidbody_get_velocity(body);
     float dot = vdotf(dir, vel);
+
     if(dot < 0)
-        vel = vsubf(vel, vmulff(dir, dot));
+        vel = vsubf(vel, vmulff(dir, dot * (1.0 + rigidbody_get_bounce(body))));
+
     rigidbody_set_velocity(body, vel);
 }
 

src/rigidbody.c

@@ -10,6 +10,8 @@ struct RigidBody {
 
     float mass;
 
+    float bounce;
+
     Vector last_linear_force;
     Vector next_linear_force;
     Vector linear_velocity;
@@ -26,6 +28,7 @@ RigidBody* rigidbody_make(Transformable transform) {
     *self = (RigidBody){
         .transformable = transform,
         .mass = 1.0f,
+        .bounce = 0.0f,
 
         .linear_velocity = ZeroVector,
         .next_linear_force = ZeroVector,
@@ -107,6 +110,14 @@ void rigidbody_set_mass(RigidBody* self, float mass) {
     self->mass = mass;
 }
 
+float rigidbody_get_bounce(const RigidBody* self) {
+    return self->bounce;
+}
+
+void rigidbody_set_bounce(RigidBody* self, float bounce) {
+    self->bounce = bounce;
+}
+
 void rigidbody_add_impulse(RigidBody* self, Vector force, int use_mass) {
     rigidbody_accelerate(self, vmulff(force, 1.0f/delta_time()), use_mass);
 }

src/rigidbody.h

@@ -27,6 +27,9 @@ extern void rigidbody_integrate_forces(RigidBody* self);
 extern float rigidbody_get_mass(const RigidBody* self);
 extern void rigidbody_set_mass(RigidBody* self, float mass);
 
+extern float rigidbody_get_bounce(const RigidBody* self);
+extern void rigidbody_set_bounce(RigidBody* self, float bounce);
+
 extern void rigidbody_add_impulse(RigidBody* self, Vector force, int use_mass);
 extern void rigidbody_accelerate(RigidBody* self, Vector force, int use_mass);