//Checks if 2 colliders are intersecting and will run resolve if they are
public void DetectCollision(Rigid_Body body1, Rigid_Body body2)
{
//1st collider in detection
Base_Collider col1 = body1.Collider;
//2nd collider in detection
Base_Collider col2 = body2.Collider;
CollisionInfo collision = new CollisionInfo();
//Check what type of collision check needs to happen
if (col1.Collider_Type == ColliderType.AABB && col2.Collider_Type == ColliderType.AABB)
{
collision = AABBvsAABB((AABB_Collider)col1, (AABB_Collider)col2);
}
else if (col1.Collider_Type == ColliderType.CIRCLE && col2.Collider_Type == ColliderType.CIRCLE)
{
collision = CIRCLEvsCIRCLE((Circle_Collider)col1, (Circle_Collider)col2);
}
else if (col1.Collider_Type == ColliderType.CIRCLE && col2.Collider_Type == ColliderType.AABB)
{
collision = CIRCLEvsAABB((Circle_Collider)col1, (AABB_Collider)col2, false);
}
else if (col1.Collider_Type == ColliderType.AABB && col2.Collider_Type == ColliderType.CIRCLE)
{
collision = CIRCLEvsAABB((Circle_Collider)col2, (AABB_Collider)col1, true);
}
if (collision.hit)
{
ResolveCollision(collision, body1, body2);
}
}
//Creates an explosion force in world at position of body
public void CreateExplosion(float explosionForce, Rigid_Body source)
{
Vec2 force = Vec2.Zero;
Vec2 acceleration = Vec2.Zero;
Vec2 direction = Vec2.Zero;
//Debug.Log(dynamicBodies.Count);
for (int i = 0; i < dynamicBodies.Count; i++)
{
//Debug.Log(dynamicBodies[i].gameObject.name);
//Debug.Log(source.gameObject.name);
if (dynamicBodies[i].gameObject.name != source.gameObject.name)
{
direction = dynamicBodies[i].Position - source.Position;
if (direction.Magnitude() < explosionForce)
{
force = explosionForce * direction.Normalized * ((explosionForce - direction.Magnitude()) / explosionForce);
dynamicBodies[i].ApplyForceInstant(force);
}
}
}
}
public CollisionPair(Rigid_Body a, Rigid_Body b)
{
A = a;
B = b;
}
//This function handles the separating of collider, Resolution handles restitution, friction and positional correction
public void ResolveCollision(CollisionInfo collisionInfo, Rigid_Body _collider, Rigid_Body _collided)
{
if (!_collider.Collider.Trigger && !_collided.Collider.Trigger)
{
//impulse resolution, applies velocity to both rigid bodies involved in collision and positional correction is done for resting objects to stop
//colliders sinking in to eachother. Mass is taken in to account any time velocity is changed.
float invMassCollider = 0;
float invMassCollided = 0;
if (_collider.Mass != 0)
{
invMassCollider = 1 / _collider.Mass;
}
if (_collided.Mass != 0)
{
invMassCollided = 1 / _collided.Mass;
}
// Calculate relative velocity
Vec2 rv = _collided.velocity - _collider.velocity;
// Calculate relative velocity in terms of the normal direction
float velAlongNormal = rv.DotProduct(collisionInfo.collisionNormal);
// Do not resolve if velocities are separating
if (velAlongNormal > 0)
{
return;
}
// Calculate restitution
float e = Mathf.Min(_collider.Collider.P_Mat.restitution, _collided.Collider.P_Mat.restitution);
// Calculate impulse scalar
float j = -(1 + e) * velAlongNormal;
j /= invMassCollider + invMassCollided;
// Apply impulse
Vec2 impulse = j * collisionInfo.collisionNormal;
_collider.velocity -= invMassCollider * impulse;
_collided.velocity += invMassCollided * impulse;
// Re-calculate relative velocity after normal impulse is applied
Vec2 impulseVel = _collided.velocity - _collider.velocity;
// Solve for the tangent vector
Vec2 tangent = impulseVel - impulseVel.DotProduct(collisionInfo.collisionNormal) * collisionInfo.collisionNormal;
tangent.Normalize();
// Solve for magnitude to apply along the friction vector
float jt = -impulseVel.DotProduct(tangent);
jt = jt / (invMassCollider + invMassCollided);
//Get coefficient based on Material attached to colliders
float mu = Physics_Material.CombineFrictions(_collider.Collider.P_Mat.staticFriction,
_collided.Collider.P_Mat.staticFriction,
_collider.Collider.P_Mat.frictionCombine);
// Clamp magnitude of friction and create impulse vector
Vec2 frictionImpulse;
if (Mathf.Abs(jt) < j * mu)
{
frictionImpulse = jt * tangent;
}
else
{
frictionImpulse = -j *tangent *Physics_Material.CombineFrictions(_collider.Collider.P_Mat.dynamicFriction,
_collided.Collider.P_Mat.dynamicFriction,
_collider.Collider.P_Mat.frictionCombine);
}
// Apply friction impulse
_collider.velocity -= invMassCollider * frictionImpulse;
_collided.velocity += invMassCollided * frictionImpulse;
//Correct for float precision error so object does not sink in to resting colliders
const float percent = 0.8f; // usually 20% to 80%
Vec2 correction = Vec2.Zero;
correction.x = (Mathf.Abs(collisionInfo.depth.x) / (invMassCollider + invMassCollided)) * percent * collisionInfo.collisionNormal.x;
correction.y = (Mathf.Abs(collisionInfo.depth.y) / (invMassCollider + invMassCollided)) * percent * collisionInfo.collisionNormal.y;
//Debug.Log("correction: " + _collider.gameObject.name + " " + correction.x + " " + correction.y);
_collider.Position -= invMassCollider * correction;
_collided.Position += invMassCollided * correction;
}
//Trigger on collision enter delegate. Default is an empty function
_collider.Collider.CollisionEnter(_collided.Collider, collisionInfo);
collisionInfo.collisionNormal *= -1f;
_collided.Collider.CollisionEnter(_collider.Collider, collisionInfo);
}
