private const float _topEdge = 0; // Y coordinate of the top edge of the playable area
public PhysicsManager(GraphicsDevice g, General.World world)
{
World = world;
StaticObjects = new List <PhysObject>();
DynamicObjects = new List <PhysObject>();
AllPhysObjects = new List <PhysObject>();
DeletionList = new List <PhysObject>();
CollisionHandler = new CollisionHandler();
Gravity = new Vector2(0.0f, 500f);
IgnoreCollision = false;
MaximumHorizontalSpeed = 400.0f;
MaximumVerticalSpeed = 600.0f;
// Create the game world physics objects
CreateEnvironment(g);
CollisionHandler.World = World;
}
// Detect collisions (uses AABB detection)
private void CollisionDetection()
{
for (int i = DynamicObjects.Count - 1; i >= 0; i--)
{
RigidBody bodyA = DynamicObjects[i].RigidBody;
AABB physObject_A_AABB = bodyA.CollidableObject.CalculateAABB(bodyA);
for (int j = AllPhysObjects.Count - 1; j >= 0; j--)
{
if (bodyA != AllPhysObjects[j].RigidBody)
{
RigidBody bodyB = AllPhysObjects[j].RigidBody;
AABB physObject_B_AABB = bodyB.CollidableObject.CalculateAABB(bodyB);
// Check if the two objects are colliding
if (CheckIntersection_AABB(physObject_A_AABB, physObject_B_AABB))
{
CollisionData collision = new CollisionData();
collision.BodyA = DynamicObjects[i];
collision.BodyB = AllPhysObjects[j];
if (collision.BodyA is Character && collision.BodyB is Character)
{
collision.IgnoreCollision = IgnoreCollision;
}
// Vector between the centre of each body
Vector2 separator = bodyB.Position - bodyA.Position;
// The distance each axis on body A has penetrated into body B
float xSeparator = (bodyA.Width / 2 + bodyB.Width / 2) - Math.Abs(separator.X);
float ySeparator = (bodyA.Height / 2 + bodyB.Height / 2) - Math.Abs(separator.Y);
if (!bodyB.CollidableObject.IsCircle)
{
if (xSeparator > ySeparator)
{
// Body A has collided with body B from above
if (bodyA.Position.Y < bodyB.Position.Y)
{
collision.ContactNormal = new Vector2(0, -1);
collision.ContactPoint = bodyA.Position - new Vector2(0, -0.2f);
}
// Body A has collided with body B from below
else
{
collision.ContactNormal = new Vector2(0, 1);
collision.ContactPoint = bodyA.Position - new Vector2(0, 0.2f);
}
collision.BodyA.TimeSinceLastCollision = 0;
collision.BodyA.TimeSinceLastCollisionWithFloor = 0;
// If it is a dynamic object, set the counter since last collision to 0
if (bodyB.IsDynamic && !collision.BodyA.IsTarget)
{
collision.BodyB.TimeSinceLastCollision = 0;
// If it collided with the floor, set the counter since last collision with floor to 0
collision.BodyB.TimeSinceLastCollisionWithFloor = 0;
}
}
else
{
// Body A has collided with body B from the left
if (bodyA.Position.X < bodyB.Position.X)
{
collision.ContactNormal = new Vector2(-1, 0);
collision.ContactPoint = bodyA.Position - new Vector2(-0.2f, 0);
}
// Body B has collided with body B from the right
else
{
collision.ContactNormal = new Vector2(1, 0);
collision.ContactPoint = bodyA.Position - new Vector2(0.2f, 0);
}
}
}
else
{
// Normal must be the distance between the two objects, normalised
collision.ContactNormal = Vector2.Normalize(separator);
collision.ContactPoint = bodyA.Position + collision.ContactNormal;
}
CollisionHandler.AddCollision(collision);
}
}
}
}
CollisionHandler.ResolveAllCollisions();
}