/// <summary>
/// If objects are moving toward each other in x direction, returns weighted average of x velocities and original y velocities.
/// <para>Repeats logic in y direction.</para>
/// </summary>
public static VelocityPair CollideSlide(BoxCollider left, BoxCollider right, Vector2 leftVel, Vector2 rightVel, float horzLeftWeight = 0.5f, float vertLeftWeight = 0.5f)
{
if (PhysicsMath.GetNormal(left, right).X != 0)
{
// Horizontal collision
if (IsMovingTowardEachOther(left.Position.X, right.Position.X, leftVel.X, rightVel.X))
{
// Objects are moving toward each other in x direction, return weighted average of x velocities.
float xAvg = WeightedAverage(leftVel.X, rightVel.X, horzLeftWeight);
return(new VelocityPair(new Vector2(xAvg, leftVel.Y), new Vector2(xAvg, rightVel.Y)));
}
else
{
// Objects are moving apart, return original velocities.
return(new VelocityPair(leftVel, rightVel));
}
}
else
{
// Vertical collision
if (IsMovingTowardEachOther(left.Position.Y, right.Position.Y, leftVel.Y, rightVel.Y))
{
// Objects are moving toward each other in y direction, return weighted average of y velocities.
float yAvg = WeightedAverage(leftVel.Y, rightVel.Y, vertLeftWeight);
return(new VelocityPair(new Vector2(leftVel.X, yAvg), new Vector2(rightVel.X, yAvg)));
}
else
{
// Objects are moving apart, return original velocities.
return(new VelocityPair(leftVel, rightVel));
}
}
}
/// <summary>
/// Collides the given actor against all other rigidbodies and calculate the allowed velocity during this frame.
/// </summary>
/// <remarks>This function will immediately return if the calculated velocity becomes zero.</remarks>
private static void CalculateActorVelocity(ActorRigidbody actor)
{
actor.ProcessingData.CalcVel = actor.Velocity;
if (actor.Velocity == Vector2.Zero)
{
return;
}
foreach (var staticbody in AllStatics)
{
if (actor.ProcessingData.CalcVel == Vector2.Zero)
{
return;
}
if (PhysicsMath.IsOverlapping(actor.MainCollider, staticbody.MainCollider))
{
if (!PhysicsMath.IsSlidingCorner(actor.MainCollider, staticbody.MainCollider))
{
actor.ProcessingData.CalcVel = VelocityMath.IntoPlane(actor.ProcessingData.CalcVel, PhysicsMath.GetNormal(actor.MainCollider, staticbody.MainCollider));
}
}
}
foreach (var solid in AllSolids)
{
foreach (var solidCollider in solid.Colliders)
{
if (actor.ProcessingData.CalcVel == Vector2.Zero)
{
return;
}
if (PhysicsMath.IsOverlapping(actor.MainCollider, solidCollider))
{
if (!PhysicsMath.IsSlidingCorner(actor.MainCollider, solidCollider))
{
actor.ProcessingData.CalcVel = VelocityMath.IntoPlane(actor.ProcessingData.CalcVel, PhysicsMath.GetNormal(actor.MainCollider, solidCollider));
}
}
}
}
}
private static void CalculateSolidVelocity(SolidRigidbody solid)
{
solid.ProcessingData.CalcVel = solid.Velocity;
if (solid.Velocity == Vector2.Zero)
{
return; // Early exit if no velocity.
}
// Regional check against all static rigidbodies
foreach (var staticbody in AllStatics)
{
foreach (var collider in solid.Colliders)
{
if (solid.ProcessingData.CalcVel == Vector2.Zero)
{
return;
}
if (PhysicsMath.IsOverlapping(collider, staticbody.MainCollider))
{
if (!PhysicsMath.IsSlidingCorner(collider, staticbody.MainCollider))
{
solid.ProcessingData.CalcVel = VelocityMath.IntoPlane(solid.ProcessingData.CalcVel, PhysicsMath.GetNormal(collider, staticbody.MainCollider));
Console.WriteLine($"Solid collision against {staticbody.Entity} ({collider.LocalPosition}) to yield {solid.ProcessingData.CalcVel}");
}
}
}
}
// Regional check against other solids
foreach (var otherSolid in AllSolids)
{
if (solid.ProcessingData.CalcVel == Vector2.Zero)
{
return;
}
// Skip self
if (ReferenceEquals(solid, otherSolid))
{
continue;
}
// Skip if other solid has already processed this solid
if (otherSolid.ProcessingData.CheckedAgainst.Contains(solid))
{
continue;
}
if (PhysicsMath.IsOverlapping(solid.MainCollider, otherSolid.MainCollider))
{
if (!PhysicsMath.IsSlidingCorner(solid.MainCollider, otherSolid.MainCollider))
{
VelocityPair result = Ruleset.Get(solid, otherSolid);
Console.WriteLine($"Collided {solid.Entity} against {otherSolid.Entity} to yield {result.left} and {result.right}");
solid.ProcessingData.CalcVel = result.left;
otherSolid.ProcessingData.CalcVel = result.right;
solid.ProcessingData.CheckedAgainst.Add(otherSolid);
otherSolid.ProcessingData.CheckedAgainst.Add(solid);
}
}
}
}