/// <summary>
/// Get the position so that the object does not collide with the object anymore.
/// Important: this is used raycasting checks, as this needs some more corner-cases.
/// </summary>
/// <param name="collider">The collider which is the player</param>
/// <param name="collisionPoint">Point of the collision in the scene</param>
/// <param name="hitNormal">Collision-normal of the object with which the player collided</param>
/// <returns>Position which is possible for the collider so there is no collision.</returns>
private JVector GetPosition(Collider collider, JVector collisionPoint, JVector hitNormal)
{
JVector bbSize = collider.BoundingBoxSize;
GameObject gameObject = collider.GameObject;
// Calculate the size of the forward and right vector based on the bounding-box.
JVector forward = 0.5f * bbSize.Z * Conversion.ToJitterVector(gameObject.transform.Forward);
JVector right = 0.5f * bbSize.X * Conversion.ToJitterVector(gameObject.transform.Right);
JVector d = Conversion.ToJitterVector(gameObject.transform.Forward);
if (hitNormal.IsZero())
{
return(bbSize.Z * -0.5f * Conversion.ToJitterVector(gameObject.transform.Forward));
}
// Correct directions
TurnIntoDirectionOf(ref forward, hitNormal);
TurnIntoDirectionOf(ref right, hitNormal);
TurnIntoDirectionOf(ref d, hitNormal);
// Calculate the projected length (half-length) of the player on the hit-normal.
JVector lengthOnNormal = ProjectOn(forward, hitNormal);
JVector widthOnNormal = ProjectOn(right, hitNormal);
JVector projectedSize = lengthOnNormal + widthOnNormal;
JVector margin = ProjectOn(projectedSize, d);
JVector endPosition = collisionPoint + margin;
// Check if it hit a corner and it could actually go closer
JVector plane = new JVector(-hitNormal.Z, 0, hitNormal.X);
TurnIntoDirectionOf(ref plane, -1 * forward);
plane.Normalize();
// Check if there is an intersection between the front-"plane" of the player and the collided object
JVector intersection;
JVector frontMiddle = endPosition + forward;
JVector frontRight = endPosition + forward - right;
JVector planeEnd = collisionPoint + MathHelper.Max(bbSize.X, bbSize.Z) * plane;
if (DoIntersect(frontMiddle, frontRight, collisionPoint, planeEnd, out intersection))
{
intersection.Y = collider.Position.Y;
JVector colToIntersection = intersection - collisionPoint;
JVector margin2 = ProjectOn(colToIntersection, d);
margin = margin.LengthSquared() > margin2.LengthSquared() ? margin2 : margin;
endPosition = collisionPoint + margin;
}
//// Todo: Visual debuggin might be removed in the end
//PhysicsDrawer.Instance.ClearPointsToDraw();
//PhysicsDrawer.Instance.AddPointToDraw(Conversion.ToXnaVector(collisionPoint));
//PhysicsDrawer.Instance.AddPointToDraw(Conversion.ToXnaVector(endPosition));
//return collider.Position;
return(endPosition);
}
/// <summary>
/// Get the position so that the object does not collide with the object anymore.
/// Important: this is used for the normal collision-handling.
/// </summary>
/// <param name="collider">The collider which is the player</param>
/// <param name="collisionPoint">Point of the collision in the scene</param>
/// <param name="hitNormal">Collision-normal of the object with which the player collided</param>
/// <returns>Position which is possible for the collider so there is no collision.</returns>
private JVector ProjectToNonCollision(Collider collider, JVector collisionPoint, JVector hitNormal)
{
JVector bbSize = collider.BoundingBoxSize;
GameObject gameObject = collider.GameObject;
// This should actually not happen
if (hitNormal.IsZero())
{
return(bbSize.Z * -0.5f * Conversion.ToJitterVector(gameObject.transform.Forward));
}
// Calculate the size of the forward and right vector based on the bounding-box.
JVector forward = 0.5f * bbSize.Z * Conversion.ToJitterVector(gameObject.transform.Forward);
JVector right = 0.5f * bbSize.X * Conversion.ToJitterVector(gameObject.transform.Right);
// Correct directions for calculations.
TurnIntoDirectionOf(ref forward, hitNormal);
TurnIntoDirectionOf(ref right, hitNormal);
// Calculate the projected length (half-length) of the player on the hit-normal.
JVector lengthOnNormal = ProjectOn(forward, hitNormal);
JVector widthOnNormal = ProjectOn(right, hitNormal);
JVector projectedSize = lengthOnNormal + widthOnNormal;
// Get vector which gives the non-collided-part of the car projected on the hit-normal.
JVector distColToPos = collisionPoint - collider.Position;
// Correct directions for calculations.
TurnIntoDirectionOf(ref projectedSize, hitNormal);
TurnIntoDirectionOf(ref distColToPos, hitNormal);
// Calculate the penetration-depth of the collision
JVector nonCollidedSize = ProjectOn(distColToPos, hitNormal);
JVector penetration = nonCollidedSize - projectedSize;
// Todo: Visual debuggin might be removed in the end
PhysicsDrawer.Instance.AddPointToDraw(Conversion.ToXnaVector(collider.Position - (1 + Epsilon) * penetration));
// Calcualte the position for the player so it doesn't collide anymore
return(collider.Position - (1 + Epsilon) * penetration);
}