/// <summary>
/// Returns the collisionvector of a corner collision calculated with a circle in the center of the collision box.
/// </summary>
/// <param name="obj1">The object colliding with the corner.</param>
/// <param name="corner">The circle for this corner.</param>
/// <returns>A Vector2 of the collision.</returns>
public static Vector2 DiagonalCollision(CollisionObject obj1, Circle corner)
{
#region variables from obj1
Vector2 speed = obj1.GetSpeedTotal();
Vector2 startPos = obj1.GetCenter();
#endregion
#region Get line from movement vector and position
Line trajectoryObj = new Line(startPos, startPos + speed);
#endregion
#region Find where line intersects circle
Vector2[] intersects = corner.Intersects(trajectoryObj);
#endregion
#region Find which one of the intersections is closer
int closestIndex = GetClosestVector(intersects, startPos);
if (closestIndex == -1)
{
return(Vector2.Zero);
}
Vector2 closest = intersects[closestIndex];
#endregion
#region Define startpoint of vector
Vector2 startPoint = closest - speed;
#endregion
#region Construct a line through the intersection found earlier and the center of the circle
Line middlePointThroughIntersect = new Line(closest, corner.center);
#endregion
#region Construct a line perpandicular to this line through the startpoint
Line PerpendicularLineThroughStart = new Line(new Vector2(middlePointThroughIntersect.twoPointFormY, -middlePointThroughIntersect.twoPointFormX), startPoint);
#endregion
#region Find the intersection of the perpandicular with the line through the center of the circle
Vector2 intersectPerp = PerpendicularLineThroughStart.Intersects(middlePointThroughIntersect);
#endregion
#region Find vector from startposition to intersect of perpandicular and center line
Vector2 diffStartIntersect = intersectPerp - startPoint;
#endregion
#region Add vector to the intersection to find the reflected point
Vector2 endPoint = intersectPerp + diffStartIntersect;
#endregion
#region Return vector from intersect of incoming vector's intersect with circle to reflected point
return(-(endPoint - closest) - speed);
#endregion
//Illustration in documentation
}
/// <summary>
/// Calculates the collision vector between 2 CollisionObjects as seen from refObj, given a certain collision direction.
/// </summary>
/// <param name="refObj">The object which collides with the other.</param>
/// <param name="collObj">The object with which the first collides.</param>
/// <param name="collisionDir">The directionality of the collision.</param>
/// <returns>A vector representing the normal force collObj enacts on refObj.</returns>
public static Vector2 CollisionForce(CollisionObject refObj, CollisionObject collObj, Vector2 collisionDir)
{
#region creation variables
Vector2 collisionVector = Vector2.Zero;
Rectangle refBox = refObj.GetCollisionBox();
Rectangle collBox = collObj.GetCollisionBox();
float smallestWidth;
float smallestHeight;
if (refBox.Width < collBox.Width)
{
smallestWidth = refBox.Width;
}
else
{
smallestWidth = collBox.Width;
}
if (refBox.Height < collBox.Height)
{
smallestHeight = refBox.Height;
}
else
{
smallestHeight = collBox.Height;
}
#endregion
#region collision
switch (collisionDir.ToString())
{
#region vertical
case "{X:0 Y:-1}":
if (refObj.GetSpeedTotal().Y > 0)
{
collisionVector.Y -= refObj.GetSpeedTotal().Y *(1 + (collObj.GetBounciness() / 10) + Math.Abs(refBox.Bottom - collBox.Top) / smallestHeight);
}
break;
case "{X:0 Y:1}":
if (refObj.GetSpeedTotal().Y < 0)
{
collisionVector.Y -= refObj.GetSpeedTotal().Y *(1 + (collObj.GetBounciness() / 10) + Math.Abs(collBox.Bottom - refBox.Top) / smallestHeight);
}
break;
#endregion
#region horizontal
case "{X:-1 Y:0}":
if (refObj.GetSpeedTotal().X > 0 && (refBox.Center.Y + (refBox.Height * 0.9f) / 2 > collBox.Top || refBox.Center.Y - (refBox.Height * 0.9f) / 2 < collBox.Bottom))
{
collisionVector.X -= refObj.GetSpeedTotal().X *(1 + (collObj.GetBounciness() / 10) + Math.Abs(collBox.Left - refBox.Right) / (smallestWidth));
}
if (Globals.input.ActionsPressed().Contains(Input.Action.Right))
{
collisionVector.X -= 0.1f;
}
break;
case "{X:1 Y:0}":
if (refObj.GetSpeedTotal().X < 0 && (refBox.Center.Y + (refBox.Height * 0.9f) / 2 > collBox.Top || refBox.Center.Y - (refBox.Height * 0.9f) / 2 < collBox.Bottom))
{
collisionVector.X -= refObj.GetSpeedTotal().X *(1 + (collObj.GetBounciness() / 10) + Math.Abs(refBox.Left - collBox.Right) / (smallestWidth));
}
if (Globals.input.ActionsPressed().Contains(Input.Action.Left))
{
collisionVector.X += 0.1f;
}
break;
#endregion
#region diagonal
case "{X:-1 Y:-1}":
case "{X:-1 Y:1}":
case "{X:1 Y:-1}":
case "{X:1 Y:1}":
Vector2 center = new Vector2(collBox.Center.X, collBox.Center.Y);
collisionVector += DiagonalCollision(refObj, new Circle(center, Vector2.Distance(center, new Vector2(collBox.X, collBox.Y)))) * PhysicsConstants.metersPerPixel;
break;
#endregion
}
if (Math.Sign(collObj.GetSpeedTotal().X) != Math.Sign(refObj.GetSpeedTotal().X))
{
collisionVector += collObj.GetSpeed() * refObj.CollisionImpactMultiplier();
}
#endregion
return(collisionVector);
}
