/// <summary>
/// Add a new CollisionUnit to the CollisionChief.
/// </summary>
/// <param name="unit">The CollisionUnit to add to the CollisionChief.</param>
public void AddCollisionUnit(CollisionUnit unit)
{
Vector2 circleCenter;
int circleRadius;
Vector2 lineStart;
Vector2 lineEnd;
Point topLeftCell;
Point bottomRightCell;
if (unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_CIRCLE)
{
circleCenter = unit.GetCircleCenter();
circleRadius = unit.GetCircleRadius();
// put in appropriate cells
topLeftCell = CalculateCircleTopLeftCell(circleCenter, circleRadius);
bottomRightCell = CalculateCircleBottomRightCell(circleCenter, circleRadius);
for (int i = topLeftCell.X; i <= bottomRightCell.X; i++)
{
for (int j = topLeftCell.Y; j <= bottomRightCell.Y; j++)
{
mCollisionGrid.Cells[i,j].AddCollisionUnit(unit);
}
}
}
else if (unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_LINE)
{
lineStart = unit.GetLineStart();
lineEnd = unit.GetLineEnd();
// TODO: put in appropriate cells
}
else if (unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_BOX)
{
topLeftCell = CalculateCellPosition(unit.GetUpperLeft());
bottomRightCell = CalculateCellPosition(unit.GetLowerRight());
for (int i = topLeftCell.X; i <= bottomRightCell.X; i++)
{
for (int j = topLeftCell.Y; j <= bottomRightCell.Y; j++)
{
mCollisionGrid.Cells[i, j].AddCollisionUnit(unit);
}
}
}
}
/// <summary>
/// Get the point of collision with the <paramref name="other"/> CollisionUnit. This does not do any real collision checks so the returned value might not be the actual collision point.
/// </summary>
/// <param name="other">The CollisionUnit to get the collision point from.</param>
/// <returns>A Vector2 representing the collision point.</returns>
public Vector2 GetCollisionPoint(CollisionUnit other)
{
Vector2 otherCircleCenter;
int otherCircleRadius;
Vector2 boxUpperLeft;
Vector2 boxLowerRight;
float dX;
float dY;
float ratio;
Vector2 collisionPoint = new Vector2(-1, -1);
if (mCollisionType == CollisionType.COLLISION_CIRCLE && other.GetCollisionType() == CollisionType.COLLISION_CIRCLE)
{
otherCircleCenter = other.GetCircleCenter();
otherCircleRadius = other.GetCircleRadius();
dX = otherCircleCenter.X - mCircleCenter.X;
dY = otherCircleCenter.Y - mCircleCenter.Y;
ratio = ((float)mCircleRadius) / (mCircleRadius + otherCircleRadius);
dX *= ratio;
dY *= ratio;
collisionPoint = new Vector2(mCircleCenter.X + dX, mCircleCenter.Y + dY);
}
else if ((mCollisionType == CollisionType.COLLISION_CIRCLE && other.GetCollisionType() == CollisionType.COLLISION_BOX)
|| (mCollisionType == CollisionType.COLLISION_BOX && other.GetCollisionType() == CollisionType.COLLISION_CIRCLE))
{
if (mCollisionType == CollisionType.COLLISION_CIRCLE)
{
otherCircleCenter = mCircleCenter;
otherCircleRadius = mCircleRadius;
boxUpperLeft = other.GetUpperLeft();
boxLowerRight = other.GetLowerRight();
}
else
{
otherCircleCenter = other.GetCircleCenter();
otherCircleRadius = other.GetCircleRadius();
boxUpperLeft = mPoint1;
boxLowerRight = mPoint2;
}
if (otherCircleCenter.X > boxLowerRight.X)
{
if (otherCircleCenter.Y > boxLowerRight.Y)
{
collisionPoint = boxLowerRight;
}
else if (otherCircleCenter.Y < boxUpperLeft.Y)
{
collisionPoint = new Vector2(boxLowerRight.X, boxUpperLeft.Y);
}
else
{
collisionPoint = new Vector2(otherCircleCenter.X - otherCircleRadius, otherCircleCenter.Y);
}
}
else if (otherCircleCenter.X < boxUpperLeft.X)
{
if (otherCircleCenter.Y > boxLowerRight.Y)
{
collisionPoint = new Vector2(boxUpperLeft.X, boxLowerRight.Y);
}
else if (otherCircleCenter.Y < boxUpperLeft.Y)
{
collisionPoint = boxUpperLeft;
}
else
{
collisionPoint = new Vector2(otherCircleCenter.X + otherCircleRadius, otherCircleCenter.Y);
}
}
else if (otherCircleCenter.Y > boxLowerRight.Y)
{
collisionPoint = new Vector2(otherCircleCenter.X, otherCircleCenter.Y - otherCircleRadius);
}
else if (otherCircleCenter.Y < boxUpperLeft.Y)
{
collisionPoint = new Vector2(otherCircleCenter.X, otherCircleCenter.Y + otherCircleRadius);
}
else
{
// inside
collisionPoint = otherCircleCenter;
}
}
return collisionPoint;
}
/// <summary>
/// Determine if this CollisionUnit collides with another.
/// </summary>
/// <param name="other">The CollisionUnit to check for collision.</param>
/// <returns><code>true</code> if this collision unit collides with the <paramref name="other"/> CollisionUnit, <code>false</code> if otherwise.</returns>
public bool CollidesWith(CollisionUnit other)
{
Vector2 otherCircleCenter;
int otherCircleRadius;
float dX;
float dY;
float dist;
Vector2 otherUpperLeft;
Vector2 otherLowerRight;
mCheckedUnits.Add(other);
if (mCollisionType == CollisionType.COLLISION_CIRCLE && other.GetCollisionType() == CollisionType.COLLISION_CIRCLE)
{
otherCircleCenter = other.GetCircleCenter();
otherCircleRadius = other.GetCircleRadius();
dX = mCircleCenter.X - otherCircleCenter.X;
dY = mCircleCenter.Y - otherCircleCenter.Y;
dist = (dX * dX) + (dY * dY);
// (radius + radius)^2 instead of more expensive squareRoot(dist)
return (dist <= (mCircleRadius + otherCircleRadius) * (mCircleRadius + otherCircleRadius));
}
else if (mCollisionType == CollisionType.COLLISION_CIRCLE && other.GetCollisionType() == CollisionType.COLLISION_BOX)
{
return CircleBoxCollision(mCircleCenter, mCircleRadius, other.GetUpperLeft(), other.GetLowerRight());
}
else if (mCollisionType == CollisionType.COLLISION_BOX && other.GetCollisionType() == CollisionType.COLLISION_CIRCLE)
{
return CircleBoxCollision(other.GetCircleCenter(), other.GetCircleRadius(), mPoint1, mPoint2);
}
else if (mCollisionType == CollisionType.COLLISION_BOX && other.GetCollisionType() == CollisionType.COLLISION_BOX)
{
otherUpperLeft = other.GetUpperLeft();
otherLowerRight = other.GetLowerRight();
return (mPoint1.X <= otherLowerRight.X && mPoint1.Y <= otherLowerRight.Y && otherUpperLeft.X <= mPoint2.X && otherUpperLeft.Y <= mPoint2.Y);
}
// TODO: other collision types - line, pixel
return false;
}
/// <summary>
/// Add a bounce between two CollisionUnits based on the velocity.
/// </summary>
/// <param name="unit">The main collision unit involved in the "bounce".</param>
/// <param name="other">The secondary collision unit involved in the "bounce".</param>
public void AddBounce(CollisionUnit unit, CollisionUnit other)
{
Vector2 unitCircleCenter;
Vector2 otherCircleCenter;
int unitRadius;
int otherRadius;
Vector2 oldVelocity;
Vector2 norm;
Vector2 unitNorm;
Vector2 unitTan = new Vector2();
Vector2 oldVelocityOther = new Vector2(0, 0);
float velocityNorm;
float velocityTan;
float velocityNormOther;
float velocityTanOther;
float newVelocityScalar;
float newVelocityScalarOther;
Vector2 newVelocityNorm;
Vector2 newVelocityNormOther;
Vector2 newVelocityTan;
Vector2 newVelocityTanOther;
Vector2 newVelocity;
Vector2 newVelocityOther;
float mass = 1;
float massOther = 10000;
Vector2 velocityDiff;
if (unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_CIRCLE && other.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_CIRCLE)
{
unitCircleCenter = unit.GetCircleCenter();
unitRadius = unit.GetCircleRadius();
otherCircleCenter = other.GetCircleCenter();
otherRadius = other.GetCircleRadius();
oldVelocity = mVelocity;
////////////////
norm = otherCircleCenter - unitCircleCenter;
unitNorm = norm / ((float)Math.Sqrt(norm.X * norm.X + norm.Y * norm.Y));
unitTan.X = unitNorm.Y * -1;
unitTan.Y = unitNorm.X;
velocityNorm = Vector2.Dot(unitNorm, oldVelocity);
velocityTan = Vector2.Dot(unitTan, oldVelocity);
velocityNormOther = Vector2.Dot(unitNorm, oldVelocityOther);
velocityTanOther = Vector2.Dot(unitTan, oldVelocityOther);
newVelocityScalar = (velocityNorm * (mass - massOther) + 2 * massOther * velocityNormOther) / (mass + massOther);
newVelocityScalarOther = (velocityNormOther * (massOther - mass) + 2 * mass * velocityNorm) / (mass + massOther);
newVelocityNorm = newVelocityScalar * unitNorm;
newVelocityNormOther = newVelocityScalarOther * unitNorm;
newVelocityTan = velocityTan * unitTan;
newVelocityTanOther = velocityTanOther * unitTan;
newVelocity = newVelocityNorm + newVelocityTan;
newVelocityOther = newVelocityNormOther + newVelocityTanOther;
newVelocity *= 0.99f;
velocityDiff = newVelocity - mVelocity;
mVelocity = newVelocity;
// some fudge
//if (velocityDiff.X > 1 || velocityDiff.X < -1 || velocityDiff.Y > 1 || velocityDiff.Y < -1)
//{
mOwner.Translate(0.04f * (unitCircleCenter.X - otherCircleCenter.X), 0.04f * (unitCircleCenter.Y - otherCircleCenter.Y));
//}
}
else
{
newVelocity = mVelocity * -0.8f;
velocityDiff = newVelocity - mVelocity;
mVelocity = newVelocity;
unitCircleCenter = unit.GetCircleCenter();
otherCircleCenter = unit.GetCollisionPoint(other);
//if (velocityDiff.X > 1 || velocityDiff.X < -1 || velocityDiff.Y > 1 || velocityDiff.Y < -1)
//{
mOwner.Translate(0.04f * (unitCircleCenter.X - otherCircleCenter.X), 0.04f * (unitCircleCenter.Y - otherCircleCenter.Y));
//}
}
}
/// <summary>
/// Translate a CollisionUnit by the given amount.
/// </summary>
/// <param name="unit">The CollisionUnit to translate.</param>
/// <param name="translation">The delta translation to perform on the CollisionUnit.</param>
public void TranslateCollisionUnit(CollisionUnit unit, Vector2 translation)
{
int circleRadius;
Vector2 oldCircleCenter;
Vector2 oldLineStart;
Vector2 oldLineEnd;
Point oldTopLeftCell;
Point oldBottomRightCell;
Vector2 newCircleCenter;
Point newTopLeftCell;
Point newBottomRightCell;
if (unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_CIRCLE || unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_BOX)
{
if (unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_CIRCLE)
{
circleRadius = unit.GetCircleRadius();
oldCircleCenter = unit.GetCircleCenter();
newCircleCenter = oldCircleCenter + translation;
// calculate containing cells
oldTopLeftCell = CalculateCircleTopLeftCell(oldCircleCenter, circleRadius);
oldBottomRightCell = CalculateCircleBottomRightCell(oldCircleCenter, circleRadius);
newTopLeftCell = CalculateCircleTopLeftCell(newCircleCenter, circleRadius);
newBottomRightCell = CalculateCircleBottomRightCell(newCircleCenter, circleRadius);
}
else
{
oldTopLeftCell = CalculateCellPosition(unit.GetUpperLeft());
oldBottomRightCell = CalculateCellPosition(unit.GetLowerRight());
newTopLeftCell = CalculateCellPosition(unit.GetUpperLeft() + translation);
newBottomRightCell = CalculateCellPosition(unit.GetLowerRight() + translation);
}
// remove from cells no longer within and add to new cells that unit is within
if (translation.X > 0)
{
// remove
for (int i = oldTopLeftCell.X; i < newTopLeftCell.X && i <= oldBottomRightCell.X; i++)
{
for (int j = oldTopLeftCell.Y; j <= oldBottomRightCell.Y; j++)
{
mCollisionGrid.Cells[i, j].RemoveCollisionUnit(unit);
}
}
// add
int minStart = oldBottomRightCell.X + 1;
if (minStart < newTopLeftCell.X)
{
minStart = newTopLeftCell.X;
}
for (int i = minStart; i <= newBottomRightCell.X; i++)
{
for (int j = newTopLeftCell.Y; j <= newBottomRightCell.Y; j++)
{
mCollisionGrid.Cells[i, j].AddCollisionUnit(unit);
}
}
}
else if (translation.X < 0)
{
// remove
int minStart = newBottomRightCell.X + 1;
if (minStart < oldTopLeftCell.X)
{
minStart = oldTopLeftCell.X;
}
for (int i = minStart; i <= oldBottomRightCell.X; i++)
{
for (int j = oldTopLeftCell.Y; j <= oldBottomRightCell.Y; j++)
{
mCollisionGrid.Cells[i, j].RemoveCollisionUnit(unit);
}
}
// add
for (int i = newTopLeftCell.X; i < oldTopLeftCell.X && i <= newBottomRightCell.X; i++)
{
for (int j = newTopLeftCell.Y; j <= newBottomRightCell.Y; j++)
{
mCollisionGrid.Cells[i, j].AddCollisionUnit(unit);
}
}
}
if (translation.Y > 0)
{
// remove
for (int i = oldTopLeftCell.Y; i < newTopLeftCell.Y && i <= oldBottomRightCell.Y; i++)
{
for (int j = oldTopLeftCell.X; j <= oldBottomRightCell.X; j++)
{
mCollisionGrid.Cells[j, i].RemoveCollisionUnit(unit);
}
}
// add
int minStart = oldBottomRightCell.Y + 1;
if (minStart < newTopLeftCell.Y)
{
minStart = newTopLeftCell.Y;
}
for (int i = minStart; i <= newBottomRightCell.Y; i++)
{
// avoid double adds
if (translation.X > 0)
{
for (int j = newTopLeftCell.X; j <= oldBottomRightCell.X; j++)
{
mCollisionGrid.Cells[j, i].AddCollisionUnit(unit);
}
}
else
{
for (int j = oldTopLeftCell.X; j <= newBottomRightCell.X; j++)
{
mCollisionGrid.Cells[j, i].AddCollisionUnit(unit);
}
}
}
}
else if (translation.Y < 0)
{
// remove
int minStart = newBottomRightCell.Y + 1;
if (minStart < oldTopLeftCell.Y)
{
minStart = oldTopLeftCell.Y;
}
for (int i = minStart; i <= oldBottomRightCell.Y; i++)
{
for (int j = oldTopLeftCell.X; j <= oldBottomRightCell.X; j++)
{
mCollisionGrid.Cells[j, i].RemoveCollisionUnit(unit);
}
}
// add
for (int i = newTopLeftCell.Y; i < oldTopLeftCell.Y && i <= newBottomRightCell.Y; i++)
{
// avoid double adds
if (translation.X > 0)
{
for (int j = newTopLeftCell.X; j <= oldBottomRightCell.X; j++)
{
mCollisionGrid.Cells[j, i].AddCollisionUnit(unit);
}
}
else
{
for (int j = oldTopLeftCell.X; j <= newBottomRightCell.X; j++)
{
mCollisionGrid.Cells[j, i].AddCollisionUnit(unit);
}
}
}
}
}
else if (unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_LINE)
{
oldLineStart = unit.GetLineStart();
oldLineEnd = unit.GetLineEnd();
// TODO: put in appropriate cells
}
}
/// <summary>
/// Scale a CollisionUnit by the given amount.
/// </summary>
/// <param name="unit">The CollisionUnit to scale.</param>
/// <param name="scale">The delta scale to perform on the CollisionUnit.</param>
public void ScaleCollisionUnit(CollisionUnit unit, Vector2 scale)
{
int oldCircleRadius;
int newCircleRadius;
Vector2 circleCenter;
Vector2 oldLineStart;
Vector2 oldLineEnd;
Point oldTopLeftCell;
Point oldBottomRightCell;
Point newTopLeftCell;
Point newBottomRightCell;
bool scaleFromCenter = false;
if (unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_CIRCLE || unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_BOX)
{
if (unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_CIRCLE)
{
oldCircleRadius = unit.GetCircleRadius();
//newCircleRadius = (int)(unit.GetCircleRadius() * ((scale.X + scale.Y) / 2));
//newCircleRadius = (int)(unit.GetCircleRadius() + unit.GetCircleRadius() * ((scale.X + scale.Y) / 2));
newCircleRadius = (int)(unit.GetCircleRadius() + ((scale.X + scale.Y) / 2));
circleCenter = unit.GetCircleCenter();
// calculate containing cells
oldTopLeftCell = CalculateCircleTopLeftCell(circleCenter, oldCircleRadius);
oldBottomRightCell = CalculateCircleBottomRightCell(circleCenter, oldCircleRadius);
newTopLeftCell = CalculateCircleTopLeftCell(circleCenter, newCircleRadius);
newBottomRightCell = CalculateCircleBottomRightCell(circleCenter, newCircleRadius);
}
else
{
Vector2 point1 = unit.GetUpperLeft();
Vector2 point2 = unit.GetLowerRight();
int oldWidth = unit.GetWidth();
int oldHeight = unit.GetHeight();
//int xChange = (int)(((oldWidth * scale.X) - oldWidth) / 2);
//int yChange = (int)(((oldHeight * scale.Y) - oldHeight) / 2);
//int xChange = (int)(oldWidth * scale.X / 2);
//int yChange = (int)(oldHeight * scale.Y / 2);
int xChange = (int)scale.X;
int yChange = (int)scale.Y;
// scale from center
if (scaleFromCenter)
{
point1.X -= xChange;
point1.Y -= yChange;
point2.X += xChange;
point2.Y += yChange;
}
else
{
// scale with top left stationary
point2.X += xChange * 2;
point2.Y += yChange * 2;
}
oldTopLeftCell = CalculateCellPosition(unit.GetUpperLeft());
oldBottomRightCell = CalculateCellPosition(unit.GetLowerRight());
newTopLeftCell = CalculateCellPosition(point1);
newBottomRightCell = CalculateCellPosition(point2);
}
//if (scale.X < 1)
if (scale.X < 0)
{
for (int j = oldTopLeftCell.Y; j <= oldBottomRightCell.Y; j++)
{
// remove left
for (int i = oldTopLeftCell.X; i < newTopLeftCell.X; i++)
{
mCollisionGrid.Cells[i, j].RemoveCollisionUnit(unit);
}
// remove right
for (int i = newBottomRightCell.X + 1; i <= oldBottomRightCell.X; i++)
{
mCollisionGrid.Cells[i, j].RemoveCollisionUnit(unit);
}
}
//if (scale.Y < 1)
if (scale.Y < 0)
{
for (int i = newTopLeftCell.X; i <= newBottomRightCell.X; i++)
{
// remove top
for (int j = oldTopLeftCell.Y; j < newTopLeftCell.Y; j++)
{
mCollisionGrid.Cells[i, j].RemoveCollisionUnit(unit);
}
// remove bottom
for (int j = newBottomRightCell.Y + 1; j <= oldBottomRightCell.Y; j++)
{
mCollisionGrid.Cells[i, j].RemoveCollisionUnit(unit);
}
}
}
//else if (scale.Y > 1)
else if (scale.Y > 0)
{
for (int i = newTopLeftCell.X; i <= newBottomRightCell.X; i++)
{
// add top
for (int j = newTopLeftCell.Y; j < oldTopLeftCell.Y; j++)
{
mCollisionGrid.Cells[i, j].AddCollisionUnit(unit);
}
// add bottom
for (int j = oldBottomRightCell.Y + 1; j <= newBottomRightCell.Y; j++)
{
mCollisionGrid.Cells[i, j].AddCollisionUnit(unit);
}
}
}
}
//else if (scale.X > 1)
else if (scale.X > 0)
{
for (int j = newTopLeftCell.Y; j <= newBottomRightCell.Y; j++)
{
// add left
for (int i = newTopLeftCell.X; i < oldTopLeftCell.X; i++)
{
mCollisionGrid.Cells[i, j].AddCollisionUnit(unit);
}
// add right
for (int i = oldBottomRightCell.X + 1; i <= newBottomRightCell.X; i++)
{
mCollisionGrid.Cells[i, j].AddCollisionUnit(unit);
}
}
//if (scale.Y < 1)
if (scale.Y < 0)
{
for (int i = oldTopLeftCell.X; i <= oldBottomRightCell.X; i++)
{
// remove top
for (int j = oldTopLeftCell.Y; j < newTopLeftCell.Y; j++)
{
mCollisionGrid.Cells[i, j].RemoveCollisionUnit(unit);
}
// remove bottom
for (int j = newBottomRightCell.Y + 1; j <= oldBottomRightCell.Y; j++)
{
mCollisionGrid.Cells[i, j].RemoveCollisionUnit(unit);
}
}
}
//else if (scale.Y > 1)
else if (scale.Y > 0)
{
for (int i = oldTopLeftCell.X; i <= oldBottomRightCell.X; i++)
{
// add top
for (int j = newTopLeftCell.Y; j < oldTopLeftCell.Y; j++)
{
mCollisionGrid.Cells[i, j].AddCollisionUnit(unit);
}
// add bottom
for (int j = oldBottomRightCell.Y + 1; j <= newBottomRightCell.Y; j++)
{
mCollisionGrid.Cells[i, j].AddCollisionUnit(unit);
}
}
}
}
}
else if (unit.GetCollisionType() == CollisionUnit.CollisionType.COLLISION_LINE)
{
oldLineStart = unit.GetLineStart();
oldLineEnd = unit.GetLineEnd();
// TODO: put in appropriate cells
}
}
