|
public GetCollisionPoint ( |
||
| other | The CollisionUnit to get the collision point from. | |
| return | Vector2 | |
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>
/// 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));
//}
}
}
