public void Collide(TimeSpan frameDuration, IColliadableAxisAlignedRectangle object1, ICollidableCircle object2)
{
// Calculate the 4 corners of the rectangle.
Vector2 rectVertex_v1 = new Vector2(object1.Position.X - (object1.Width / 2), object1.Position.Y - (object1.Height / 2));
Vector2 rectVertex_v2 = new Vector2(object1.Position.X - (object1.Width / 2), object1.Position.Y + (object1.Height / 2));
Vector2 rectVertex_v3 = new Vector2(object1.Position.X + (object1.Width / 2), object1.Position.Y + (object1.Height / 2));
Vector2 rectVertex_v4 = new Vector2(object1.Position.X + (object1.Width / 2), object1.Position.Y - (object1.Height / 2));
// Calculate the 4 corners of the outer collision zone (based on the size of the circle).
Vector2 rectOuterVertex_v1 = new Vector2(object1.Position.X - (object1.Width / 2) - object2.Radius, object1.Position.Y - (object1.Height / 2) - object2.Radius);
Vector2 rectOuterVertex_v2 = new Vector2(object1.Position.X - (object1.Width / 2) - object2.Radius, object1.Position.Y + (object1.Height / 2) + object2.Radius);
Vector2 rectOuterVertex_v3 = new Vector2(object1.Position.X + (object1.Width / 2) + object2.Radius, object1.Position.Y + (object1.Height / 2) + object2.Radius);
Vector2 rectOuterVertex_v4 = new Vector2(object1.Position.X + (object1.Width / 2) + object2.Radius, object1.Position.Y - (object1.Height / 2) - object2.Radius);
// Calculate the 4 outer zone sides.
Vector2 rectOuterSide1 = rectOuterVertex_v2 - rectOuterVertex_v1;
Vector2 rectOuterSide2 = rectOuterVertex_v3 - rectOuterVertex_v2;
Vector2 rectOuterSide3 = rectOuterVertex_v4 - rectOuterVertex_v3;
Vector2 rectOuterSide4 = rectOuterVertex_v1 - rectOuterVertex_v4;
// Calcualte the vectors & distances to each of the outer corners.
Vector2 vecToOuterV1 = object2.Position - rectOuterVertex_v1;
Vector2 vecToOuterV2 = object2.Position - rectOuterVertex_v2;
Vector2 vecToOuterV3 = object2.Position - rectOuterVertex_v3;
Vector2 vecToOuterV4 = object2.Position - rectOuterVertex_v4;
float distToOuterSide1 = ((rectOuterSide1 * vecToOuterV1).Length() / rectOuterSide1.Length());
float distToOuterSide2 = ((rectOuterSide2 * vecToOuterV2).Length() / rectOuterSide2.Length());
float distToOuterSide3 = ((rectOuterSide3 * vecToOuterV3).Length() / rectOuterSide3.Length());
float distToOuterSide4 = ((rectOuterSide4 * vecToOuterV4).Length() / rectOuterSide4.Length());
// Calcualte the vectors & distances to each of the actual corners.
Vector2 vecToVertex1 = object2.Position - rectVertex_v1;
Vector2 vecToVertex2 = object2.Position - rectVertex_v2;
Vector2 vecToVertex3 = object2.Position - rectVertex_v3;
Vector2 vecToVertex4 = object2.Position - rectVertex_v4;
float distToVetex1 = vecToVertex1.Length();
float distToVetex2 = vecToVertex2.Length();
float distToVetex3 = vecToVertex3.Length();
float distToVetex4 = vecToVertex4.Length();
bool isPastSide1 = Vector2.Dot(vecToOuterV1, rectOuterSide1) > 0;
bool isPastSide2 = Vector2.Dot(vecToOuterV2, rectOuterSide2) > 0;
bool isPastSide3 = Vector2.Dot(vecToOuterV3, rectOuterSide3) > 0;
bool isPastSide4 = Vector2.Dot(vecToOuterV4, rectOuterSide4) > 0;
// Code for calculating the angle between. Not needed any more.
//float c = v / (vecToV1.Length() * rect_side1.Length());
//var angleBetween = MathHelper.ToDegrees((float)Math.Acos(c));
/* There are 8 collision zones:
* _____________
* : 1 __8__ 7 :
* : | | :
* : 2 | | 6 :
* : |___| :
* :_3___4___5_:
*
* Zones 2, 4, 6 & 8 are collisions with a flat surface of the AA rectangle.
* Zones 1, 3, 5 & 7 are *potential* collisions with a corner.
* In these zones we must test again that the circle has actually hit the corner of the AA rect.
*/
bool collision = false;
Vector2 collisionPlane = Vector2.Zero;
Vector2 normalPlane = Vector2.Zero;
if (isPastSide1 && isPastSide2 && isPastSide3 && isPastSide4)
{
// The centre of the cirle is somewhere within the outer collision zone.
// Now figure out which zone it's in and find the collision & normal planes.
if (distToOuterSide1 < object2.Radius)
{
// Zones 1, 8, 7
if (distToOuterSide2 < object2.Radius)
{
// Zone 1.
collision = distToVetex1 < object2.Radius;
if (collision)
{
normalPlane = vecToVertex1;
normalPlane.Normalize();
collisionPlane = new Vector2(-normalPlane.Y, normalPlane.X);
collisionPlane.Normalize();
}
}
else if (distToOuterSide3 < object2.Radius)
{
// Zone 7.
collision = distToVetex2 < object2.Radius;
if (collision)
{
normalPlane = vecToVertex4;
normalPlane.Normalize();
collisionPlane = new Vector2(-normalPlane.Y, normalPlane.X);
collisionPlane.Normalize();
}
}
else
{
// Zone 8.
collision = true;
collisionPlane = rectOuterSide4;
collisionPlane.Normalize();
normalPlane = new Vector2(-1 * collisionPlane.Y, collisionPlane.X);
normalPlane.Normalize();
}
}
else if (distToOuterSide3 < object2.Radius)
{
// Zones 3, 4, 5.
if (distToOuterSide2 < object2.Radius)
{
// Zone 3.
collision = distToVetex3 < object2.Radius;
if (collision)
{
normalPlane = vecToVertex2;
normalPlane.Normalize();
collisionPlane = new Vector2(-normalPlane.Y, normalPlane.X);
collisionPlane.Normalize();
}
}
else if (distToOuterSide3 < object2.Radius)
{
// Zone 5.
collision = distToVetex4 < object2.Radius;
if (collision)
{
normalPlane = vecToVertex3;
normalPlane.Normalize();
collisionPlane = new Vector2(-normalPlane.Y, normalPlane.X);
collisionPlane.Normalize();
}
}
else
{
// Zone 4.
collision = true;
collisionPlane = rectOuterSide2;
collisionPlane.Normalize();
normalPlane = new Vector2(-1 * collisionPlane.Y, collisionPlane.X);
normalPlane.Normalize();
}
}
else if (distToOuterSide2 < 50)
{
// Zone 2.
collision = true;
collisionPlane = rectOuterSide1;
collisionPlane.Normalize();
normalPlane = new Vector2(-1 * collisionPlane.Y, collisionPlane.X);
normalPlane.Normalize();
}
else if (distToOuterSide4 < 50)
{
// Zone 6.
collision = true;
collisionPlane = rectOuterSide3;
collisionPlane.Normalize();
normalPlane = new Vector2(-1 * collisionPlane.Y, collisionPlane.X);
normalPlane.Normalize();
}
if (collision)
{
// Once we know there was a collision, we can apply it to the objects.
Vector2 vel1_after;
Vector2 vel2_after;
CalculatePostCollisionVelocityVectors(object1, object2, normalPlane, collisionPlane, out vel1_after, out vel2_after);
// Set the objects new positions and velocities.
object1.SetVelocity(vel1_after);
object2.SetVelocity(vel2_after);
}
}
}
public void Collide(TimeSpan frameDuration, IColliadableAxisAlignedRectangle object1, ICollidableCircle object2)
{
// Calculate the 4 corners of the rectangle.
Vector2 rectVertex_v1 = new Vector2(object1.Position.X - (object1.Width / 2), object1.Position.Y - (object1.Height / 2));
Vector2 rectVertex_v2 = new Vector2(object1.Position.X - (object1.Width / 2), object1.Position.Y + (object1.Height / 2));
Vector2 rectVertex_v3 = new Vector2(object1.Position.X + (object1.Width / 2), object1.Position.Y + (object1.Height / 2));
Vector2 rectVertex_v4 = new Vector2(object1.Position.X + (object1.Width / 2), object1.Position.Y - (object1.Height / 2));
// Calculate the 4 corners of the outer collision zone (based on the size of the circle).
Vector2 rectOuterVertex_v1 = new Vector2(object1.Position.X - (object1.Width / 2) - object2.Radius, object1.Position.Y - (object1.Height / 2) - object2.Radius);
Vector2 rectOuterVertex_v2 = new Vector2(object1.Position.X - (object1.Width / 2) - object2.Radius, object1.Position.Y + (object1.Height / 2) + object2.Radius);
Vector2 rectOuterVertex_v3 = new Vector2(object1.Position.X + (object1.Width / 2) + object2.Radius, object1.Position.Y + (object1.Height / 2) + object2.Radius);
Vector2 rectOuterVertex_v4 = new Vector2(object1.Position.X + (object1.Width / 2) + object2.Radius, object1.Position.Y - (object1.Height / 2) - object2.Radius);
// Calculate the 4 outer zone sides.
Vector2 rectOuterSide1 = rectOuterVertex_v2 - rectOuterVertex_v1;
Vector2 rectOuterSide2 = rectOuterVertex_v3 - rectOuterVertex_v2;
Vector2 rectOuterSide3 = rectOuterVertex_v4 - rectOuterVertex_v3;
Vector2 rectOuterSide4 = rectOuterVertex_v1 - rectOuterVertex_v4;
// Calcualte the vectors & distances to each of the outer corners.
Vector2 vecToOuterV1 = object2.Position - rectOuterVertex_v1;
Vector2 vecToOuterV2 = object2.Position - rectOuterVertex_v2;
Vector2 vecToOuterV3 = object2.Position - rectOuterVertex_v3;
Vector2 vecToOuterV4 = object2.Position - rectOuterVertex_v4;
float distToOuterSide1 = ((rectOuterSide1 * vecToOuterV1).Length() / rectOuterSide1.Length());
float distToOuterSide2 = ((rectOuterSide2 * vecToOuterV2).Length() / rectOuterSide2.Length());
float distToOuterSide3 = ((rectOuterSide3 * vecToOuterV3).Length() / rectOuterSide3.Length());
float distToOuterSide4 = ((rectOuterSide4 * vecToOuterV4).Length() / rectOuterSide4.Length());
// Calcualte the vectors & distances to each of the actual corners.
Vector2 vecToVertex1 = object2.Position - rectVertex_v1;
Vector2 vecToVertex2 = object2.Position - rectVertex_v2;
Vector2 vecToVertex3 = object2.Position - rectVertex_v3;
Vector2 vecToVertex4 = object2.Position - rectVertex_v4;
float distToVetex1 = vecToVertex1.Length();
float distToVetex2 = vecToVertex2.Length();
float distToVetex3 = vecToVertex3.Length();
float distToVetex4 = vecToVertex4.Length();
bool isPastSide1 = Vector2.Dot(vecToOuterV1, rectOuterSide1) > 0;
bool isPastSide2 = Vector2.Dot(vecToOuterV2, rectOuterSide2) > 0;
bool isPastSide3 = Vector2.Dot(vecToOuterV3, rectOuterSide3) > 0;
bool isPastSide4 = Vector2.Dot(vecToOuterV4, rectOuterSide4) > 0;
// Code for calculating the angle between. Not needed any more.
//float c = v / (vecToV1.Length() * rect_side1.Length());
//var angleBetween = MathHelper.ToDegrees((float)Math.Acos(c));
/* There are 8 collision zones:
* _____________
* : 1 __8__ 7 :
* : | | :
* : 2 | | 6 :
* : |___| :
* :_3___4___5_:
*
* Zones 2, 4, 6 & 8 are collisions with a flat surface of the AA rectangle.
* Zones 1, 3, 5 & 7 are *potential* collisions with a corner.
* In these zones we must test again that the circle has actually hit the corner of the AA rect.
*/
bool collision = false;
Vector2 collisionPlane = Vector2.Zero;
Vector2 normalPlane = Vector2.Zero;
if (isPastSide1 && isPastSide2 && isPastSide3 && isPastSide4)
{
// The centre of the cirle is somewhere within the outer collision zone.
// Now figure out which zone it's in and find the collision & normal planes.
if (distToOuterSide1 < object2.Radius)
{
// Zones 1, 8, 7
if (distToOuterSide2 < object2.Radius)
{
// Zone 1.
collision = distToVetex1 < object2.Radius;
if (collision)
{
normalPlane = vecToVertex1;
normalPlane.Normalize();
collisionPlane = new Vector2(-normalPlane.Y, normalPlane.X);
collisionPlane.Normalize();
}
}
else if (distToOuterSide3 < object2.Radius)
{
// Zone 7.
collision = distToVetex2 < object2.Radius;
if (collision)
{
normalPlane = vecToVertex4;
normalPlane.Normalize();
collisionPlane = new Vector2(-normalPlane.Y, normalPlane.X);
collisionPlane.Normalize();
}
}
else
{
// Zone 8.
collision = true;
collisionPlane = rectOuterSide4;
collisionPlane.Normalize();
normalPlane = new Vector2(-1 * collisionPlane.Y, collisionPlane.X);
normalPlane.Normalize();
}
}
else if (distToOuterSide3 < object2.Radius)
{
// Zones 3, 4, 5.
if (distToOuterSide2 < object2.Radius)
{
// Zone 3.
collision = distToVetex3 < object2.Radius;
if (collision)
{
normalPlane = vecToVertex2;
normalPlane.Normalize();
collisionPlane = new Vector2(-normalPlane.Y, normalPlane.X);
collisionPlane.Normalize();
}
}
else if (distToOuterSide3 < object2.Radius)
{
// Zone 5.
collision = distToVetex4 < object2.Radius;
if (collision)
{
normalPlane = vecToVertex3;
normalPlane.Normalize();
collisionPlane = new Vector2(-normalPlane.Y, normalPlane.X);
collisionPlane.Normalize();
}
}
else
{
// Zone 4.
collision = true;
collisionPlane = rectOuterSide2;
collisionPlane.Normalize();
normalPlane = new Vector2(-1 * collisionPlane.Y, collisionPlane.X);
normalPlane.Normalize();
}
}
else if (distToOuterSide2 < 50)
{
// Zone 2.
collision = true;
collisionPlane = rectOuterSide1;
collisionPlane.Normalize();
normalPlane = new Vector2(-1 * collisionPlane.Y, collisionPlane.X);
normalPlane.Normalize();
}
else if (distToOuterSide4 < 50)
{
// Zone 6.
collision = true;
collisionPlane = rectOuterSide3;
collisionPlane.Normalize();
normalPlane = new Vector2(-1 * collisionPlane.Y, collisionPlane.X);
normalPlane.Normalize();
}
if (collision)
{
// Once we know there was a collision, we can apply it to the objects.
Vector2 vel1_after;
Vector2 vel2_after;
CalculatePostCollisionVelocityVectors(object1, object2, normalPlane, collisionPlane, out vel1_after, out vel2_after);
// Set the objects new positions and velocities.
object1.SetVelocity(vel1_after);
object2.SetVelocity(vel2_after);
}
}
}