/**
* <summary>
* Sphere must be the first, not moving object in center
* just the second object can move
* </summary>
*/
public CollisionResponse CheckSimplified(CollisionSimplifiedScenario scenario)
{
CollisionResponse test = null;
// 1. first escape scenario -point is too far to collide with sphere
// it may happen if (|point center| - R) ^2 <= movement ^2
double R1 = scenario.ColliderShape1.CalculateMaximumRadius;
double R2 = scenario.ColliderShape2.CalculateMaximumRadius;
Vector3D totalDisplacement;
totalDisplacement = scenario.Linear.Velocity * scenario.Linear.DeltaTime;
Vector3D DistanceToSphereCenter = new Point3D(0, 0, 0) - scenario.Linear.StartingPosition;
Vector3D absoluteminimumDistanceToSphere = DistanceToSphereCenter.Abs();
absoluteminimumDistanceToSphere.X = Math.Max(0, absoluteminimumDistanceToSphere.X - R1 - R2);
absoluteminimumDistanceToSphere.Y = Math.Max(0, absoluteminimumDistanceToSphere.Y - R1 - R2);
absoluteminimumDistanceToSphere.Z = Math.Max(0, absoluteminimumDistanceToSphere.Z - R1 - R2);
if (absoluteminimumDistanceToSphere.LengthSquared > totalDisplacement.LengthSquared)
{
return(test);
}
// 2. check direction of displacement. If point does not move towards the center
// escape, as can never collide with sphere
Vector3D VelocityDirectionNormalized = new Vector3D(totalDisplacement.X, totalDisplacement.Y, totalDisplacement.Z);
VelocityDirectionNormalized.Normalize();
Vector3D PointTowardsSphereCenter = DistanceToSphereCenter;
double displacementDirection = Vector3D.DotProduct(VelocityDirectionNormalized, PointTowardsSphereCenter);
// does not move towards the sphere center
if (displacementDirection < 0)
{
return(test);
}
// will be close but too far to sphere
double RadiusSum = (R1 + R2);
double RadiusSumSquared = RadiusSum * RadiusSum;
double SquaredMinimumDistanceEverOnVelocityVector = DistanceToSphereCenter.LengthSquared - (displacementDirection * displacementDirection);
if (SquaredMinimumDistanceEverOnVelocityVector > RadiusSumSquared)
{
return(test);
}
//double MinimumDistanceEverOnVelocityVector = Math.Sqrt(SquaredMinimumDistanceEverOnVelocityVector);
double MinimumCollisionLength = Math.Sqrt(RadiusSumSquared - SquaredMinimumDistanceEverOnVelocityVector);
Vector3D MinimumCollisionVector = VelocityDirectionNormalized * (displacementDirection - MinimumCollisionLength);
// the last escape, collision would happen, but in next frames
if (MinimumCollisionVector.LengthSquared > totalDisplacement.LengthSquared)
{
return(test);
}
double k;
if (scenario.Linear.Velocity.X != 0)
{
k = MinimumCollisionVector.X / totalDisplacement.X;
}
else
if (scenario.Linear.Velocity.Y != 0)
{
k = MinimumCollisionVector.Y / totalDisplacement.Y;
}
else
if (scenario.Linear.Velocity.Z != 0)
{
k = MinimumCollisionVector.Z / totalDisplacement.Z;
}
else
{
k = 0;
}
// spheres were intersecting before test
if (k <= 0)
{
return(test);
}
double deltaTime = k * scenario.Linear.DeltaTime;
test = new CollisionResponse(
(float)deltaTime,
scenario.Linear.StartingPosition + MinimumCollisionVector
);
return(test);
}
/**
* <summary>
* Sphere must be the first, not moving object in center
* just the second object can move
* </summary>
*/
public CollisionResponse CheckSimplified(CollisionSimplifiedScenario scenario)
{
CollisionResponse test = null;
// 1. first escape scenario -point is too far to collide with sphere
// it may happen if (|point center| - R) ^2 <= movement ^2
double R = scenario.ColliderShape1.CalculateMaximumRadius;
Vector3D totalDisplacement;
totalDisplacement = scenario.Linear.Velocity * scenario.Linear.DeltaTime;
Vector3D minimumDistanceToSphere = new Point3D(0, 0, 0) - scenario.Linear.StartingPosition;
Vector3D absoluteminimumDistanceToSphere = minimumDistanceToSphere.Abs();
absoluteminimumDistanceToSphere.X = Math.Max(0, absoluteminimumDistanceToSphere.X - R);
absoluteminimumDistanceToSphere.Y = Math.Max(0, absoluteminimumDistanceToSphere.Y - R);
absoluteminimumDistanceToSphere.Z = Math.Max(0, absoluteminimumDistanceToSphere.Z - R);
if (absoluteminimumDistanceToSphere.LengthSquared > totalDisplacement.LengthSquared)
{
return(test);
}
// 2. check direction of displacement. If point does not move towards the center
// escape, as can never collide with sphere
Vector3D PointTowardsSphereCenter = minimumDistanceToSphere;
double displacementDirection = Vector3D.DotProduct(PointTowardsSphereCenter, totalDisplacement);
if (displacementDirection < 0)
{
return(test);
}
// 3. Check calculation
Vector3D VelocityDirectionNormalized = new Vector3D(totalDisplacement.X, totalDisplacement.Y, totalDisplacement.Z);
VelocityDirectionNormalized.Normalize();
double lo = Vector3D.DotProduct(VelocityDirectionNormalized, PointTowardsSphereCenter);
Vector3D TowardCenterAbsolute = PointTowardsSphereCenter.Abs();
double sqareRootValue = lo * lo - TowardCenterAbsolute.LengthSquared + R * R;
// 3a. escape condition
if (sqareRootValue < 0)
{
return(test);
}
double squareCalculatedValue = Math.Sqrt(sqareRootValue);
double d1 = Math.Abs(-lo + squareCalculatedValue);
double d2 = Math.Abs(-lo - squareCalculatedValue);
double d = Math.Min(d1, d2);
Vector3D FastestCollisionLength = d * VelocityDirectionNormalized;
// the last escape, collision would happen, but in next frames
if (FastestCollisionLength.LengthSquared > totalDisplacement.LengthSquared)
{
return(test);
}
test = new CollisionResponse(
(float)d,
scenario.Linear.StartingPosition + FastestCollisionLength
);
return(test);
}
