|
public static ComposeSpeed ( System.Vector2 speeds ) : float>.Tuple |
||
| speeds | System.Vector2 | |
| return | float>.Tuple | |
private void InelasticCollision(IForwardMovablePhysicalEntity target, IForwardMovablePhysicalEntity source,
float diffAngle)
{
Vector2 decomposedSpeedTarget = Utils.DecomposeSpeed(target.ForwardSpeed, target.Direction, diffAngle);
Vector2 decomposedSpeedSource = Utils.DecomposeSpeed(source.ForwardSpeed, source.Direction, diffAngle);
float v1 = decomposedSpeedTarget.Y;
float v2 = decomposedSpeedSource.Y;
float m1 = target.Weight;
float m2 = source.Weight;
float newSpeedTargetAndSource = (m1 * v1 + m2 * v2) / (m1 + m2);
decomposedSpeedTarget.Y = newSpeedTargetAndSource;
decomposedSpeedSource.Y = newSpeedTargetAndSource;
Tuple <float, float> composedSpeedTarget = Utils.ComposeSpeed(decomposedSpeedTarget, diffAngle);
Tuple <float, float> composedSpeedSource = Utils.ComposeSpeed(decomposedSpeedSource, diffAngle);
float targetSpeed = composedSpeedTarget.Item1;
float sourceSpeed = composedSpeedSource.Item1;
target.ForwardSpeed = targetSpeed > m_collisionChecker.MaximumGameObjectSpeed
? m_collisionChecker.MaximumGameObjectSpeed
: targetSpeed;
target.Direction = composedSpeedTarget.Item2;
source.ForwardSpeed = sourceSpeed > m_collisionChecker.MaximumGameObjectSpeed
? m_collisionChecker.MaximumGameObjectSpeed
: sourceSpeed;
source.Direction = composedSpeedSource.Item2;
}
private void ElasticCollision(IForwardMovablePhysicalEntity target, IForwardMovablePhysicalEntity source,
float diffAngle)
{
Vector2 decomposedSpeedTarget = Utils.DecomposeSpeed(target.ForwardSpeed, target.Direction, diffAngle);
Vector2 decomposedSpeedSource = Utils.DecomposeSpeed(source.ForwardSpeed, source.Direction, diffAngle);
float v1 = decomposedSpeedTarget.Y;
float v2 = decomposedSpeedSource.Y;
float m1 = target.Weight;
float m2 = source.Weight;
float originalEnergy = target.ForwardSpeed * target.ForwardSpeed * m1 +
source.ForwardSpeed * source.ForwardSpeed * m2;
double p = m1 * v1 + m2 * v2; // P = momentum
double d = 4.0 * m1 * m1 * m2 * m2 * (v1 - v2) * (v1 - v2); // D = determinant
float v2A = (float)((2 * p * m2 + Math.Sqrt(d)) / (2 * (m1 * m2 + m2 * m2)));
float v2B = (float)((2 * p * m2 - Math.Sqrt(d)) / (2 * (m1 * m2 + m2 * m2)));
float newSourceSpeed = v2A;
if (Math.Abs(v2A - v2) < Math.Abs(v2B - v2)) // one of the results is identity
{
newSourceSpeed = v2B;
}
float newTargetSpeed = (m1 * v1 + m2 * v2 - m2 * newSourceSpeed) / m1;
/*
* float E2C = v1 * v1 * m1 + v2 * v2 * m2;
* float E2D = newTargetSpeed * newTargetSpeed * m1 + newSourceSpeed * newSourceSpeed * m2;
* Debug.Assert(Math.Abs(E2C - E2D) < 0.000001); // energy conservation check */
decomposedSpeedTarget.Y = newTargetSpeed;
decomposedSpeedSource.Y = newSourceSpeed;
Tuple <float, float> composedSpeedTarget = Utils.ComposeSpeed(decomposedSpeedTarget, diffAngle);
Tuple <float, float> composedSpeedSource = Utils.ComposeSpeed(decomposedSpeedSource, diffAngle);
float targetSpeed = composedSpeedTarget.Item1;
float sourceSpeed = composedSpeedSource.Item1;
float finalEnergy = targetSpeed * targetSpeed * m1 + sourceSpeed * sourceSpeed * m2;
Debug.Assert(Math.Abs(originalEnergy - finalEnergy) < 0.01);
target.ForwardSpeed = targetSpeed > m_collisionChecker.MaximumGameObjectSpeed
? m_collisionChecker.MaximumGameObjectSpeed
: targetSpeed;
target.Direction = composedSpeedTarget.Item2;
source.ForwardSpeed = sourceSpeed > m_collisionChecker.MaximumGameObjectSpeed
? m_collisionChecker.MaximumGameObjectSpeed
: sourceSpeed;
source.Direction = composedSpeedSource.Item2;
}
