/// <summary>
///
/// </summary>
/// <param name="penData"></param>
/// <returns>bool willPenetrate, float penetrationDepth</returns>
protected virtual Tuple <bool, float> WillPen(TerminalBallisticsData penData)
{
ProjectileData projData = penData.projectile.projectileData;
VirtualPhysicsTransform physicsTransform = penData.projectile.physicsTransform;
//(assuming 0 degrees is hitting straight on)
//If angleWeHitTarget >= 80 degrees, then richochet
if (Vector3.Angle(physicsTransform.Velocity.normalized, -penData.hitInfo.normal) >= 80)
{
return(new Tuple <bool, float>(false, 0.0f)); //When Unity supports C#7, switch this to the new syntax
}
//Otherwise, do some more testing
float targetDensity = 1000.0f; //{TODO} Hook this up
//tex:
//$$stoppingDist=\sqrt[3]{\frac{projMass * initVel^2}{targetDensity*projCrossArea * projDragCoefficient}} $$
//Heavily simplified model
float stoppingDist =
Mathf.Pow( //3rd root
(projData.bulletMass * physicsTransform.VelocityMagnitude * physicsTransform.VelocityMagnitude) //{TODO} Make velocity relative to target
/
(targetDensity * projData.CrossSectionalArea * projData.GetDragCoefficient(physicsTransform.Velocity.magnitude / 343.0f)) //{TODO} Rewrite correctly!
, (1.0f / 3.0f)
);
return(new Tuple <bool, float>(stoppingDist >= projData.noseLength, stoppingDist));
}
//{TODO} Damn this method is long...
protected virtual void Penetrate(TerminalBallisticsData penData, float stoppingDist)
{
ProjectileData projData = penData.projectile.projectileData;
VirtualPhysicsTransform physicsTransform = penData.projectile.physicsTransform;
float targetDensity = 1000.0f; //{TODO} Hook this up
//343.0f - Temporary hardcoded value - 1 mach in air ~= 343 m/s
ThicknessData objectThickness =
ProjectileHelper.FindThickness(
physicsTransform.PrevPosition,
physicsTransform.Velocity.normalized,
(rCH) => rCH.collider.gameObject == penData.hitInfo.collider.gameObject); //Only colliders on this object
Debug.Log($"Thickness: {objectThickness.thickness}m");
//{TODO} Add some check to see if the object thickness was even found
//If the projectile stops mid-object, de-activate it
if (stoppingDist <= objectThickness.thickness)
{
penData.projectile.Active = false;
Debug.Log($"Stopped after penetrating {stoppingDist}m");
return;
}
//Otherwise, see how fast we come out the other side
physicsTransform.Position = objectThickness.exitPosition;
//tex:
//$$ v=\sqrt{-\frac{ACpx^3}{m}+u^2}$$
physicsTransform.VelocityMagnitude =
Mathf.Sqrt(
-
(
(
projData.CrossSectionalArea *
projData.GetDragCoefficient(physicsTransform.Velocity.magnitude / 343.0f) *
targetDensity *
objectThickness.thickness * objectThickness.thickness * objectThickness.thickness
)
/
projData.bulletMass
)
+ (physicsTransform.VelocityMagnitude * physicsTransform.VelocityMagnitude)
);
//Modify the exit direction depending on the projectile velocity
//{TODO} Rewrite!
float range = 0.25f;
physicsTransform.VelocityDirection +=
Vector3.Lerp(
new Vector3(
CryptoRand.Range(-range, range),
CryptoRand.Range(-range, range),
CryptoRand.Range(-range, range)),
Vector3.zero,
Mathf.Clamp(1 / physicsTransform.VelocityMagnitude, 0, 1)
);
Debug.Log($"Stopping distance: {stoppingDist}");
Debug.Log($"Fully penetrated with an exit velocity of {physicsTransform.Velocity.magnitude}m/s");
}
