public static Boolean Detect(BasicModel shot, Collidable item, Boolean isPigeon)
{
Vector3 boundingBox = item.GetBoundingBox();
Vector3 itemPos = item.GetPosition();
//get the shot's position, rotation and scale
Matrix shotMat = shot.GetWorld();
Vector3 shotPos;
Quaternion shotRotation;
Vector3 shotScale;
shotMat.Decompose(out shotScale, out shotRotation, out shotPos);
//offset to compensate for the camera location not being at the origin.
//camera loc is 0,0,100
itemPos.Z -= 100;
shotPos.Z -= 100;
//calculate the shot's distance from the origin
double shotDistance = Math.Sqrt(Math.Pow(shotPos.X, 2) + Math.Pow(shotPos.Y, 2) + Math.Pow(shotPos.Z, 2));
//normalize the shot's position vector so the distance is equal to 1.0
Vector3 shotNormalizedPos = new Vector3(shotPos.X / (float)shotDistance, shotPos.Y / (float)shotDistance, shotPos.Z / (float)shotDistance);
//don't try to check collision detection for shots that have already passed the target in depth
if ((item.GetDistance()+boundingBox.Z - shotDistance < 0) && isPigeon)
return false;
//laser gun effect
//multiply the normalized shot vector by the target's distance. The effect of this operation is that the shot's distance becomes equal to that of the target's,
//allowing us to simply check whether the shot is contained inside the target's bounding box to detect a hit.
shotNormalizedPos *= (float)Math.Sqrt(Math.Pow(itemPos.X, 2) + Math.Pow(itemPos.Y, 2) + Math.Pow(itemPos.Z, 2));
float xDiff = itemPos.X - shotNormalizedPos.X;
float yDiff = itemPos.Y - shotNormalizedPos.Y;
float zDiff = itemPos.Z - shotNormalizedPos.Z;
//hack to get the shot's vector to face the right way, since shots quickly gain a negative Z value while pidgeons always stay positive
if (isPigeon) zDiff = (zDiff < 0) ? -zDiff : zDiff;
//check to see if the shot is inside the bounding box
if (boundingBox.X / 2 > xDiff && (0 - (boundingBox.X / 2)) < xDiff &&
boundingBox.Y / 2 > yDiff && (0 - (boundingBox.Y / 2)) < yDiff)
{
if (isPigeon && boundingBox.Z / 2 > zDiff && (0 - (boundingBox.Z / 2)) < zDiff)
return true;
else if (!isPigeon)
return true;
}
return false;
}
