//given a plane and a ray this function determins how far along the ray
//an interestion occurs. Returns negative if the ray is parallel
public static double DistanceToRayPlaneIntersection(Vector2D RayOrigin,
Vector2D RayHeading,
Vector2D PlanePoint, //any point on the plane
Vector2D PlaneNormal)
{
double d = -PlaneNormal.Dot(PlanePoint);
double numer = PlaneNormal.Dot(RayOrigin) + d;
double denom = PlaneNormal.Dot(RayHeading);
// normal is parallel to vector
if ((denom < 0.000001) && (denom > -0.000001))
{
return(-1.0);
}
return(-(numer / denom));
}
//------------------ isSecondInFOVOfFirst -------------------------------------
//
// returns true if the target position is in the field of view of the entity
// positioned at posFirst facing in facingFirst
//-----------------------------------------------------------------------------
public static bool isSecondInFOVOfFirst(Vector2D posFirst,
Vector2D facingFirst,
Vector2D posSecond,
double fov)
{
Vector2D toTarget = Vec2DNormalize(posSecond - posFirst);
return(facingFirst.Dot(toTarget) >= Math.Cos(fov / 2.0));
}
//----------------------------- DoRayCircleIntersect --------------------------
public static bool DoRayCircleIntersect(Vector2D RayOrigin,
Vector2D RayHeading,
Vector2D CircleOrigin,
double radius)
{
Vector2D ToCircle = CircleOrigin - RayOrigin;
double length = ToCircle.Length();
double v = ToCircle.Dot(RayHeading);
double d = radius * radius - (length * length - v * v);
// If there was no intersection, return -1
return(d < 0.0);
}
//--------------------- PointToLocalSpace --------------------------------
//
//------------------------------------------------------------------------
public static Vector2D PointToLocalSpace(Vector2D point,
Vector2D AgentHeading,
Vector2D AgentSide,
Vector2D AgentPosition)
{
//make a copy of the point
Vector2D TransPoint = new Vector2D(point.X, point.Y);
//create a transformation matrix
C2DMatrix matTransform = new C2DMatrix();
double Tx = -AgentPosition.Dot(AgentHeading);
double Ty = -AgentPosition.Dot(AgentSide);
//create the transformation matrix
matTransform._11(AgentHeading.X); matTransform._12(AgentSide.X);
matTransform._21(AgentHeading.Y); matTransform._22(AgentSide.Y);
matTransform._31(Tx); matTransform._32(Ty);
//now transform the vertices
matTransform.TransformVector2D(TransPoint);
return(TransPoint);
}
//-------------------------- GetRayCircleIntersec -----------------------------
public static double GetRayCircleIntersect(Vector2D RayOrigin,
Vector2D RayHeading,
Vector2D CircleOrigin,
double radius)
{
Vector2D ToCircle = CircleOrigin - RayOrigin;
double length = ToCircle.Length();
double v = ToCircle.Dot(RayHeading);
double d = radius * radius - (length * length - v * v);
// If there was no intersection, return -1
if (d < 0.0)
{
return(-1.0);
}
// Return the distance to the [first] intersecting point
return(v - Math.Sqrt(d));
}
public static Enum_Span_Type WhereIsPoint(Vector2D point,
Vector2D PointOnPlane, //any point on the plane
Vector2D PlaneNormal)
{
Vector2D dir = PointOnPlane - point;
double d = dir.Dot(PlaneNormal);
if (d < -0.000001)
{
return(Enum_Span_Type.plane_front);
}
else if (d > 0.000001)
{
return(Enum_Span_Type.plane_backside);
}
return(Enum_Span_Type.on_plane);
}
//------------------ isSecondInFOVOfFirst -------------------------------------
//
// returns true if the target position is in the field of view of the entity
// positioned at posFirst facing in facingFirst
//-----------------------------------------------------------------------------
public static bool isSecondInFOVOfFirst(Vector2D posFirst,
Vector2D facingFirst,
Vector2D posSecond,
double fov)
{
Vector2D toTarget = Vec2DNormalize(posSecond - posFirst);
return facingFirst.Dot(toTarget) >= Math.Cos(fov / 2.0);
}
//given a plane and a ray this function determins how far along the ray
//an interestion occurs. Returns negative if the ray is parallel
public static double DistanceToRayPlaneIntersection(Vector2D RayOrigin,
Vector2D RayHeading,
Vector2D PlanePoint, //any point on the plane
Vector2D PlaneNormal)
{
double d = -PlaneNormal.Dot(PlanePoint);
double numer = PlaneNormal.Dot(RayOrigin) + d;
double denom = PlaneNormal.Dot(RayHeading);
// normal is parallel to vector
if ((denom < 0.000001) && (denom > -0.000001))
{
return (-1.0);
}
return -(numer / denom);
}
//--------------------- PointToLocalSpace --------------------------------
//
//------------------------------------------------------------------------
public static Vector2D PointToLocalSpace(Vector2D point,
Vector2D AgentHeading,
Vector2D AgentSide,
Vector2D AgentPosition)
{
//make a copy of the point
Vector2D TransPoint = new Vector2D(point.X, point.Y);
//create a transformation matrix
C2DMatrix matTransform = new C2DMatrix();
double Tx = -AgentPosition.Dot(AgentHeading);
double Ty = -AgentPosition.Dot(AgentSide);
//create the transformation matrix
matTransform._11(AgentHeading.X); matTransform._12(AgentSide.X);
matTransform._21(AgentHeading.Y); matTransform._22(AgentSide.Y);
matTransform._31(Tx); matTransform._32(Ty);
//now transform the vertices
matTransform.TransformVector2D( TransPoint);
return TransPoint;
}