/// <summary>
/// Checks if this wall blocks
/// a view ray from Start to End
/// </summary>
/// <param name="Start"></param>
/// <param name="End"></param>
/// <returns>True if blocked, false if OK</returns>
public bool IsBlockingSight(V3 Start, V3 End)
{
V2 P1 = GetP1();
V2 P2 = GetP2();
// 2D
V2 Start2D = new V2(Start.X, Start.Z);
V2 End2D = new V2(End.X, End.Z);
// calculate the sides of the points (returns -1, 0 or 1)
int startside = Start2D.GetSide(P1, P2);
int endside = End2D.GetSide(P1, P2);
// if points are not on same side
// the infinite lines cross
if (startside != endside)
{
// verify also the finite line segments cross
V2 intersect;
if (MathUtil.IntersectLineLine(Start2D, End2D, P1, P2, out intersect))
{
// the vector/ray between start and end
V3 diff = End - Start;
// solve 3d linear equation to get rayheight R2
// (height of possible intersection)
//
// ( R1 ) (P1) (Q1)
// ( R2 ) = (P2) + lambda * (Q2)
// ( R3 ) (P3) (Q3)
//
// using:
// R = intersect
// P = Start
// Q = diff (Direction)
// get lambda scale
Real lambda = 1.0f;
if (diff.X != 0)
{
lambda = (intersect.X - Start.X) / diff.X;
}
else if (diff.Z != 0)
{
lambda = (intersect.Y - Start.Z) / diff.Z;
}
// calculate the rayheight based on linear 3d equation
Real rayheight = Start.Y + lambda * diff.Y;
// compare height with wallheights
// use average of both endpoints (in case its sloped)
// do not care about the sides
Real h3 = (Z3 + ZZ3) / 2.0f;
Real h2 = (Z2 + ZZ2) / 2.0f;
Real h1 = (Z1 + ZZ1) / 2.0f;
Real h0 = (Z0 + ZZ0) / 2.0f;
bool a, b;
// test upper part
a = (LeftSide != null && LeftSide.ResourceUpper != null && (LeftSide.Flags.IsNoLookThrough || !LeftSide.Flags.IsTransparent));
b = (RightSide != null && RightSide.ResourceUpper != null && (RightSide.Flags.IsNoLookThrough || !RightSide.Flags.IsTransparent));
if ((a || b) &&
rayheight < h3 &&
rayheight > h2)
{
return(true);
}
// test middle part
a = (LeftSide != null && LeftSide.ResourceMiddle != null && (LeftSide.Flags.IsNoLookThrough || !LeftSide.Flags.IsTransparent));
b = (RightSide != null && RightSide.ResourceMiddle != null && (RightSide.Flags.IsNoLookThrough || !RightSide.Flags.IsTransparent));
if ((a || b) &&
rayheight < h2 &&
rayheight > h1)
{
return(true);
}
// test lower part (nolookthrough)
a = (LeftSide != null && LeftSide.ResourceLower != null);
b = (RightSide != null && RightSide.ResourceLower != null);
if ((a || b) &&
rayheight < h1 &&
rayheight > h0)
{
return(true);
}
}
}
return(false);
}
public void GetSide()
{
int expected;
int returned;
V2 s;
V2 p1, p2;
/**************************************************/
// --- TEST ---
// p1=p2=s=0, no line
s = new V2(0.0f, 0.0f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(0.0f, 0.0f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
// --- TEST ---
// p1=s
s = new V2(0.0f, 0.0f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(0.0f, 1.0f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
// --- TEST ---
// p2=s
s = new V2(0.0f, 1.0f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(0.0f, 1.0f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
/**************************************************/
// --- TEST ---
// s is somewhere on line
s = new V2(0.5f, 0.5f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(1.0f, 1.0f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
// --- TEST ---
// s is somewhere on line
s = new V2(-0.5f, -0.5f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(-1.0f, -1.0f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
// --- TEST ---
// s is somewhere on line
s = new V2(-0.5f, 0.5f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(-1.0f, 1.0f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
// --- TEST ---
// s is somewhere on line
s = new V2(0.5f, -0.5f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(1.0f, -1.0f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
/**************************************************/
// --- TEST ---
// s is not on line segment, but on same infinite line
s = new V2(2.0f, 2.0f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(1.0f, 1.0f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
// --- TEST ---
// s is not on line segment, but on same infinite line
s = new V2(-2.0f, -2.0f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(1.0f, 1.0f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
// --- TEST ---
// s is not on line segment, but very far on same infinite line
s = new V2(-2000000.0f, -2000000.0f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(1.0f, 1.0f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
// --- TEST ---
// s is left of line, but close (in bbox)
s = new V2(0.45f, 0.55f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(1.0f, 1.0f);
expected = 1;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
// --- TEST ---
// s is left of line and far away (outside bbox)
s = new V2(0.0f, 1000.0f);
p1 = new V2(0.0f, 0.0f);
p2 = new V2(1.0f, 1.0f);
expected = 1;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
// --- TEST ---
// s is on line
s = new V2(14304f, 32512f);
p1 = new V2(15872f, 32512f);
p2 = new V2(3433.6f, 32512f);
expected = 0;
returned = s.GetSide(p1, p2);
Assert.AreEqual(expected, returned);
}
/// <summary>
/// Checks if this wall blocks a
/// move between Start and End
/// </summary>
/// <param name="Start">A 3D location</param>
/// <param name="End">A 2D location</param>
/// <param name="PlayerHeight">Height of the player for ceiling collisions</param>
/// <returns></returns>
public bool IsBlocking(V3 Start, V2 End, Real PlayerHeight)
{
V2 P1 = GetP1();
V2 P2 = GetP2();
V2 Start2D = new V2(Start.X, Start.Z);
// calculate the sides of the points (returns -1, 0 or 1)
int startside = Start2D.GetSide(P1, P2);
int endside = End.GetSide(P1, P2);
// if points are not on same side
// the infinite lines cross
if (startside != endside)
{
// verify also the finite line segments cross
V2 intersect;
if (MathUtil.IntersectLineLine(Start2D, End, P1, P2, out intersect))
{
// verify the side we've crossed is flaggged as "nonpassable"
// if so, we actually have a collision
if ((startside < 0 && LeftSide != null && !LeftSide.Flags.IsPassable) ||
(startside > 0 && RightSide != null && !RightSide.Flags.IsPassable))
{
return(true);
}
// still check the stepheight from oldheight to new floor if passable
// for too high steps
Real endheight = 0.0f;
Real diff;
if (endside <= 0 && LeftSector != null)
{
endheight = LeftSector.CalculateFloorHeight((int)End.X, (int)End.Y, true);
}
else if (endside > 0 && RightSector != null)
{
endheight = RightSector.CalculateFloorHeight((int)End.X, (int)End.Y, true);
}
diff = endheight - Start.Y;
// diff is bigger than max. step height, we have a collision
if (diff > GeometryConstants.MAXSTEPHEIGHT)
{
return(true);
}
// check the ceiling heights
if (endside <= 0 && LeftSector != null)
{
endheight = LeftSector.CalculateCeilingHeight((int)End.X, (int)End.Y);
}
else if (endside > 0 && RightSector != null)
{
endheight = RightSector.CalculateCeilingHeight((int)End.X, (int)End.Y);
}
// diff is bigger than max. step height, we have a collision
if (endheight < Start.Y + PlayerHeight)
{
return(true);
}
}
}
return(false);
}
