public Q3BSPCollisionData TraceRay(Vector3 startPosition, Vector3 endPosition)
{
Q3BSPCollisionData collision = new Q3BSPCollisionData();
collision.type = Q3BSPCollisionType.Ray;
return(Trace(startPosition, endPosition, ref collision));
}
public Q3BSPCollisionData TraceSphere(Vector3 startPosition, Vector3 endPosition, float sphereRadius)
{
Q3BSPCollisionData collision = new Q3BSPCollisionData();
collision.type = Q3BSPCollisionType.Sphere;
collision.sphereRadius = sphereRadius;
return(Trace(startPosition, endPosition, ref collision));
}
public Q3BSPCollisionData TraceBox(Vector3 startPosition, Vector3 endPosition, Vector3 boxMinimums, Vector3 boxMaximums)
{
Q3BSPCollisionData collision = new Q3BSPCollisionData();
if (boxMinimums.X == 0 && boxMinimums.Y == 0 && boxMinimums.Z == 0 && boxMaximums.X == 0 && boxMaximums.Y == 0 && boxMaximums.Z == 0)
{
collision.type = Q3BSPCollisionType.Ray;
return(Trace(startPosition, endPosition, ref collision));
}
if (boxMaximums.X < boxMinimums.X)
{
float x = boxMaximums.X;
boxMaximums.X = boxMinimums.X;
boxMinimums.X = x;
}
if (boxMaximums.Y < boxMinimums.Y)
{
float y = boxMaximums.Y;
boxMaximums.Y = boxMinimums.Y;
boxMinimums.Y = y;
}
if (boxMaximums.Z < boxMinimums.Z)
{
float z = boxMaximums.Z;
boxMaximums.Z = boxMinimums.Z;
boxMinimums.Z = z;
}
Vector3 boxExtents = new Vector3();
boxExtents.X = Math.Max(Math.Abs(boxMaximums.X), Math.Abs(boxMinimums.X));
boxExtents.Y = Math.Max(Math.Abs(boxMaximums.Y), Math.Abs(boxMinimums.Y));
boxExtents.Z = Math.Max(Math.Abs(boxMaximums.Z), Math.Abs(boxMinimums.Z));
collision.type = Q3BSPCollisionType.Box;
collision.boxMinimums = boxMinimums;
collision.boxMaximums = boxMaximums;
collision.boxExtents = boxExtents;
return(Trace(startPosition, endPosition, ref collision));
}
private Q3BSPCollisionData Trace(Vector3 startPosition, Vector3 endPosition, ref Q3BSPCollisionData collision)
{
collision.startOutside = true;
collision.inSolid = false;
collision.ratio = 1.0f;
collision.startPosition = startPosition;
collision.endPosition = endPosition;
collision.collisionPoint = startPosition;
WalkNode(0, 0.0f, 1.0f, startPosition, endPosition, ref collision);
if (1.0f == collision.ratio)
{
collision.collisionPoint = endPosition;
}
else
{
collision.collisionPoint = startPosition + (collision.ratio - 0.002f) * (endPosition - startPosition);
}
return(collision);
}
private void CheckBrush(ref Q3BSPBrush brush, ref Q3BSPCollisionData cd)
{
float startFraction = -1.0f;
float endFraction = 1.0f;
bool startsOut = false;
bool endsOut = false;
for (int i = 0; i < brush.NumberOfSides; i++)
{
Q3BSPBrushSide brushSide = brushSides[brush.StartBrushSide + i];
Plane plane = planes[brushSide.PlaneIndex];
float startDistance = 0, endDistance = 0;
if (cd.type == Q3BSPCollisionType.Ray)
{
startDistance = Vector3.Dot(cd.startPosition, plane.Normal) - plane.D;
endDistance = Vector3.Dot(cd.endPosition, plane.Normal) - plane.D;
}
else if (cd.type == Q3BSPCollisionType.Sphere)
{
startDistance = Vector3.Dot(cd.startPosition, plane.Normal) - (plane.D + cd.sphereRadius);
endDistance = Vector3.Dot(cd.endPosition, plane.Normal) - (plane.D + cd.sphereRadius);
}
else if (cd.type == Q3BSPCollisionType.Box)
{
Vector3 offset = new Vector3();
if (plane.Normal.X < 0)
{
offset.X = cd.boxMaximums.X;
}
else
{
offset.X = cd.boxMinimums.X;
}
if (plane.Normal.Y < 0)
{
offset.Y = cd.boxMaximums.Y;
}
else
{
offset.Y = cd.boxMinimums.Y;
}
if (plane.Normal.Z < 0)
{
offset.Z = cd.boxMaximums.Z;
}
else
{
offset.Z = cd.boxMinimums.Z;
}
startDistance = (cd.startPosition.X + offset.X) * plane.Normal.X +
(cd.startPosition.Y + offset.Y) * plane.Normal.Y +
(cd.startPosition.Z + offset.Z) * plane.Normal.Z -
plane.D;
endDistance = (cd.endPosition.X + offset.X) * plane.Normal.X +
(cd.endPosition.Y + offset.Y) * plane.Normal.Y +
(cd.endPosition.Z + offset.Z) * plane.Normal.Z -
plane.D;
}
if (startDistance > 0)
{
startsOut = true;
}
if (endDistance > 0)
{
endsOut = true;
}
if (startDistance > 0 && endDistance > 0)
{
return;
}
if (startDistance <= 0 && endDistance <= 0)
{
continue;
}
if (startDistance > endDistance)
{
float fraction = (startDistance - Q3BSPConstants.Epsilon) / (startDistance - endDistance);
if (fraction > startFraction)
{
startFraction = fraction;
}
}
else
{
float fraction = (startDistance + Q3BSPConstants.Epsilon) / (startDistance - endDistance);
if (fraction < endFraction)
{
endFraction = fraction;
}
}
}
if (false == startsOut)
{
cd.startOutside = false;
if (false == endsOut)
{
cd.inSolid = true;
}
return;
}
if (startFraction < endFraction)
{
if (startFraction > -1.0f && startFraction < cd.ratio)
{
if (startFraction < 0)
{
startFraction = 0;
}
cd.ratio = startFraction;
}
}
}
private void WalkNode(int nodeIndex, float startRatio, float endRatio, Vector3 startPosition, Vector3 endPosition, ref Q3BSPCollisionData cd)
{
// Is this a leaf?
if (0 > nodeIndex)
{
Q3BSPLeaf leaf = leafs[-(nodeIndex + 1)];
for (int i = 0; i < leaf.LeafBrushCount; i++)
{
Q3BSPBrush brush = brushes[leafBrushes[leaf.StartLeafBrush + i]];
if (0 < brush.NumberOfSides &&
1 == (textureData[brush.TextureIndex].Contents & 1))
{
CheckBrush(ref brush, ref cd);
}
}
return;
}
// This is a node
Q3BSPNode thisNode = nodes[nodeIndex];
Plane thisPlane = planes[thisNode.Plane];
float startDistance = Vector3.Dot(startPosition, thisPlane.Normal) - thisPlane.D;
float endDistance = Vector3.Dot(endPosition, thisPlane.Normal) - thisPlane.D;
float offset = 0;
// Set offset for sphere-based collision
if (cd.type == Q3BSPCollisionType.Sphere)
{
offset = cd.sphereRadius;
}
// Set offest for box-based collision
if (cd.type == Q3BSPCollisionType.Box)
{
offset = Math.Abs(cd.boxExtents.X * thisPlane.Normal.X) + Math.Abs(cd.boxExtents.Y * thisPlane.Normal.Y) + Math.Abs(cd.boxExtents.Z * thisPlane.Normal.Z);
}
if (startDistance >= offset && endDistance >= offset)
{
// Both points are in front
WalkNode(thisNode.Left, startRatio, endRatio, startPosition, endPosition, ref cd);
}
else if (startDistance < -offset && endDistance < -offset)
{
WalkNode(thisNode.Right, startRatio, endRatio, startPosition, endPosition, ref cd);
}
else
{
// The line spans the splitting plane
int side = 0;
float fraction1 = 0.0f;
float fraction2 = 0.0f;
float middleFraction = 0.0f;
Vector3 middlePosition = new Vector3();
if (startDistance < endDistance)
{
side = 1;
float inverseDistance = 1.0f / (startDistance - endDistance);
fraction1 = (startDistance - offset + Q3BSPConstants.Epsilon) * inverseDistance;
fraction2 = (startDistance + offset + Q3BSPConstants.Epsilon) * inverseDistance;
}
else if (endDistance < startDistance)
{
side = 0;
float inverseDistance = 1.0f / (startDistance - endDistance);
fraction1 = (startDistance + offset + Q3BSPConstants.Epsilon) * inverseDistance;
fraction2 = (startDistance - offset - Q3BSPConstants.Epsilon) * inverseDistance;
}
else
{
side = 0;
fraction1 = 1.0f;
fraction2 = 0.0f;
}
if (fraction1 < 0.0f)
{
fraction1 = 0.0f;
}
else if (fraction1 > 1.0f)
{
fraction1 = 1.0f;
}
if (fraction2 < 0.0f)
{
fraction2 = 0.0f;
}
else if (fraction2 > 1.0f)
{
fraction2 = 1.0f;
}
middleFraction = startRatio + (endRatio - startRatio) * fraction1;
middlePosition = startPosition + fraction1 * (endPosition - startPosition);
int side1;
int side2;
if (0 == side)
{
side1 = thisNode.Left;
side2 = thisNode.Right;
}
else
{
side1 = thisNode.Right;
side2 = thisNode.Left;
}
WalkNode(side1, startRatio, middleFraction, startPosition, middlePosition, ref cd);
middleFraction = startRatio + (endRatio - startRatio) * fraction2;
middlePosition = startPosition + fraction2 * (endPosition - startPosition);
WalkNode(side2, middleFraction, endRatio, middlePosition, endPosition, ref cd);
}
}
