private void CheckBrush(ref Q3Brush brush, ref Q3CollisionData cd)
{
float startFraction = -1.0f;
float endFraction = 1.0f;
bool startsOut = false;
bool endsOut = false;
for (int i = 0; i < brush.NumSides; i++)
{
Q3BrushSide brushSide = m_brushSides[brush.FirstSide + i];
Q3Plane plane = m_planes[brushSide.PlaneNum];
float startDistance = 0, endDistance = 0;
if (cd.type == Q3CollisionType.Ray)
{
startDistance = cd.startPosition.Dot(new Vector3( plane.Normal) ) - plane.Distance;
endDistance = cd.endPosition.Dot(new Vector3(plane.Normal) ) - plane.Distance;
}
else if (cd.type == Q3CollisionType.Sphere)
{
startDistance = cd.startPosition.Dot(new Vector3( plane.Normal)) - (plane.Distance + cd.sphereRadius);
endDistance = cd.endPosition.Dot(new Vector3( plane.Normal)) - (plane.Distance + cd.sphereRadius);
}
else if (cd.type == Q3CollisionType.Box)
{
Vector3 offset = new Vector3();
if ((new Vector3(plane.Normal)).X < 0)
offset.X = cd.boxMaximums.X;
else
offset.X = cd.boxMinimums.X;
if ((new Vector3(plane.Normal)).Y < 0)
offset.Y = cd.boxMaximums.Y;
else
offset.Y = cd.boxMinimums.Y;
if ((new Vector3(plane.Normal)).Z < 0)
offset.Z = cd.boxMaximums.Z;
else
offset.Z = cd.boxMinimums.Z;
startDistance = (cd.startPosition.X + offset.X) * (new Vector3(plane.Normal)).X +
(cd.startPosition.Y + offset.Y) * (new Vector3(plane.Normal)).Y +
(cd.startPosition.Z + offset.Z) * (new Vector3(plane.Normal)).Z -
plane.Distance;
endDistance = (cd.endPosition.X + offset.X) * (new Vector3(plane.Normal)).X +
(cd.endPosition.Y + offset.Y) * (new Vector3(plane.Normal)).Y +
(cd.endPosition.Z + offset.Z) * (new Vector3(plane.Normal)).Z -
plane.Distance;
}
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 - Q3Constants.Epsilon) / (startDistance - endDistance);
if (fraction > startFraction)
startFraction = fraction;
}
else
{
float fraction = (startDistance + Q3Constants.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;
}
}
}
public Q3CollisionData TraceSphere(Vector3 startPosition, Vector3 endPosition, float sphereRadius)
{
Q3CollisionData collision = new Q3CollisionData();
collision.type = Q3CollisionType.Sphere;
collision.sphereRadius = sphereRadius;
return Trace(startPosition, endPosition, ref collision);
}
public Q3CollisionData TraceRay(Vector3 startPosition, Vector3 endPosition)
{
Q3CollisionData collision = new Q3CollisionData();
collision.type = Q3CollisionType.Ray;
return Trace(startPosition, endPosition, ref collision);
}
public Q3CollisionData TraceBox(Vector3 startPosition, Vector3 endPosition, AABB bbox)
{
Q3CollisionData collision = new Q3CollisionData();
Vector3 boxMinimums = bbox.Min;
Vector3 boxMaximums = bbox.Max;
if (boxMinimums.X == 0 && boxMinimums.Y == 0 && boxMinimums.Z == 0 && boxMaximums.X == 0 && boxMaximums.Y == 0 && boxMaximums.Z == 0)
{
collision.type = Q3CollisionType.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 = Q3CollisionType.Box;
collision.boxMinimums = boxMinimums;
collision.boxMaximums = boxMaximums;
collision.boxExtents = boxExtents;
return Trace(startPosition, endPosition, ref collision);
}
private void WalkNode(int nodeIndex, float startRatio, float endRatio, Vector3 startPosition, Vector3 endPosition, ref Q3CollisionData cd)
{
// Is this a leaf?
if (0 > nodeIndex)
{
Q3Leaf leaf = m_leaves[~nodeIndex];
for (int i = 0; i < leaf.BrushCount; i++)
{
Q3Brush brush = m_brushes[m_leafBrushes[leaf.BrushStart + i]];
if (0 < brush.NumSides &&
1 == ((int)m_shaders[brush.ShaderIndex].ContentFlags & 1))
{
CheckBrush(ref brush, ref cd);
}
}
return;
}
// This is a node
Q3Node thisNode = m_nodes[nodeIndex];
Q3Plane thisPlane = m_planes[thisNode.Plane];
float startDistance = startPosition.Dot( new Vector3(thisPlane.Normal) ) - thisPlane.Distance;
float endDistance = endPosition.Dot( new Vector3(thisPlane.Normal) ) - thisPlane.Distance;
float offset = 0;
// Set offset for sphere-based collision
if (cd.type == Q3CollisionType.Sphere)
{
offset = cd.sphereRadius;
}
// Set offest for box-based collision
if (cd.type == Q3CollisionType.Box)
{
offset = Math.Abs(cd.boxExtents.X * (new Vector3(thisPlane.Normal)).X) + Math.Abs(cd.boxExtents.Y * (new Vector3(thisPlane.Normal)).Y) + Math.Abs(cd.boxExtents.Z * (new Vector3(thisPlane.Normal)).Z);
}
if (startDistance >= offset && endDistance >= offset)
{
// Both points are in front
WalkNode(thisNode.Front, startRatio, endRatio, startPosition, endPosition, ref cd);
}
else if (startDistance < -offset && endDistance < -offset)
{
WalkNode(thisNode.Back, 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 + Q3Constants.Epsilon) * inverseDistance;
fraction2 = (startDistance + offset + Q3Constants.Epsilon) * inverseDistance;
}
else if (endDistance < startDistance)
{
side = 0;
float inverseDistance = 1.0f / (startDistance - endDistance);
fraction1 = (startDistance + offset + Q3Constants.Epsilon) * inverseDistance;
fraction2 = (startDistance - offset - Q3Constants.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.Front;
side2 = thisNode.Back;
}
else
{
side1 = thisNode.Back;
side2 = thisNode.Front;
}
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);
}
}
private Q3CollisionData Trace(Vector3 startPosition, Vector3 endPosition, ref Q3CollisionData 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;
}
