protected virtual void ProcessNode(BspNode node, Ray tracingRay, float maxDistance, float traceDistance)
{
// check if ray already encountered a solid brush
if (StopRayTracing) return;
if (node.IsLeaf)
{
ProcessLeaf(node, tracingRay, maxDistance, traceDistance);
return;
}
IntersectResult result = tracingRay.Intersects(node.SplittingPlane);
if (result.Hit)
{
if (result.Distance < maxDistance)
{
if (node.GetSide(tracingRay.Origin) == PlaneSide.Negative)
{
ProcessNode(node.BackNode, tracingRay, result.Distance, traceDistance);
Vector3 splitPoint = tracingRay.Origin + tracingRay.Direction * result.Distance;
ProcessNode(node.FrontNode, new Ray(splitPoint, tracingRay.Direction), maxDistance - result.Distance, traceDistance + result.Distance);
}
else
{
ProcessNode(node.FrontNode, tracingRay, result.Distance, traceDistance);
Vector3 splitPoint = tracingRay.Origin + tracingRay.Direction * result.Distance;
ProcessNode(node.BackNode, new Ray(splitPoint, tracingRay.Direction), maxDistance - result.Distance, traceDistance + result.Distance);
}
}
else
ProcessNode(node.GetNextNode(tracingRay.Origin), tracingRay, maxDistance, traceDistance);
}
else
ProcessNode(node.GetNextNode(tracingRay.Origin), tracingRay, maxDistance, traceDistance);
}
public bool RayIntersection(Ray ray, out int x, out int z)
{
// generate a bounding box for the heightmap in its local space
AxisAlignedBox axisAlignedBox = new AxisAlignedBox(new Vector3(0, minHeight, 0),
new Vector3(width, maxHeight, height));
Vector3 rayLoc = new Vector3((ray.Origin.x - offsetX) / xzScale,
ray.Origin.y / yScale,
(ray.Origin.z - offsetZ) / xzScale);
Vector3 rayDir = new Vector3(ray.Direction.x / xzScale, ray.Direction.y / yScale, ray.Direction.z / xzScale);
rayDir.Normalize();
// convert the ray to local heightmap space
Ray tmpRay = new Ray(rayLoc, rayDir);
// see if the ray intersects with the bounding box
IntersectResult result = tmpRay.Intersects(axisAlignedBox);
if (result.Hit)
{
// move rayLoc up to just before the point of intersection
rayLoc = rayLoc + rayDir * ( result.Distance - 1 );
//
// deal with edge case where ray is coming from outside the heightmap
// and is very near edge of map at intersection.
//
int insideCounter = 20;
while ((!Inside(rayLoc)) && (insideCounter > 0))
{
rayLoc += ( rayDir * 0.1f );
insideCounter--;
}
if (insideCounter == 0)
{
x = 0;
z = 0;
return false;
}
x = (int)Math.Round(rayLoc.x);
z = (int)Math.Round(rayLoc.z);
if (x < 0)
{
x = 0;
}
if (x >= width)
{
x = width - 1;
}
if (z < 0)
{
z = 0;
}
if (z >= height)
{
z = height - 1;
}
bool above = rayLoc.y > heightData[x + z * width];
while (Inside(rayLoc))
{
// increment the ray
rayLoc += rayDir;
x = (int)Math.Round(rayLoc.x);
z = (int)Math.Round(rayLoc.z);
if (x < 0)
{
x = 0;
}
if (x >= width)
{
x = width - 1;
}
if (z < 0)
{
z = 0;
}
if (z >= height)
{
z = height - 1;
}
if (above != (rayLoc.y > heightData[x + z * width]))
{
// we found a hit
return true;
}
}
}
x = 0;
z = 0;
return false;
}
protected virtual void ProcessLeaf(BspNode leaf, Ray tracingRay, float maxDistance, float traceDistance)
{
MovableObjectCollection objects = leaf.Objects;
int numObjects = objects.Count;
//Check ray against objects
for(int a = 0; a < numObjects; a++)
{
MovableObject obj = objects[a];
// Skip this object if collision not enabled
if((obj.QueryFlags & queryMask) == 0)
continue;
//Test object as bounding box
IntersectResult result = tracingRay.Intersects(obj.GetWorldBoundingBox());
// if the result came back positive and intersection point is inside
// the node, fire the event handler
if(result.Hit && result.Distance <= maxDistance)
{
listener.OnQueryResult(obj, result.Distance + traceDistance);
}
}
PlaneBoundedVolume boundedVolume = new PlaneBoundedVolume(PlaneSide.Positive);
BspBrush intersectBrush = null;
float intersectBrushDist = float.PositiveInfinity;
// Check ray against brushes
for (int brushPoint=0; brushPoint < leaf.SolidBrushes.Length; brushPoint++)
{
BspBrush brush = leaf.SolidBrushes[brushPoint];
if (brush == null) continue;
boundedVolume.planes = brush.Planes;
IntersectResult result = tracingRay.Intersects(boundedVolume);
// if the result came back positive and intersection point is inside
// the node, check if this brush is closer
if(result.Hit && result.Distance <= maxDistance)
{
if (result.Distance < intersectBrushDist)
{
intersectBrushDist = result.Distance;
intersectBrush = brush;
}
}
}
if (intersectBrush != null)
{
listener.OnQueryResult(intersectBrush.Fragment, intersectBrushDist + traceDistance);
StopRayTracing = true;
}
}