public IntersectionData()
{
hitT = double.MaxValue;
hitPos = new Vector3();
hitNormal = new Vector3();
hitUV = new Vector3();
hitPrimitive = null;
hasIntersection = false;
textureUVW = new Vector3();
shaderID = 0;
}
public void GetIntersection(
Vector3 rayOrigin, Vector3 rayDirection, GeomPrimitive lastHit,
out GeomPrimitive pHitObject, Vector3 pStart, RayContext rayContext)
{
//hitPosition = null;
pHitObject = null;
// is branch: step through subcells and recurse
if (isBranch)
{
//if (pStart == null)
// pStart = rayOrigin;
// find which subcell holds ray origin (ray origin is inside cell)
int subCell = 0;
for (int i = 3; i-- > 0; )
{
// compare dimension with center
if (pStart[i] >= ((bound[i] + bound[i + 3]) * 0.5f))
subCell |= 1 << i;
}
// step through intersected subcells
Vector3 cellPosition = new Vector3(pStart);
for (; ; )
{
if (null != spatial[subCell])
{
// intersect subcell
spatial[subCell].GetIntersection(rayOrigin, rayDirection, lastHit, out pHitObject, cellPosition, rayContext);
// exit if item hit
if (null != pHitObject)
break;
}
// find next subcell ray moves to
// (by finding which face of the corner ahead is crossed first)
int axis = 2;
float[] step = new float[3]; // todo - move this allocation?
for (int i = 3; i-- > 0; axis = step[i] < step[axis] ? i : axis)
{
bool high = ((subCell >> i) & 1) != 0;
float face = (rayDirection[i] < 0.0f) ^ high ? bound[i + ((high ? 1 : 0) * 3)] : (bound[i] + bound[i + 3]) * 0.5f;
// distance to face
// (div by zero produces infinity, which is later discarded)
step[i] = (float)(face - rayOrigin[i]) / (float)rayDirection[i];
}
// leaving branch if: subcell is low and direction is negative,
// or subcell is high and direction is positive
if ((((subCell >> axis) & 1) != 0) ^ (rayDirection[axis] < 0.0f))
break;
// move to (outer face of) next subcell
cellPosition = rayOrigin + (rayDirection * step[axis]);
subCell = subCell ^ (1 << axis);
}
}
else
{ // is leaf: exhaustively intersect contained items
//float nearestDistance = float.MaxValue;
// step through items
foreach (GeomPrimitive item in triangles)
{
if (rayContext.ignorePrimitive == item)
continue; //skip this primitive
if (item == lastHit)
continue; //skip this primitive
IntersectionData hitData = new IntersectionData();
if (item.intersect(rayContext.ray, hitData))
{
// check intersection is inside cell bound (with tolerance)
Vector3 hit = rayOrigin + (rayDirection * hitData.hitT);
float t = TOLERANCE;
if ((bound[0] - hit[0] <= t) && (hit[0] - bound[3] <= t) &&
(bound[1] - hit[1] <= t) && (hit[1] - bound[4] <= t) &&
(bound[2] - hit[2] <= t) && (hit[2] - bound[5] <= t))
{
pHitObject = item;
//nearestDistance = distance;
//hitPosition = hit;
rayContext.hitData = hitData;
rayContext.hitData.hitPrimitive = item;
rayContext.hitData.hitPos = rayContext.ray.p + rayContext.ray.dir * rayContext.hitData.hitT;
rayContext.hitData.hasIntersection = true;
}
}
}
}
}
public void removePrimitive(GeomPrimitive primitive)
{
primitives.Remove(primitive);
}
public void addPrimitive(GeomPrimitive primitive)
{
primitives.Add(primitive);
}