public void intersect(Ray r, IntersectionState state)
{
float intervalMin = r.getMin();
float intervalMax = r.getMax();
float orgX = r.ox;
float dirX = r.dx, invDirX = 1 / dirX;
float t1, t2;
t1 = (bounds.getMinimum().x - orgX) * invDirX;
t2 = (bounds.getMaximum().x - orgX) * invDirX;
if (invDirX > 0)
{
if (t1 > intervalMin)
{
intervalMin = t1;
}
if (t2 < intervalMax)
{
intervalMax = t2;
}
}
else
{
if (t2 > intervalMin)
{
intervalMin = t2;
}
if (t1 < intervalMax)
{
intervalMax = t1;
}
}
if (intervalMin > intervalMax)
{
return;
}
float orgY = r.oy;
float dirY = r.dy, invDirY = 1 / dirY;
t1 = (bounds.getMinimum().y - orgY) * invDirY;
t2 = (bounds.getMaximum().y - orgY) * invDirY;
if (invDirY > 0)
{
if (t1 > intervalMin)
{
intervalMin = t1;
}
if (t2 < intervalMax)
{
intervalMax = t2;
}
}
else
{
if (t2 > intervalMin)
{
intervalMin = t2;
}
if (t1 < intervalMax)
{
intervalMax = t1;
}
}
if (intervalMin > intervalMax)
{
return;
}
float orgZ = r.oz;
float dirZ = r.dz, invDirZ = 1 / dirZ;
t1 = (bounds.getMinimum().z - orgZ) * invDirZ;
t2 = (bounds.getMaximum().z - orgZ) * invDirZ;
if (invDirZ > 0)
{
if (t1 > intervalMin)
{
intervalMin = t1;
}
if (t2 < intervalMax)
{
intervalMax = t2;
}
}
else
{
if (t2 > intervalMin)
{
intervalMin = t2;
}
if (t1 < intervalMax)
{
intervalMax = t1;
}
}
if (intervalMin > intervalMax)
{
return;
}
// box is hit at [intervalMin, intervalMax]
orgX += intervalMin * dirX;
orgY += intervalMin * dirY;
orgZ += intervalMin * dirZ;
// locate starting point inside the grid
// and set up 3D-DDA vars
int indxX, indxY, indxZ;
int stepX, stepY, stepZ;
int stopX, stopY, stopZ;
float deltaX, deltaY, deltaZ;
float tnextX, tnextY, tnextZ;
// stepping factors along X
indxX = (int)((orgX - bounds.getMinimum().x) * invVoxelwx);
if (indxX < 0)
{
indxX = 0;
}
else if (indxX >= nx)
{
indxX = nx - 1;
}
if (Math.Abs(dirX) < 1e-6f)
{
stepX = 0;
stopX = indxX;
deltaX = 0;
tnextX = float.PositiveInfinity;
}
else if (dirX > 0)
{
stepX = 1;
stopX = nx;
deltaX = voxelwx * invDirX;
tnextX = intervalMin + ((indxX + 1) * voxelwx + bounds.getMinimum().x - orgX) * invDirX;
}
else
{
stepX = -1;
stopX = -1;
deltaX = -voxelwx * invDirX;
tnextX = intervalMin + (indxX * voxelwx + bounds.getMinimum().x - orgX) * invDirX;
}
// stepping factors along Y
indxY = (int)((orgY - bounds.getMinimum().y) * invVoxelwy);
if (indxY < 0)
{
indxY = 0;
}
else if (indxY >= ny)
{
indxY = ny - 1;
}
if (Math.Abs(dirY) < 1e-6f)
{
stepY = 0;
stopY = indxY;
deltaY = 0;
tnextY = float.PositiveInfinity;
}
else if (dirY > 0)
{
stepY = 1;
stopY = ny;
deltaY = voxelwy * invDirY;
tnextY = intervalMin + ((indxY + 1) * voxelwy + bounds.getMinimum().y - orgY) * invDirY;
}
else
{
stepY = -1;
stopY = -1;
deltaY = -voxelwy * invDirY;
tnextY = intervalMin + (indxY * voxelwy + bounds.getMinimum().y - orgY) * invDirY;
}
// stepping factors along Z
indxZ = (int)((orgZ - bounds.getMinimum().z) * invVoxelwz);
if (indxZ < 0)
{
indxZ = 0;
}
else if (indxZ >= nz)
{
indxZ = nz - 1;
}
if (Math.Abs(dirZ) < 1e-6f)
{
stepZ = 0;
stopZ = indxZ;
deltaZ = 0;
tnextZ = float.PositiveInfinity;
}
else if (dirZ > 0)
{
stepZ = 1;
stopZ = nz;
deltaZ = voxelwz * invDirZ;
tnextZ = intervalMin + ((indxZ + 1) * voxelwz + bounds.getMinimum().z - orgZ) * invDirZ;
}
else
{
stepZ = -1;
stopZ = -1;
deltaZ = -voxelwz * invDirZ;
tnextZ = intervalMin + (indxZ * voxelwz + bounds.getMinimum().z - orgZ) * invDirZ;
}
int cellstepX = stepX;
int cellstepY = stepY * nx;
int cellstepZ = stepZ * ny * nx;
int cell = indxX + indxY * nx + indxZ * ny * nx;
// trace through the grid
for (; ;)
{
if (tnextX < tnextY && tnextX < tnextZ)
{
if (cells[cell] != null)
{
foreach (int i in cells[cell])
{
primitives.intersectPrimitive(r, i, state);
}
if (state.hit() && (r.getMax() < tnextX && r.getMax() < intervalMax))
{
return;
}
}
intervalMin = tnextX;
if (intervalMin > intervalMax)
{
return;
}
indxX += stepX;
if (indxX == stopX)
{
return;
}
tnextX += deltaX;
cell += cellstepX;
}
else if (tnextY < tnextZ)
{
if (cells[cell] != null)
{
foreach (int i in cells[cell])
{
primitives.intersectPrimitive(r, i, state);
}
if (state.hit() && (r.getMax() < tnextY && r.getMax() < intervalMax))
{
return;
}
}
intervalMin = tnextY;
if (intervalMin > intervalMax)
{
return;
}
indxY += stepY;
if (indxY == stopY)
{
return;
}
tnextY += deltaY;
cell += cellstepY;
}
else
{
if (cells[cell] != null)
{
foreach (int i in cells[cell])
{
primitives.intersectPrimitive(r, i, state);
}
if (state.hit() && (r.getMax() < tnextZ && r.getMax() < intervalMax))
{
return;
}
}
intervalMin = tnextZ;
if (intervalMin > intervalMax)
{
return;
}
indxZ += stepZ;
if (indxZ == stopZ)
{
return;
}
tnextZ += deltaZ;
cell += cellstepZ;
}
}
}
