# HG changeset patch
# User Matthew Turk <matthewturk@gmail.com>
# Date 1247597349 14400
# Branch raytrace
# Node ID 547d886e82642901ebf83274f14bb69c06184fc6
# Parent  b2a83377938656c37e9f0fd6fee1be44e94d47ee
This works for random points, but fails for cell-edges.

diff -r b2a83377938656c37e9f0fd6fee1be44e94d47ee -r 547d886e82642901ebf83274f14bb69c06184fc6 yt/lagos/RTIntegrator.pyx
--- a/yt/lagos/RTIntegrator.pyx	Mon Jul 13 09:33:11 2009 -0700
+++ b/yt/lagos/RTIntegrator.pyx	Tue Jul 14 14:49:09 2009 -0400
@@ -115,9 +115,11 @@
     # Now get the indices of the intersection
     intersect = u + intersect_t * v
     for i in range(3):
-        cur_ind[i] = np.floor((intersect[i] - left_edge[i])/dx[i])
+        cur_ind[i] = min(np.floor((intersect[i] - left_edge[i])/dx[i]),
+                         grid_mask.shape[i] - 1)
         tmax[i] = (((cur_ind[i]+step[i])*dx[i])+left_edge[i]-u[i])/v[i]
-        if step[i] < 0: cur_ind[i] -= 1
+        if step[i] > 0: tmax[i] = (((cur_ind[i]+1)*dx[i])+left_edge[i]-u[i])/v[i]
+        if step[i] < 0: tmax[i] = (((cur_ind[i]+0)*dx[i])+left_edge[i]-u[i])/v[i]
         tdelta[i] = abs(dx[i]/v[i])
     # The variable intersect contains the point we first pierce the grid
     enter_t = intersect_t
@@ -132,7 +134,7 @@
         # Note that we are calculating t on the fly, but we get *negative* t
         # values from what they should be.
         # If we've reached t = 1, we are done.
-        if tmax[0] >= 1 and tmax[1] >= 1 and tmax[2] >= 1:
+        if (tmax[0] >= 1.0) and (tmax[1] >= 1.0) and (tmax[2] >= 1.0):
             grid_t[cur_ind[0], cur_ind[1], cur_ind[2]] = 1.0 - enter_t
             break
         if tmax[0] < tmax[1]: