htsky

commit bbc29781f3007b7927f854b1a898ee8e73371a41
parent a5e432778f4d5832e04088cfca3ab262ae8d240e
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Thu, 16 Apr 2020 21:42:34 +0200

Fix an issue in the world_to_cloud routine

The upper bound of the cloud was inclusive while it must not be.

Diffstat:
M
src/htsky.c
 | 
13
+++++++++----

1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/src/htsky.c b/src/htsky.c
@@ -997,6 +997,7 @@ world_to_cloud
    double out_pos_cs[3])
 {
   double cloud_sz[2];
+  double upper[2];
   double pos_cs[3];
   double pos_cs_n[2];
   ASSERT(sky && pos_ws && out_pos_cs);
@@ -1015,14 +1016,18 @@ world_to_cloud
     return d3_set(out_pos_cs, pos_ws);
   }
 
-  cloud_sz[0] = sky->htcp_desc.upper[0] - sky->htcp_desc.lower[0];
-  cloud_sz[1] = sky->htcp_desc.upper[1] - sky->htcp_desc.lower[1];
+  /* The cloud upper bound is not inclusive. Define the inclusive upper bound
+   * of the cloud */
+  upper[0] = nextafter(sky->htcp_desc.upper[0], sky->htcp_desc.lower[0]);
+  upper[1] = nextafter(sky->htcp_desc.upper[1], sky->htcp_desc.lower[1]);
+  cloud_sz[0] = upper[0] - sky->htcp_desc.lower[0];
+  cloud_sz[1] = upper[1] - sky->htcp_desc.lower[1];
 
   /* Transform pos in normalize local cloud space */
   pos_cs_n[0] = (pos_ws[0] - sky->htcp_desc.lower[0]) / cloud_sz[0];
   pos_cs_n[1] = (pos_ws[1] - sky->htcp_desc.lower[1]) / cloud_sz[1];
-  pos_cs_n[0] -= (int)pos_cs_n[0]; /* Keep fractional part */
-  pos_cs_n[1] -= (int)pos_cs_n[1]; /* Keep fractional part */
+  pos_cs_n[0] -= (int)pos_cs_n[0]; /* Get fractional part */
+  pos_cs_n[1] -= (int)pos_cs_n[1]; /* Get fractional part */
   if(pos_cs_n[0] < 0) pos_cs_n[0] += 1;
   if(pos_cs_n[1] < 0) pos_cs_n[1] += 1;