From 6fcf04a2984b8b813cc08f15a68b5ce7b61cb11a Mon Sep 17 00:00:00 2001
From: Eric Wasylishen <ewasylishen@gmail.com>
Date: Wed, 6 Apr 2016 19:15:19 -0600
Subject: [PATCH] light: revert to older CalcPoints (push off hit normal) to
 fix artifacts in testlightonface.map

---
 light/ltface.c        | 33 +++++++++++++++++++--------------
 light/trace_embree.cc |  4 +++-
 2 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/light/ltface.c b/light/ltface.c
index 0bc3aef7..b3d977a0 100644
--- a/light/ltface.c
+++ b/light/ltface.c
@@ -635,20 +635,25 @@ CalcPoints(const modelinfo_t *modelinfo, const vec3_t offset, const texorg_t *te
                 VectorCopy(surf->plane.normal, norm);
             }
 
-            vec3_t tracevec, tracedir;
-            VectorSubtract(point, surf->midpoint, tracevec);
-            VectorCopy(tracevec, tracedir);
-            VectorNormalize(tracedir);
-            
-            // trace 1 unit further than we need to go to ensure 1 unit clearance
-            const vec_t dist = VectorLength(tracevec) + 1;
-            
-            vec_t hitdist = 0;
-            vec3_t hitnormal = {0};
-            if (CalcPointsTrace_embree(surf->midpoint, tracedir, dist, &hitdist, hitnormal, surf->modelinfo)) {
-                // we hit a solid. pull back 1 unit from the hitpoint and hope that's in empty space.
-                hitdist = qmax(0.0f, hitdist - 1.0f);
-                VectorMA(surf->midpoint, hitdist, tracedir, point);
+            for (int tries=0; tries<5; tries++) {
+                vec3_t tracevec, tracedir;
+                VectorSubtract(point, surf->midpoint, tracevec);
+                VectorCopy(tracevec, tracedir);
+                VectorNormalize(tracedir);
+                
+                // trace 1 unit further than we need to go to ensure 1 unit clearance
+                const vec_t dist = VectorLength(tracevec) + 1;
+                
+                vec_t hitdist = 0;
+                vec3_t hitnormal = {0};
+                if (CalcPointsTrace_embree(surf->midpoint, tracedir, dist, &hitdist, hitnormal, surf->modelinfo)) {
+                    // we hit a solid. pull back 1 unit in the direction of the hit normal
+                    vec3_t hitpoint;
+                    VectorMA(surf->midpoint, hitdist, tracedir, hitpoint);
+                    VectorMA(hitpoint, 1, hitnormal, point);
+                } else {
+                    break;
+                }
             }
         }
     }
diff --git a/light/trace_embree.cc b/light/trace_embree.cc
index 8b1a4525..9c765670 100644
--- a/light/trace_embree.cc
+++ b/light/trace_embree.cc
@@ -329,8 +329,10 @@ CalcPointsTrace_embree(const vec3_t start, const vec3_t dir, vec_t dist, vec_t *
     
     if (hitdist)
         *hitdist = ray.tfar;
-    if (normal)
+    if (normal) {
         VectorCopy(ray.Ng, normal);
+        VectorNormalize(normal);
+    }
 
     return ray.geomID != RTC_INVALID_GEOMETRY_ID;
 }