Revert "light: move Lightmap_Soften into WriteLightmaps"

This reverts commit bc2d734e9a.

include/light/light.hh

@@ -190,7 +190,7 @@ extern int numDirtVectors;
 extern bool dirt_in_use;               // should any dirtmapping take place? set in SetupDirt
 
 extern float fadegate;
-extern int softsamples; // this many samples away from the reference sample are averaged. basically filter radius.
+extern int softsamples;
 extern const vec3_t vec3_white;
 extern float surflight_subdivide;
 extern int sunsamples;

light/light.cc

@@ -1076,7 +1076,7 @@ light_main(int argc, const char **argv)
             softsamples = 1;
             break;
         case 4:
-            softsamples = 1;
+            softsamples = 2;
             break;
         default:
             softsamples = 0;

light/ltface.cc

@@ -880,6 +880,55 @@ Lightmap_Save(lightmapdict_t *lightmaps, const lightsurf_t *lightsurf,
     }
 }
 
+/*
+ * Average adjacent points on the grid to soften shadow edges
+ */
+static void
+Lightmap_Soften(lightmap_t *lightmap, const lightsurf_t *lightsurf)
+{
+    const int width = (lightsurf->texsize[0] + 1) * oversample;
+    const int height = (lightsurf->texsize[1] + 1) * oversample;
+    const int fullsamples = (2 * softsamples + 1) * (2 * softsamples + 1);
+
+    lightsample_t *softmap = (lightsample_t *) calloc(lightsurf->numpoints, sizeof(lightsample_t));
+    
+    lightsample_t *dst = softmap;
+    for (int i = 0; i < lightsurf->numpoints; i++, dst++) {
+        const int startt = qmax((i / width) - softsamples, 0);
+        const int endt = qmin((i / width) + softsamples + 1, height);
+        const int starts = qmax((i % width) - softsamples, 0);
+        const int ends = qmin((i % width) + softsamples + 1, width);
+
+        for (int t = startt; t < endt; t++) {
+            for (int s = starts; s < ends; s++) {
+                const lightsample_t *src = &lightmap->samples[t * width + s];
+                VectorAdd(dst->color, src->color, dst->color);
+                VectorAdd(dst->direction, src->direction, dst->direction);
+            }
+        }
+        /*
+         * For cases where we are softening near the edge of the lightmap,
+         * take extra samples from the centre point (follows old bjp tools
+         * behaviour)
+         */
+        int samples = (endt - startt) * (ends - starts);
+        if (samples < fullsamples) {
+            const int extraweight = 2 * (fullsamples - samples);
+            const lightsample_t *src = &lightmap->samples[i];
+            VectorMA(dst->color, extraweight, src->color, dst->color);
+            VectorMA(dst->direction, extraweight, src->direction, dst->direction);
+            samples += extraweight;
+        }
+        VectorScale(dst->color, 1.0 / samples, dst->color);
+        VectorScale(dst->direction, 1.0 / samples, dst->direction);
+    }
+
+    memcpy(lightmap->samples, softmap, lightsurf->numpoints * sizeof(lightsample_t));
+    free(softmap);
+}
+
+
+
 /*
  * ============================================================================
  * FACE LIGHTING
@@ -2621,5 +2670,12 @@ LightFace(bsp2_dface_t *face, facesup_t *facesup, const modelinfo_t *modelinfo,
     /* Apply gamma, rangescale, and clamp */
     LightFace_ScaleAndClamp(lightsurf, lightmaps);
     
+    /* Perform post-processing if requested */
+    if (softsamples > 0) {
+        for (lightmap_t &lightmap : *lightmaps) {
+            Lightmap_Soften(&lightmap, lightsurf);
+        }
+    }
+    
     WriteLightmaps(bsp, face, facesup, lightsurf, lightmaps);
 }