qbsp, light: allow _minlight to go up to 510 instead of 255 on func_detail/etc.

include/common/bspfile.hh

@@ -457,10 +457,14 @@ struct surfflags_t {
     // if non zero, enables phong shading and gives the angle threshold to use
     uint8_t phong_angle;
 
-    // minlight value for this face
+    // minlight value for this face, multiplied by 0.5, so we can store overbrights in 8 bits
+    // FIXME: skip the compression and just store a float? serialize all of these to a JSON .texinfo
+    // for better extensibility?
     uint8_t minlight;
 
     // red minlight colors for this face
+    // FIXME: this probably makes it illegal to memcpy() from a surfflags_t, which is done in
+    // WriteExtendedTexinfoFlags. Again, points to switching to JSON serialization.
     std::array<uint8_t, 3> minlight_color;
     
     // if non zero, overrides _phong_angle for concave joints

light/ltface.cc

@@ -781,7 +781,7 @@ Lightsurf_Init(const modelinfo_t *modelinfo, const bsp2_dface_t *face,
     if (modelinfo->minlight.isChanged()) {
         lightsurf->minlight = modelinfo->minlight.floatValue();
     } else {
-        lightsurf->minlight = extended_flags.minlight;
+        lightsurf->minlight = (float)extended_flags.minlight * 2; // see SurfFlagsForEntity
     }
     
     // minlight_color

qbsp/map.cc

@@ -450,7 +450,7 @@ SurfFlagsForEntity(const mtexinfo_t &texinfo, const mapentity_t *entity)
     // handle "_minlight"
     const vec_t minlight = atof(ValueForKey(entity, "_minlight"));
     if (minlight > 0) {
-        flags.minlight = qclamp((int)rint(minlight), 0, 255);
+        flags.minlight = qclamp((int)rint(minlight), 0, 510) / 2; // map 0..510 to 0..255, so we can handle overbright
     }
 
     // handle "_mincolor"