light: make "_light_alpha 0" behave as expected (invisible to light)

include/common/bspfile.hh

@@ -208,7 +208,7 @@ struct surfflags_t
     qvec3b minlight_color;
 
     // custom opacity
-    vec_t light_alpha;
+    std::optional<vec_t> light_alpha;
 
     // maxlight value for this face
     vec_t maxlight;

light/trace_embree.cc

@@ -67,9 +67,8 @@ static float Face_Alpha(const mbsp_t *bsp, const modelinfo_t *modelinfo, const m
     const int surf_flags = Face_ContentsOrSurfaceFlags(bsp, face);
     const bool is_q2 = bsp->loadversion->game->id == GAME_QUAKE_II;
 
-    // for "_light_alpha", 0 is considered unset
     if (extended_flags.light_alpha) {
-        return extended_flags.light_alpha;
+        return *extended_flags.light_alpha;
     }
 
     // next check "alpha" key (q1)

qbsp/map.cc

@@ -680,8 +680,8 @@ static surfflags_t SurfFlagsForEntity(const maptexinfo_t &texinfo, const mapenti
     }
 
     // handle "_light_alpha"
+    if (entity.epairs.has("_light_alpha")) {
         const vec_t lightalpha = entity.epairs.get_float("_light_alpha");
-    if (lightalpha != 0.0) {
         flags.light_alpha = clamp(lightalpha, 0.0, 1.0);
     }
 

qbsp/writebsp.cc

@@ -393,7 +393,7 @@ static void WriteExtendedTexinfoFlags(void)
             t["minlight_color"] = tx.flags.minlight_color;
         }
         if (tx.flags.light_alpha) {
-            t["light_alpha"] = tx.flags.light_alpha;
+            t["light_alpha"] = *tx.flags.light_alpha;
         }
         if (tx.flags.lightcolorscale != 1.0) {
             t["lightcolorscale"] = tx.flags.lightcolorscale;

testmaps/q2_light_translucency.map

@@ -9,7 +9,7 @@
 "_tb_def" "builtin:Quake2.fgd"
 // brush 0
 {
-( -160 -256 16 ) ( -160 -255 16 ) ( -160 -256 17 ) e1u1/floor1_1 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( -768 -256 16 ) ( -768 -255 16 ) ( -768 -256 17 ) e1u1/floor1_1 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
 ( 80 -384 16 ) ( 80 -384 17 ) ( 81 -384 16 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
 ( 80 -256 16 ) ( 81 -256 16 ) ( 80 -255 16 ) e1u1/floor1_1 [ -1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
 ( 496 -32 32 ) ( 496 -31 32 ) ( 497 -32 32 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
@@ -18,7 +18,7 @@
 }
 // brush 1
 {
-( -160 -384 32 ) ( -160 -383 32 ) ( -160 -384 33 ) e1u1/floor1_1 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( -768 -384 32 ) ( -768 -383 32 ) ( -768 -384 33 ) e1u1/floor1_1 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
 ( -160 -384 32 ) ( -160 -384 33 ) ( -159 -384 32 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
 ( -160 -384 32 ) ( -159 -384 32 ) ( -160 -383 32 ) e1u1/floor1_1 [ -1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
 ( 256 -320 288 ) ( 256 -319 288 ) ( 257 -320 288 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
@@ -27,7 +27,7 @@
 }
 // brush 2
 {
-( -160 304 32 ) ( -160 305 32 ) ( -160 304 33 ) e1u1/floor1_1 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( -768 304 32 ) ( -768 305 32 ) ( -768 304 33 ) e1u1/floor1_1 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
 ( -160 304 32 ) ( -160 304 33 ) ( -159 304 32 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
 ( -160 304 32 ) ( -159 304 32 ) ( -160 305 32 ) e1u1/floor1_1 [ -1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
 ( 256 368 288 ) ( 256 369 288 ) ( 257 368 288 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
@@ -40,12 +40,12 @@
 ( -784 -320 32 ) ( -784 -320 33 ) ( -783 -320 32 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
 ( -784 240 32 ) ( -783 240 32 ) ( -784 241 32 ) e1u1/floor1_1 [ -1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
 ( -368 304 288 ) ( -368 305 288 ) ( -367 304 288 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
-( -368 304 48 ) ( -367 304 48 ) ( -368 304 49 ) e1u1/floor1_1 [ -1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( -368 192 48 ) ( -367 192 48 ) ( -368 192 49 ) e1u1/floor1_1 [ -1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
 ( -128 304 48 ) ( -128 304 49 ) ( -128 305 48 ) e1u1/floor1_1 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1
 }
 // brush 4
 {
-( -160 -256 288 ) ( -160 -255 288 ) ( -160 -256 289 ) e1u1/floor1_1 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( -768 -256 288 ) ( -768 -255 288 ) ( -768 -256 289 ) e1u1/floor1_1 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
 ( 80 -320 288 ) ( 80 -320 289 ) ( 81 -320 288 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
 ( 80 -256 288 ) ( 81 -256 288 ) ( 80 -255 288 ) e1u1/floor1_1 [ -1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
 ( 496 -32 304 ) ( 496 -31 304 ) ( 497 -32 304 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
@@ -70,12 +70,48 @@
 ( 336 0 184 ) ( 337 0 184 ) ( 336 0 185 ) e1u1/skip [ 1.0000000000000002 0 0 0 ] [ 0 0 -1.0000000000000002 16 ] 0 1 1 32 128 0
 ( 256 48 184 ) ( 256 48 185 ) ( 256 49 184 ) e1u1/skip [ 0 -1 0 0 ] [ 0 0 -1 16 ] 0 1 1 32 128 0
 }
+// brush 7
+{
+( -800 240 32 ) ( -800 241 32 ) ( -800 240 33 ) e1u1/floor1_1 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( -1424 -320 32 ) ( -1424 -320 33 ) ( -1423 -320 32 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( -1424 240 32 ) ( -1423 240 32 ) ( -1424 241 32 ) e1u1/floor1_1 [ -1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
+( -1008 304 288 ) ( -1008 305 288 ) ( -1007 304 288 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
+( -1008 320 48 ) ( -1007 320 48 ) ( -1008 320 49 ) e1u1/floor1_1 [ -1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( -768 304 48 ) ( -768 304 49 ) ( -768 305 48 ) e1u1/floor1_1 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+}
+// brush 8
+{
+( -448 240 32 ) ( -448 241 32 ) ( -448 240 33 ) e1u1/floor1_1 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( -1072 -320 32 ) ( -1072 -320 33 ) ( -1071 -320 32 ) e1u1/floor1_1 [ 1 0 0 32 ] [ 0 0 -1 0 ] 0 1 1
+( -1072 240 32 ) ( -1071 240 32 ) ( -1072 241 32 ) e1u1/floor1_1 [ -1 0 0 -32 ] [ 0 -1 0 0 ] 0 1 1
+( -656 304 288 ) ( -656 305 288 ) ( -655 304 288 ) e1u1/floor1_1 [ 1 0 0 32 ] [ 0 -1 0 0 ] 0 1 1
+( -656 32 48 ) ( -655 32 48 ) ( -656 32 49 ) e1u1/floor1_1 [ -1 0 0 -32 ] [ 0 0 -1 0 ] 0 1 1
+( -416 304 48 ) ( -416 304 49 ) ( -416 305 48 ) e1u1/floor1_1 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+}
+// brush 9
+{
+( -640 -112 32 ) ( -640 -111 32 ) ( -640 -112 33 ) e1u1/floor1_1 [ 0 0 -1.0000000000000002 -32 ] [ 0 -1.0000000000000002 0 0 ] 0 1 1
+( -640 -112 32 ) ( -640 -112 33 ) ( -639 -112 32 ) e1u1/floor1_1 [ 1.0000000000000002 0 0 0 ] [ 0 0 1.0000000000000002 16 ] 0 1 1
+( -640 -112 32 ) ( -639 -112 32 ) ( -640 -111 32 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
+( -576 -64 40 ) ( -576 -63 40 ) ( -575 -64 40 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
+( -576 -64 40 ) ( -575 -64 40 ) ( -576 -64 41 ) e1u1/floor1_1 [ 1.0000000000000002 0 0 0 ] [ 0 0 -1.0000000000000002 -32 ] 0 1 1
+( -576 -64 40 ) ( -576 -64 41 ) ( -576 -63 40 ) e1u1/floor1_1 [ 0 0 1.0000000000000002 32 ] [ 0 -1.0000000000000002 0 0 ] 0 1 1
+}
+// brush 10
+{
+( -320 -112 32 ) ( -320 -111 32 ) ( -320 -112 33 ) e1u1/floor1_1 [ 0 0 -1.0000000000000002 -32 ] [ 0 -1.0000000000000002 0 0 ] 0 1 1
+( -320 -112 32 ) ( -320 -112 33 ) ( -319 -112 32 ) e1u1/floor1_1 [ 1.0000000000000002 0 0 0 ] [ 0 0 1.0000000000000002 16 ] 0 1 1
+( -320 -112 32 ) ( -319 -112 32 ) ( -320 -111 32 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
+( -256 -64 40 ) ( -256 -63 40 ) ( -255 -64 40 ) e1u1/floor1_1 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
+( -256 -64 40 ) ( -255 -64 40 ) ( -256 -64 41 ) e1u1/floor1_1 [ 1.0000000000000002 0 0 0 ] [ 0 0 -1.0000000000000002 -32 ] 0 1 1
+( -256 -64 40 ) ( -256 -64 41 ) ( -256 -63 40 ) e1u1/floor1_1 [ 0 0 1.0000000000000002 32 ] [ 0 -1.0000000000000002 0 0 ] 0 1 1
+}
 }
 // entity 1
 {
 "classname" "info_player_start"
-"origin" "152 -256 96"
+"origin" "-136 272 96"
-"angle" "90"
+"angle" "270"
 }
 // entity 2
 {
@@ -85,3 +121,47 @@
 "delay" "3"
 "_anglesense" "0"
 }
+// entity 3
+{
+"classname" "light"
+"origin" "-296 -96 248"
+"light" "150"
+"delay" "3"
+"_anglesense" "0"
+}
+// entity 4
+{
+"classname" "func_group"
+"_light_alpha" "0"
+// brush 0
+{
+( -384 -176 176 ) ( -384 -175 176 ) ( -384 -176 177 ) e1u1/skip [ 0 -1 0 0 ] [ 0 0 -1 16 ] 0 1 1 32 128 0
+( -424 -176 176 ) ( -424 -176 177 ) ( -423 -176 176 ) e1u1/skip [ -1.0000000000000002 0 0 16 ] [ 0 0 -1.0000000000000002 16 ] 0 1 1 32 128 0
+( -424 -176 208 ) ( -423 -176 208 ) ( -424 -175 208 ) e1u1/skip [ 0 -1.0000000000000002 0 0 ] [ -1.0000000000000002 0 0 0 ] 0 1 1 32 128 0
+( -112 48 224 ) ( -112 49 224 ) ( -111 48 224 ) e1u1/test [ 1 0 0 32 ] [ 0 -1 0 32 ] 0 2 2 32 32 0
+( -112 0 184 ) ( -111 0 184 ) ( -112 0 185 ) e1u1/skip [ 1.0000000000000002 0 0 0 ] [ 0 0 -1.0000000000000002 16 ] 0 1 1 32 128 0
+( -192 48 184 ) ( -192 48 185 ) ( -192 49 184 ) e1u1/skip [ 0 -1 0 0 ] [ 0 0 -1 16 ] 0 1 1 32 128 0
+}
+}
+// entity 5
+{
+"classname" "light"
+"origin" "-616 -96 248"
+"light" "150"
+"delay" "3"
+"_anglesense" "0"
+}
+// entity 6
+{
+"classname" "func_group"
+"_light_alpha" "1"
+// brush 0
+{
+( -704 -176 176 ) ( -704 -175 176 ) ( -704 -176 177 ) e1u1/skip [ 0 -1 0 0 ] [ 0 0 -1 16 ] 0 1 1 32 128 0
+( -744 -176 176 ) ( -744 -176 177 ) ( -743 -176 176 ) e1u1/skip [ -1.0000000000000002 0 0 -16 ] [ 0 0 -1.0000000000000002 16 ] 0 1 1 32 128 0
+( -744 -176 208 ) ( -743 -176 208 ) ( -744 -175 208 ) e1u1/skip [ 0 -1.0000000000000002 0 0 ] [ -1.0000000000000002 0 0 0 ] 0 1 1 32 128 0
+( -432 48 224 ) ( -432 49 224 ) ( -431 48 224 ) e1u1/test [ 1 0 0 0 ] [ 0 -1 0 32 ] 0 2 2 32 32 0
+( -432 0 184 ) ( -431 0 184 ) ( -432 0 185 ) e1u1/skip [ 1.0000000000000002 0 0 0 ] [ 0 0 -1.0000000000000002 16 ] 0 1 1 32 128 0
+( -512 48 184 ) ( -512 48 185 ) ( -512 49 184 ) e1u1/skip [ 0 -1 0 0 ] [ 0 0 -1 16 ] 0 1 1 32 128 0
+}
+}

tests/test_ltface.cc

@@ -243,6 +243,7 @@ TEST_CASE("q2_light_translucency") {
 
     auto [bsp, bspx] = LoadTestmap("q2_light_translucency.map", {});
 
+    {
         auto *face_under_water = BSP_FindFaceAtPoint(&bsp, &bsp.dmodels[0], {152, -96, 32});
         REQUIRE(face_under_water);
 
@@ -252,6 +253,29 @@ TEST_CASE("q2_light_translucency") {
         });
     }
 
+    {
+        INFO("under _light_alpha 0 is not tinted");
+
+        auto *under_alpha_0_glass = BSP_FindFaceAtPoint(&bsp, &bsp.dmodels[0], {-296, -96, 40});
+        REQUIRE(under_alpha_0_glass);
+
+        CheckFaceLuxels(bsp, *under_alpha_0_glass, [](qvec3b sample) {
+            CHECK(sample == qvec3b(150));
+        });
+    }
+
+    {
+        INFO("under _light_alpha 1 is fully tinted");
+
+        auto *under_alpha_1_glass = BSP_FindFaceAtPoint(&bsp, &bsp.dmodels[0], {-616, -96, 40});
+        REQUIRE(under_alpha_1_glass);
+
+        CheckFaceLuxels(bsp, *under_alpha_1_glass, [](qvec3b sample) {
+            CHECK(sample == qvec3b(0, 150, 0));
+        });
+    }
+}
+
 TEST_CASE("-visapprox vis with opaque liquids") {
     INFO("opaque liquids block vis, but don't cast shadows by default.");
     INFO("make sure '-visapprox vis' doesn't wrongly cull rays that should illuminate the level.");