light: add _switchableshadow_target

Switchable shadows setup which works in id1

Fixes #432

common/bsputils.cc

@@ -1099,10 +1099,10 @@ static int StyleOffset(int style, const mface_t *face, const faceextents_t &face
 }
 
 /**
- * Samples the lightmap at an integer coordinate in style 0
+ * Samples the lightmap at an integer coordinate in the given style
  */
 qvec3b LM_Sample(const mbsp_t *bsp, const mface_t *face, const lit_variant_t *lit, const faceextents_t &faceextents,
-    int byte_offset_of_face, qvec2i coord)
+    int byte_offset_of_face, qvec2i coord, int style)
 {
     if (byte_offset_of_face == -1) {
         return {0, 0, 0};
@@ -1113,7 +1113,7 @@ qvec3b LM_Sample(const mbsp_t *bsp, const mface_t *face, const lit_variant_t *li
     Q_assert(coord[0] < faceextents.width());
     Q_assert(coord[1] < faceextents.height());
 
-    int style_offset = StyleOffset(0, face, faceextents);
+    int style_offset = StyleOffset(style, face, faceextents);
     if (style_offset == -1) {
         return {0, 0, 0};
     }

docs/light.rst

@@ -665,6 +665,11 @@ If used on func_detail* or func_group, a full qbsp pass need to be run.
    through the switchable shadow casters, regardless of whether the shadow
    is off or on.
 
+   .. seealso::
+
+      The light entity key :light-key:`_switchableshadow_target` allows using switchable
+      shadows in ID1 Quake, without custom QC, although the setup is more awkward.
+
 .. bmodel-key:: "_dirt" "n"
 
    For brush models, -1 prevents dirtmapping on the brush model. Useful
@@ -918,6 +923,21 @@ Point Lights
    Set to 1 to make the light compiler ignore this entity (prevents it
    from casting any light). e.g. could be useful with rtlights.
 
+.. light-key:: "_switchableshadow_target" "name"
+
+   Calculate lighting with and without bmodels with a "targetname" equal to "name",
+   and stores the resulting switchable shadow data in a light style which is stored in this light
+   entity's "style" key.
+
+   You should give this light a :light-key:`targetname` and typically set "spawnflags" "1" (start off).
+
+   Implies :light-key:`_nostaticlight` (this entity itself does not cast any light).
+
+   .. hint::
+
+      If your mod supports it, you should prefer to use bmodel key :bmodel-key:`_switchableshadow`
+      to enable switchable shadows.
+
 Spotlights
 ----------
 

include/common/bsputils.hh

@@ -176,7 +176,7 @@ public:
 };
 
 qvec3b LM_Sample(const mbsp_t *bsp, const mface_t *face, const lit_variant_t *lit, const faceextents_t &faceextents,
-    int byte_offset_of_face, qvec2i coord);
+    int byte_offset_of_face, qvec2i coord, int style = 0);
 
 qvec3f LM_Sample_HDR(const mbsp_t *bsp,
                      const mface_t *face,

include/light/entities.hh

@@ -113,6 +113,7 @@ public:
     settings::setting_int32 light_channel_mask;
     settings::setting_int32 shadow_channel_mask;
     settings::setting_bool nonudge;
+    settings::setting_string switchableshadow_target;
 
     light_t();
 
@@ -143,6 +144,10 @@ std::vector<std::unique_ptr<light_t>> &GetLights();
 const std::vector<entdict_t> &GetEntdicts();
 std::vector<sun_t> &GetSuns();
 std::vector<entdict_t> &GetRadLights();
+/**
+ * Returns the light entity that has "_switchableshadow_target" set to the given value, or nullptr.
+ */
+light_t *LightWithSwitchableShadowTargetValue(const std::string &target);
 
 const std::vector<std::unique_ptr<light_t>> &GetSurfaceLightTemplates();
 

light/entities.cc

@@ -42,6 +42,7 @@ static std::vector<std::pair<std::string, int>> lightstyleForTargetname;
 static std::vector<std::unique_ptr<light_t>> surfacelight_templates;
 static std::ofstream surflights_dump_file;
 static fs::path surflights_dump_filename;
+static std::map<std::string, light_t*> lights_by_switchableshadow_target;
 
 /**
  * Resets global data in this file
@@ -58,6 +59,7 @@ void ResetLightEntities()
     surfacelight_templates.clear();
     surflights_dump_file = {};
     surflights_dump_filename.clear();
+    lights_by_switchableshadow_target.clear();
 }
 
 std::vector<std::unique_ptr<light_t>> &GetLights()
@@ -80,6 +82,16 @@ std::vector<entdict_t> &GetRadLights()
     return radlights;
 }
 
+light_t *LightWithSwitchableShadowTargetValue(const std::string &target)
+{
+    auto it = lights_by_switchableshadow_target.find(target);
+
+    if (it == lights_by_switchableshadow_target.end())
+        return nullptr;
+
+    return it->second;
+}
+
 /* surface lights */
 static void MakeSurfaceLights(const mbsp_t *bsp);
 
@@ -121,7 +133,8 @@ light_t::light_t()
       surflight_atten{this, "surflight_atten", 1.f},
       light_channel_mask{this, "light_channel_mask", CHANNEL_MASK_DEFAULT},
       shadow_channel_mask{this, "shadow_channel_mask", CHANNEL_MASK_DEFAULT},
-      nonudge{this, "nonudge", false}
+      nonudge{this, "nonudge", false},
+      switchableshadow_target{this, "switchableshadow_target", ""}
 {
 }
 
@@ -1062,6 +1075,14 @@ void LoadEntities(const settings::worldspawn_keys &cfg, const mbsp_t *bsp)
                         entity->projfov.value(), entity->projectionmatrix);
             }
 
+            // vanilla-compatible switchable shadows
+            const std::string &switchableshadow_target = entity->switchableshadow_target.value();
+            if (!switchableshadow_target.empty()) {
+                entity->nostaticlight.set_value(true, settings::source::DEFAULT);
+
+                lights_by_switchableshadow_target[switchableshadow_target] = entity.get();
+            }
+
             CheckEntityFields(bsp, cfg, entity.get());
         }
     }

light/light.cc

@@ -725,6 +725,13 @@ static void FindModelInfo(const mbsp_t *bsp)
         // apply settings
         info->set_settings(*entdict, settings::source::MAP);
 
+        // vanilla-compatible switchable shadows
+        if (auto *light = LightWithSwitchableShadowTargetValue(entdict->get("targetname"))) {
+            // take the "style" key from this light entity and enable switchable shadows on ourself
+            info->switchableshadow.set_value(true, settings::source::DEFAULT);
+            info->switchshadstyle.set_value(light->style.value(), settings::source::DEFAULT);
+        }
+
         /* Check if this model will cast shadows (shadow => shadowself) */
         if (info->switchableshadow.boolValue()) {
             Q_assert(info->switchshadstyle.value() != 0);

testmaps/q1_light_switchableshadow_target.map

@@ -0,0 +1,184 @@
+// Game: Quake
+// Format: Standard
+// entity 0
+{
+"classname" "worldspawn"
+"_tb_textures" "textures/e1u1"
+"wad" "deprecated/free_wad.wad"
+// brush 0
+{
+( 480 1088 928 ) ( 480 1089 928 ) ( 480 1088 929 ) bolt14 0 32 0 1 1
+( 704 1088 928 ) ( 704 1088 929 ) ( 705 1088 928 ) bolt14 0 32 0 1 1
+( 704 1088 928 ) ( 705 1088 928 ) ( 704 1089 928 ) bolt14 0 0 0 1 1
+( 944 1472 944 ) ( 944 1473 944 ) ( 945 1472 944 ) bolt14 0 0 0 1 1
+( 944 1488 944 ) ( 945 1488 944 ) ( 944 1488 945 ) bolt14 0 32 0 1 1
+( 1056 1472 944 ) ( 1056 1472 945 ) ( 1056 1473 944 ) bolt14 0 32 0 1 1
+}
+// brush 1
+{
+( 480 1088 1248 ) ( 480 1089 1248 ) ( 480 1088 1249 ) bolt14 0 96 0 1 1
+( 704 1072 1248 ) ( 704 1072 1249 ) ( 705 1072 1248 ) bolt14 0 96 0 1 1
+( 704 1088 1248 ) ( 705 1088 1248 ) ( 704 1089 1248 ) bolt14 0 0 0 1 1
+( 944 1472 1264 ) ( 944 1473 1264 ) ( 945 1472 1264 ) bolt14 0 0 0 1 1
+( 944 1488 1264 ) ( 945 1488 1264 ) ( 944 1488 1265 ) bolt14 0 96 0 1 1
+( 1056 1472 1264 ) ( 1056 1472 1265 ) ( 1056 1473 1264 ) bolt14 0 96 0 1 1
+}
+// brush 2
+{
+( 480 1072 928 ) ( 480 1073 928 ) ( 480 1072 929 ) bolt14 16 32 0 1 1
+( 704 1072 928 ) ( 704 1072 929 ) ( 705 1072 928 ) bolt14 0 32 0 1 1
+( 704 1072 928 ) ( 705 1072 928 ) ( 704 1073 928 ) bolt14 0 -16 0 1 1
+( 944 1456 1248 ) ( 944 1457 1248 ) ( 945 1456 1248 ) bolt14 0 -16 0 1 1
+( 944 1088 944 ) ( 945 1088 944 ) ( 944 1088 945 ) bolt14 0 32 0 1 1
+( 1056 1456 944 ) ( 1056 1456 945 ) ( 1056 1457 944 ) bolt14 16 32 0 1 1
+}
+// brush 3
+{
+( 480 1392 928 ) ( 480 1393 928 ) ( 480 1392 929 ) bolt14 -48 32 0 1 1
+( 832 1488 928 ) ( 832 1488 929 ) ( 833 1488 928 ) bolt14 -128 32 0 1 1
+( 832 1392 928 ) ( 833 1392 928 ) ( 832 1393 928 ) bolt14 -128 48 0 1 1
+( 1072 1776 1248 ) ( 1072 1777 1248 ) ( 1073 1776 1248 ) bolt14 -128 48 0 1 1
+( 1072 1504 944 ) ( 1073 1504 944 ) ( 1072 1504 945 ) bolt14 -128 32 0 1 1
+( 1056 1392 928 ) ( 1056 1392 929 ) ( 1056 1393 928 ) bolt14 -48 32 0 1 1
+}
+// brush 4
+{
+( 1056 1088 1056 ) ( 1056 1089 1056 ) ( 1056 1088 1057 ) bolt14 0 32 0 1 1
+( 736 1088 1056 ) ( 736 1088 1057 ) ( 737 1088 1056 ) bolt14 -32 32 0 1 1
+( 736 1088 928 ) ( 737 1088 928 ) ( 736 1089 928 ) bolt14 -32 0 0 1 1
+( 976 1472 1248 ) ( 976 1473 1248 ) ( 977 1472 1248 ) bolt14 -32 0 0 1 1
+( 976 1488 1072 ) ( 977 1488 1072 ) ( 976 1488 1073 ) bolt14 -32 32 0 1 1
+( 1072 1472 1072 ) ( 1072 1472 1073 ) ( 1072 1473 1072 ) bolt14 0 32 0 1 1
+}
+// brush 5
+{
+( 464 1088 1056 ) ( 464 1089 1056 ) ( 464 1088 1057 ) bolt14 0 32 0 1 1
+( 144 1072 1056 ) ( 144 1072 1057 ) ( 145 1072 1056 ) bolt14 48 32 0 1 1
+( 144 1088 928 ) ( 145 1088 928 ) ( 144 1089 928 ) bolt14 48 0 0 1 1
+( 384 1472 1248 ) ( 384 1473 1248 ) ( 385 1472 1248 ) bolt14 48 0 0 1 1
+( 384 1488 1072 ) ( 385 1488 1072 ) ( 384 1488 1073 ) bolt14 48 32 0 1 1
+( 480 1472 1072 ) ( 480 1472 1073 ) ( 480 1473 1072 ) bolt14 0 32 0 1 1
+}
+// brush 6
+{
+( 704 1088 944 ) ( 704 1089 944 ) ( 704 1088 945 ) bolt10 0 0 0 1 1
+( 704 1088 944 ) ( 704 1088 945 ) ( 705 1088 944 ) bolt10 0 0 0 1 1
+( 704 1088 944 ) ( 705 1088 944 ) ( 704 1089 944 ) bolt10 0 0 0 1 1
+( 720 1216 1008 ) ( 720 1217 1008 ) ( 721 1216 1008 ) bolt10 0 0 0 1 1
+( 720 1216 960 ) ( 721 1216 960 ) ( 720 1216 961 ) bolt10 0 0 0 1 1
+( 720 1216 960 ) ( 720 1216 961 ) ( 720 1217 960 ) bolt10 0 0 0 1 1
+}
+// brush 7
+{
+( 704 1088 944 ) ( 704 1089 944 ) ( 704 1088 945 ) bolt10 0 0 0 1 1
+( 720 1344 960 ) ( 720 1344 961 ) ( 721 1344 960 ) bolt10 0 0 0 1 1
+( 704 1088 944 ) ( 705 1088 944 ) ( 704 1089 944 ) bolt10 0 0 0 1 1
+( 720 1216 1008 ) ( 720 1217 1008 ) ( 721 1216 1008 ) bolt10 0 0 0 1 1
+( 720 1488 960 ) ( 721 1488 960 ) ( 720 1488 961 ) bolt10 0 0 0 1 1
+( 720 1216 960 ) ( 720 1216 961 ) ( 720 1217 960 ) bolt10 0 0 0 1 1
+}
+// brush 8
+{
+( 704 1088 944 ) ( 704 1089 944 ) ( 704 1088 945 ) bolt10 0 0 0 1 1
+( 704 1088 944 ) ( 704 1088 945 ) ( 705 1088 944 ) bolt10 0 0 0 1 1
+( 720 1216 1008 ) ( 721 1216 1008 ) ( 720 1217 1008 ) bolt10 0 0 0 1 1
+( 720 1216 1016 ) ( 720 1217 1016 ) ( 721 1216 1016 ) bolt10 0 0 0 1 1
+( 720 1488 960 ) ( 721 1488 960 ) ( 720 1488 961 ) bolt10 0 0 0 1 1
+( 720 1216 960 ) ( 720 1216 961 ) ( 720 1217 960 ) bolt10 0 0 0 1 1
+}
+}
+// entity 1
+{
+"classname" "info_player_start"
+"origin" "848 1280 968"
+"angle" "180"
+}
+// entity 2
+{
+"classname" "light"
+"origin" "760 1280 1048"
+"light" "1000"
+"targetname" "toggle_door1_shadow"
+"spawnflags" "1"
+"_switchableshadow_target" "door1"
+}
+// entity 3
+{
+"classname" "light"
+"origin" "568 1264 952"
+"_color" "1 0 0"
+"light" "500"
+}
+// entity 4
+{
+"classname" "func_door"
+"targetname" "door1"
+"spawnflags" "32"
+"angle" "-2"
+"speed" "1000"
+// brush 0
+{
+( 704 1320 944 ) ( 704 1321 944 ) ( 704 1320 945 ) bolt10 -8 0 0 1 1
+( 704 1320 944 ) ( 704 1320 945 ) ( 705 1320 944 ) bolt10 0 0 0 1 1
+( 704 1320 944 ) ( 705 1320 944 ) ( 704 1321 944 ) bolt10 0 8 0 1 1
+( 720 1448 1008 ) ( 720 1449 1008 ) ( 721 1448 1008 ) bolt10 0 8 0 1 1
+( 720 1336 960 ) ( 721 1336 960 ) ( 720 1336 961 ) bolt10 0 0 0 1 1
+( 720 1448 960 ) ( 720 1448 961 ) ( 720 1449 960 ) bolt10 -8 0 0 1 1
+}
+// brush 1
+{
+( 704 1224 944 ) ( 704 1225 944 ) ( 704 1224 945 ) bolt10 -8 0 0 1 1
+( 704 1224 944 ) ( 704 1224 945 ) ( 705 1224 944 ) bolt10 0 0 0 1 1
+( 704 1224 944 ) ( 705 1224 944 ) ( 704 1225 944 ) bolt10 0 8 0 1 1
+( 720 1352 1008 ) ( 720 1353 1008 ) ( 721 1352 1008 ) bolt10 0 8 0 1 1
+( 720 1240 960 ) ( 721 1240 960 ) ( 720 1240 961 ) bolt10 0 0 0 1 1
+( 720 1352 960 ) ( 720 1352 961 ) ( 720 1353 960 ) bolt10 -8 0 0 1 1
+}
+// brush 2
+{
+( 704 1256 944 ) ( 704 1257 944 ) ( 704 1256 945 ) bolt10 -8 0 0 1 1
+( 704 1256 944 ) ( 704 1256 945 ) ( 705 1256 944 ) bolt10 0 0 0 1 1
+( 704 1256 944 ) ( 705 1256 944 ) ( 704 1257 944 ) bolt10 0 8 0 1 1
+( 720 1384 1008 ) ( 720 1385 1008 ) ( 721 1384 1008 ) bolt10 0 8 0 1 1
+( 720 1272 960 ) ( 721 1272 960 ) ( 720 1272 961 ) bolt10 0 0 0 1 1
+( 720 1384 960 ) ( 720 1384 961 ) ( 720 1385 960 ) bolt10 -8 0 0 1 1
+}
+// brush 3
+{
+( 704 1288 944 ) ( 704 1289 944 ) ( 704 1288 945 ) bolt10 -8 0 0 1 1
+( 704 1288 944 ) ( 704 1288 945 ) ( 705 1288 944 ) bolt10 0 0 0 1 1
+( 704 1288 944 ) ( 705 1288 944 ) ( 704 1289 944 ) bolt10 0 8 0 1 1
+( 720 1416 1008 ) ( 720 1417 1008 ) ( 721 1416 1008 ) bolt10 0 8 0 1 1
+( 720 1304 960 ) ( 721 1304 960 ) ( 720 1304 961 ) bolt10 0 0 0 1 1
+( 720 1416 960 ) ( 720 1416 961 ) ( 720 1417 960 ) bolt10 -8 0 0 1 1
+}
+}
+// entity 5
+{
+"classname" "func_button"
+"target" "switch1"
+"angle" "-2"
+// brush 0
+{
+( 752 1288 952 ) ( 752 1289 952 ) ( 752 1288 953 ) swire2 -56 0 0 1 1
+( 792 1272 944 ) ( 791 1272 944 ) ( 792 1272 945 ) swire2 48 0 180 1 -1
+( 792 1248 944 ) ( 792 1249 944 ) ( 791 1248 944 ) swire2 -56 -48 90 1 1
+( 744 1288 952 ) ( 743 1288 952 ) ( 744 1289 952 ) +0switch -8 -16 90 1 1
+( 744 1288 952 ) ( 744 1288 953 ) ( 743 1288 952 ) swire2 48 0 180 1 -1
+( 784 1248 944 ) ( 784 1248 945 ) ( 784 1249 944 ) swire2 -56 0 0 1 1
+}
+}
+// entity 6
+{
+"classname" "trigger_relay"
+"origin" "760 1256 1000"
+"targetname" "switch1"
+"target" "door1"
+}
+// entity 7
+{
+"classname" "trigger_relay"
+"origin" "760 1320 1000"
+"targetname" "switch1"
+"target" "toggle_door1_shadow"
+}

tests/test_ltface.cc

@@ -319,7 +319,7 @@ static void CheckFaceLuxelsNonBlack(const mbsp_t &bsp, const mface_t &face)
 
 static void CheckFaceLuxelAtPoint(const mbsp_t *bsp, const dmodelh2_t *model, const qvec3b &expected_color,
     const qvec3d &point, const qvec3d &normal = {0, 0, 0}, const lit_variant_t *lit = nullptr,
-    const bspxentries_t *bspx = nullptr)
+    const bspxentries_t *bspx = nullptr, int style = 0)
 {
     auto *face = BSP_FindFaceAtPoint(bsp, model, point, normal);
     ASSERT_TRUE(face);
@@ -340,7 +340,7 @@ static void CheckFaceLuxelAtPoint(const mbsp_t *bsp, const dmodelh2_t *model, co
     const auto coord = extents.worldToLMCoord(point);
     const auto int_coord = qvec2i(round(coord[0]), round(coord[1]));
 
-    const qvec3b sample = LM_Sample(bsp, face, lit, extents, offset, int_coord);
+    const qvec3b sample = LM_Sample(bsp, face, lit, extents, offset, int_coord, style);
     SCOPED_TRACE(fmt::format("world point: {}", point));
     SCOPED_TRACE(fmt::format("lm coord: {}", coord));
     SCOPED_TRACE(fmt::format("lm int_coord: {}", int_coord));
@@ -1145,4 +1145,35 @@ TEST(ltfaceQ1, hdr)
         // check internal lightmap - greyscale, since Q1
         CheckFaceLuxelAtPoint(&bsp, &bsp.dmodels[0], {0, 0, 0}, testpoint, testnormal);
     }
+}
+
+TEST(ltfaceQ1, switchableshadowTarget)
+{
+    SCOPED_TRACE("Vanilla-compatible switchable shadows");
+
+    auto [bsp, bspx, lit] = QbspVisLight_Q1("q1_light_switchableshadow_target.map", {});
+
+    // find the light controlling the switchable shadow
+    auto entdicts = EntData_Parse(bsp);
+
+    auto it = std::find_if(entdicts.begin(), entdicts.end(), [](const entdict_t& dict) -> bool {
+        return dict.get("_switchableshadow_target") == "door1";
+    });
+    ASSERT_NE(it, entdicts.end());
+
+    ASSERT_TRUE(it->has("style"));
+    int switchable_style = it->get_int("style");
+
+    ASSERT_EQ(32, switchable_style);
+
+    const qvec3f not_in_shadow {792, 1240, 944};
+    const qvec3f in_shadow {792, 1264, 944};
+
+    // not in shadow - should be lit up red in style 0, and black in style 32
+    CheckFaceLuxelAtPoint(&bsp, &bsp.dmodels[0], {68, 0, 0}, not_in_shadow, {0, 0, 1}, &lit, &bspx, 0);
+    CheckFaceLuxelAtPoint(&bsp, &bsp.dmodels[0], {0, 0, 0}, not_in_shadow, {0, 0, 1}, &lit, &bspx, 32);
+
+    // in (switchable) shadow - should be black in style 0, and red in style 32
+    CheckFaceLuxelAtPoint(&bsp, &bsp.dmodels[0], {0, 0, 0}, in_shadow, {0, 0, 1}, &lit, &bspx, 0);
+    CheckFaceLuxelAtPoint(&bsp, &bsp.dmodels[0], {68, 0, 0}, in_shadow, {0, 0, 1}, &lit, &bspx, 32);
 }