Restrict each drawable light to its lumens level (overtop lighting)

Environmental lighting continues to allow overlap between lumens levels as these are meant to be more natural and less
mechanical regarding their rendering.

src/main/java/net/rptools/maptool/client/ui/zone/Illumination.java

@@ -173,6 +173,24 @@ public Optional<LumensLevel> getObscuredLumensLevel(int lumensStrength) {
     return Collections.unmodifiableList(this.obscuredLumensLevels);
   }
 
+  /**
+   * Look up a disjoint obscured lumens level based on the lumens strength.
+   *
+   * <p>This is useful for rendering individual lights, so that the light can be constrained to the
+   * area that is actually illuminated by the light and not by any stronger light.
+   *
+   * <p>See {@link #getDisjointObscuredLumensLevels()} for more information.
+   *
+   * @param lumensStrength The strength of lumens to find.
+   * @return The {#link LumensLevel} of strength {@code lumensStrength}. If no level exists for it,
+   *     an empty optional is returned.
+   */
+  public Optional<LumensLevel> getDisjointObscuredLumensLevel(int lumensStrength) {
+    return getDisjointObscuredLumensLevels().stream()
+        .filter(level -> level.lumensStrength() == lumensStrength)
+        .findFirst();
+  }
+
   /**
    * Get the disjoint obscured lumens levels.
    *

src/main/java/net/rptools/maptool/client/ui/zone/ZoneView.java

@@ -39,6 +39,7 @@
 import net.rptools.maptool.model.zones.TokensChanged;
 import net.rptools.maptool.model.zones.TokensRemoved;
 import net.rptools.maptool.model.zones.TopologyChanged;
+import net.rptools.maptool.model.zones.ZoneLightingChanged;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -724,6 +725,8 @@ public Collection<DrawableLight> getDrawableLights(PlayerView view) {
         drawableLights.computeIfAbsent(
             view,
             view2 -> {
+              final var lightingStyle = zone.getLightingStyle();
+
               final var illuminationKey = illuminationKeyFromView(view2);
               final var illuminationModel = getIlluminationModel(illuminationKey);
 
@@ -755,9 +758,16 @@ public Collection<DrawableLight> getDrawableLights(PlayerView view) {
                         // Make sure each drawable light is restricted to the area it covers,
                         // accounting for darkness effects.
                         final var obscuredArea = new Area(laud.litArea().area());
+
+                        final var lumensStrength = Math.abs(laud.litArea().lumens());
                         final var lumensLevel =
-                            illumination.getObscuredLumensLevel(Math.abs(laud.litArea().lumens()));
-                        // Should always be present based on construction, but just in case.
+                            switch (lightingStyle) {
+                              case ENVIRONMENTAL -> illumination.getObscuredLumensLevel(
+                                  lumensStrength);
+                              case OVERTOP -> illumination.getDisjointObscuredLumensLevel(
+                                  lumensStrength);
+                            };
+                        // Should always be present based on construction, but just in case...
                         if (lumensLevel.isEmpty()) {
                           return null;
                         }
@@ -794,14 +804,18 @@ public void flush() {
     exposedAreaMap.clear();
     visibleAreaMap.clear();
 
-    drawableLights.clear();
-    drawableAuras.clear();
+    flushLights();
   }
 
   public void flushFog() {
     exposedAreaMap.clear();
   }
 
+  private void flushLights() {
+    drawableLights.clear();
+    drawableAuras.clear();
+  }
+
   /**
    * Flush the ZoneView cache of the token. Remove token from {@link #tokenVisionCachePerView}, and
    * {@link #illuminationModels}. Can clear {@link #tokenVisionCachePerView}, {@link
@@ -860,6 +874,15 @@ private void onTopologyChanged(TopologyChanged event) {
     topologyTrees.clear();
   }
 
+  @Subscribe
+  private void onZoneLightingChanged(ZoneLightingChanged event) {
+    if (event.zone() != this.zone) {
+      return;
+    }
+
+    flushLights();
+  }
+
   private boolean flushExistingTokens(List<Token> tokens) {
     boolean tokenChangedTopology = false;
     for (Token token : tokens) {
@@ -896,8 +919,7 @@ private void onTokensRemoved(TokensRemoved event) {
     }
 
     if (anyLightingChanges) {
-      drawableLights.clear();
-      drawableAuras.clear();
+      flushLights();
     }
 
     if (event.tokens().stream().anyMatch(Token::hasAnyTopology)) {
@@ -963,8 +985,7 @@ private void updateLightSourcesFromTokens(Iterable<Token> tokens) {
     }
 
     if (anyLightingChanges) {
-      drawableLights.clear();
-      drawableAuras.clear();
+      flushLights();
     }
   }
 }

src/main/java/net/rptools/maptool/model/Zone.java

@@ -61,6 +61,7 @@
 import net.rptools.maptool.model.zones.TokensChanged;
 import net.rptools.maptool.model.zones.TokensRemoved;
 import net.rptools.maptool.model.zones.TopologyChanged;
+import net.rptools.maptool.model.zones.ZoneLightingChanged;
 import net.rptools.maptool.server.Mapper;
 import net.rptools.maptool.server.proto.DrawnElementListDto;
 import net.rptools.maptool.server.proto.TopologyTypeDto;
@@ -515,6 +516,7 @@ public LightingStyle getLightingStyle() {
 
   public void setLightingStyle(LightingStyle lightingStyle) {
     this.lightingStyle = lightingStyle;
+    new MapToolEventBus().getMainEventBus().post(new ZoneLightingChanged(this));
   }
 
   public TokenSelection getTokenSelection() {

src/main/java/net/rptools/maptool/model/zones/ZoneLightingChanged.java

@@ -0,0 +1,19 @@
+/*
+ * This software Copyright by the RPTools.net development team, and
+ * licensed under the Affero GPL Version 3 or, at your option, any later
+ * version.
+ *
+ * MapTool Source Code is distributed in the hope that it will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public
+ * License * along with this source Code.  If not, please visit
+ * <http://www.gnu.org/licenses/> and specifically the Affero license
+ * text at <http://www.gnu.org/licenses/agpl.html>.
+ */
+package net.rptools.maptool.model.zones;
+
+import net.rptools.maptool.model.Zone;
+
+public record ZoneLightingChanged(Zone zone) {}