Discounted occupied flower columns

- Converted patch decorators also lose the share of surface columns that earlier surface patches in the declaring biomes already occupy, estimated from those patches' expected coverage in the catalog
- Canopy and surface occupancy are combined into one vegetation occlusion estimate per decorated feature

core/src/main/java/art/arcane/iris/pack/ingest/ModFeatureIngester.java

@@ -45,7 +45,7 @@ final class ModFeatureIngester {
     private final IngestPackModel model;
     private final WorldgenCatalogIndex index;
     private final TreeFeatures trees;
-    private final CanopyEstimate canopy;
+    private final VegetationOcclusion occlusion;
     private final Map<String, FeaturePlan> plans = new TreeMap<>();
     private final Set<String> nativeKeys = new TreeSet<>();
     private final Set<String> vanillaScopedKeys = new TreeSet<>();
@@ -54,7 +54,7 @@ final class ModFeatureIngester {
         this.model = model;
         this.index = index;
         this.trees = new TreeFeatures(index);
-        this.canopy = new CanopyEstimate(index);
+        this.occlusion = new VegetationOcclusion(index);
         Map<String, Set<String>> declaring = new TreeMap<>();
         Map<String, Set<Integer>> steps = new TreeMap<>();
         for (CatalogBiome biome : index.catalog().biomes()) {
@@ -210,7 +210,7 @@ final class ModFeatureIngester {
             }
             if (PatchDecoratorConverter.handles(placed)) {
                 return new FeaturePlan(key, declaring, steps, null,
-                        PatchDecoratorConverter.convert(placed, index, canopy.occlusion(key, declaring)), "");
+                        PatchDecoratorConverter.convert(placed, index, occlusion.occlusion(key, declaring)), "");
             }
         } catch (IngestConversionException e) {
             return FeaturePlan.passthrough(key, declaring, steps, "generated natively: " + e.getMessage());

core/src/main/java/art/arcane/iris/pack/ingest/PatchDecoratorConverter.java

@@ -45,30 +45,23 @@ final class PatchDecoratorConverter {
         return type.equals(SIMPLE_BLOCK) || LEGACY_PATCH_TYPES.contains(type);
     }
 
-    static JsonObject convert(CatalogPlacedFeature feature, WorldgenCatalogIndex index, double canopy) throws IngestConversionException {
+    static JsonObject convert(CatalogPlacedFeature feature, WorldgenCatalogIndex index,
+                              VegetationOcclusion.Occlusion occlusion) throws IngestConversionException {
         String type = VanillaJson.namespaced(feature.featureType());
         JsonObject config = VanillaJson.featureConfig(feature.config());
         VanillaPlacementChain outer = VanillaPlacementChain.surfaceChain(VanillaJson.placement(feature.placement()));
         Set<String> whitelist = new LinkedHashSet<>(outer.whitelist());
-        double expected;
         JsonElement provider;
         if (LEGACY_PATCH_TYPES.contains(type)) {
-            int tries = VanillaJson.integer(config, "tries", LEGACY_DEFAULT_TRIES, "patch");
-            int verticalSpread = Math.abs(VanillaJson.integer(config, "y_spread", LEGACY_DEFAULT_Y_SPREAD, "patch"));
-            double surfaceHitChance = outer.surfaceHitChance() / (verticalSpread + 1D);
             NestedBlock nested = nestedBlock(config.get("feature"), index);
             whitelist.addAll(nested.whitelist());
             provider = nested.provider();
-            expected = outer.expectedPlacements() * tries * surfaceHitChance;
         } else {
             provider = config.get("to_place");
-            expected = outer.expectedPlacements() * outer.surfaceHitChance();
-        }
-        if (expected <= 0D) {
-            throw new IngestConversionException("patch placement never places");
         }
+        double expected = expectedPlacements(feature, index) * (1D - clamp(occlusion.occupancy()));
         if (outer.leafBlocked()) {
-            expected *= 1D - Math.max(0D, Math.min(1D, canopy));
+            expected *= 1D - clamp(occlusion.canopy());
         }
         List<JsonObject> palette = VanillaBlockStates.palette(provider);
         JsonObject decorator = new JsonObject();
@@ -90,6 +83,27 @@ final class PatchDecoratorConverter {
         return decorator;
     }
 
+    static double expectedPlacements(CatalogPlacedFeature feature, WorldgenCatalogIndex index) throws IngestConversionException {
+        JsonObject config = VanillaJson.featureConfig(feature.config());
+        VanillaPlacementChain outer = VanillaPlacementChain.surfaceChain(VanillaJson.placement(feature.placement()));
+        double expected;
+        if (LEGACY_PATCH_TYPES.contains(VanillaJson.namespaced(feature.featureType()))) {
+            int tries = VanillaJson.integer(config, "tries", LEGACY_DEFAULT_TRIES, "patch");
+            int verticalSpread = Math.abs(VanillaJson.integer(config, "y_spread", LEGACY_DEFAULT_Y_SPREAD, "patch"));
+            expected = outer.expectedPlacements() * tries * outer.surfaceHitChance() / (verticalSpread + 1D);
+        } else {
+            expected = outer.expectedPlacements() * outer.surfaceHitChance();
+        }
+        if (expected <= 0D) {
+            throw new IngestConversionException("patch placement never places");
+        }
+        return expected;
+    }
+
+    private static double clamp(double share) {
+        return Math.max(0D, Math.min(1D, share));
+    }
+
     static double columnCoverage(double expectedPlacements) {
         return 1D - Math.exp(-expectedPlacements / COLUMNS_PER_CHUNK);
     }

core/src/main/java/art/arcane/iris/pack/ingest/VegetationOcclusion.java

@@ -27,7 +27,7 @@ import java.util.List;
 import java.util.Optional;
 import java.util.Set;
 
-final class CanopyEstimate {
+final class VegetationOcclusion {
     static final double CROWN_COLUMNS = 20D;
     private static final double UNKNOWN_TREE_COUNT = 1D;
     private static final double COLUMNS_PER_CHUNK = 256D;
@@ -36,39 +36,55 @@ final class CanopyEstimate {
     private final WorldgenCatalogIndex index;
     private final TreeFeatures trees;
 
-    CanopyEstimate(WorldgenCatalogIndex index) {
+    VegetationOcclusion(WorldgenCatalogIndex index) {
         this.index = index;
         this.trees = new TreeFeatures(index);
     }
 
-    double occlusion(String featureKey, Set<String> declaringBiomes) {
+    Occlusion occlusion(String featureKey, Set<String> declaringBiomes) {
         if (declaringBiomes.isEmpty()) {
-            return 0D;
+            return Occlusion.NONE;
         }
-        double total = 0D;
+        double canopy = 0D;
+        double occupancy = 0D;
         for (String biomeKey : declaringBiomes) {
             Optional<CatalogBiome> biome = index.biome(biomeKey);
-            total += biome.map((CatalogBiome value) -> canopyBefore(value, featureKey)).orElse(0D);
+            if (biome.isEmpty() || biome.get().featureSteps().size() <= VEGETAL_STEP) {
+                continue;
+            }
+            Occlusion before = before(biome.get().featureSteps().get(VEGETAL_STEP), featureKey);
+            canopy += before.canopy();
+            occupancy += before.occupancy();
         }
-        return total / declaringBiomes.size();
+        return new Occlusion(canopy / declaringBiomes.size(), occupancy / declaringBiomes.size());
     }
 
-    private double canopyBefore(CatalogBiome biome, String featureKey) {
-        if (biome.featureSteps().size() <= VEGETAL_STEP) {
-            return 0D;
-        }
-        List<String> vegetal = biome.featureSteps().get(VEGETAL_STEP);
+    private Occlusion before(List<String> vegetal, String featureKey) {
         double treesPerChunk = 0D;
+        double open = 1D;
         for (String candidate : vegetal) {
             if (candidate.equals(featureKey)) {
                 break;
             }
             Optional<CatalogPlacedFeature> feature = index.placedFeature(candidate);
-            if (feature.isPresent() && trees.isTree(feature.get())) {
+            if (feature.isEmpty()) {
+                continue;
+            }
+            if (trees.isTree(feature.get())) {
                 treesPerChunk += treesPerChunk(feature.get());
+            } else if (PatchDecoratorConverter.handles(feature.get())) {
+                open *= 1D - surfaceCoverage(feature.get());
             }
         }
-        return 1D - Math.exp(-treesPerChunk * CROWN_COLUMNS / COLUMNS_PER_CHUNK);
+        return new Occlusion(1D - Math.exp(-treesPerChunk * CROWN_COLUMNS / COLUMNS_PER_CHUNK), 1D - open);
+    }
+
+    private double surfaceCoverage(CatalogPlacedFeature patch) {
+        try {
+            return PatchDecoratorConverter.columnCoverage(PatchDecoratorConverter.expectedPlacements(patch, index));
+        } catch (IngestConversionException unknownDensity) {
+            return 0D;
+        }
     }
 
     private static double treesPerChunk(CatalogPlacedFeature tree) {
@@ -78,4 +94,8 @@ final class CanopyEstimate {
             return UNKNOWN_TREE_COUNT;
         }
     }
+
+    record Occlusion(double canopy, double occupancy) {
+        static final Occlusion NONE = new Occlusion(0D, 0D);
+    }
 }

core/src/test/java/art/arcane/iris/pack/ingest/FeatureConverterFormatTest.java

@@ -115,7 +115,7 @@ public class FeatureConverterFormatTest {
                         + "{\"type\": \"minecraft:heightmap\", \"heightmap\": \"WORLD_SURFACE_WG\"}, {\"type\": \"minecraft:biome\"},"
                         + "{\"type\": \"minecraft:count\", \"count\": 96}," + PATCH_TAIL + "]");
 
-        JsonObject decorator = PatchDecoratorConverter.convert(lavender, index(), 0D);
+        JsonObject decorator = PatchDecoratorConverter.convert(lavender, index(), VegetationOcclusion.Occlusion.NONE);
 
         assertEquals(1.0D - Math.exp(-(15.0D * 96.0D * 0.25D) / 256.0D), decorator.get("chance").getAsDouble(), 0.000001D);
         assertTrue(decorator.get("chance").getAsDouble() < 1.0D);
@@ -133,9 +133,11 @@ public class FeatureConverterFormatTest {
                         + "{\"type\": \"minecraft:heightmap\", \"heightmap\": \"MOTION_BLOCKING_NO_LEAVES\"}, {\"type\": \"minecraft:biome\"}]");
 
         assertEquals(1.0D - Math.exp(-(4.0D * 0.5D) / 256.0D),
-                PatchDecoratorConverter.convert(lavender, index(), 0.5D).get("chance").getAsDouble(), 0.000001D);
+                PatchDecoratorConverter.convert(lavender, index(), new VegetationOcclusion.Occlusion(0.5D, 0D)).get("chance").getAsDouble(), 0.000001D);
         assertEquals(1.0D - Math.exp(-4.0D / 256.0D),
-                PatchDecoratorConverter.convert(underLeaves, index(), 0.5D).get("chance").getAsDouble(), 0.000001D);
+                PatchDecoratorConverter.convert(underLeaves, index(), new VegetationOcclusion.Occlusion(0.5D, 0D)).get("chance").getAsDouble(), 0.000001D);
+        assertEquals(1.0D - Math.exp(-(4.0D * 0.25D) / 256.0D),
+                PatchDecoratorConverter.convert(underLeaves, index(), new VegetationOcclusion.Occlusion(0D, 0.75D)).get("chance").getAsDouble(), 0.000001D);
     }
 
     @Test
@@ -152,7 +154,7 @@ public class FeatureConverterFormatTest {
                  {"type": "minecraft:biome"}]
                 """);
 
-        JsonObject decorator = PatchDecoratorConverter.convert(flowers, index(), 0D);
+        JsonObject decorator = PatchDecoratorConverter.convert(flowers, index(), VegetationOcclusion.Occlusion.NONE);
 
         assertEquals(1.0D - Math.exp(-(0.5D * 0.2D * 0.25D) / 256.0D), decorator.get("chance").getAsDouble(), 0.000001D);
         assertEquals("minecraft:grass_block", decorator.getAsJsonArray("whitelist").get(0).getAsJsonObject().get("block").getAsString());
@@ -167,8 +169,8 @@ public class FeatureConverterFormatTest {
                 "{\"type\": \"minecraft:simple_block\", \"to_place\": \"minecraft:flower_plain\"}",
                 "[{\"type\": \"minecraft:heightmap\", \"heightmap\": \"MOTION_BLOCKING\"}]");
 
-        assertThrows(IngestConversionException.class, () -> PatchDecoratorConverter.convert(seagrass, index(), 0D));
-        IngestConversionException reference = assertThrows(IngestConversionException.class, () -> PatchDecoratorConverter.convert(plains, index(), 0D));
+        assertThrows(IngestConversionException.class, () -> PatchDecoratorConverter.convert(seagrass, index(), VegetationOcclusion.Occlusion.NONE));
+        IngestConversionException reference = assertThrows(IngestConversionException.class, () -> PatchDecoratorConverter.convert(plains, index(), VegetationOcclusion.Occlusion.NONE));
         assertTrue(reference.getMessage(), reference.getMessage().contains("minecraft:flower_plain"));
     }
 

core/src/test/java/art/arcane/iris/pack/ingest/ModIngesterFeatureTest.java

@@ -123,7 +123,7 @@ public class ModIngesterFeatureTest {
         assertNotNull(mapleFlowers);
         assertNotNull(forestFlowers);
         assertEquals(2, forest.getAsJsonArray("decorators").size());
-        double mapleCanopy = 1.0D - Math.exp(-CanopyEstimate.CROWN_COLUMNS / 256.0D);
+        double mapleCanopy = 1.0D - Math.exp(-VegetationOcclusion.CROWN_COLUMNS / 256.0D);
         double openShare = 1.0D - mapleCanopy / 2.0D;
         assertEquals(1.0D - Math.exp(-(1.0D / 4.0D * 32.0D * 0.25D * openShare) / 256.0D), forestFlowers.get("chance").getAsDouble(), 0.000001D);
         JsonArray palette = forestFlowers.getAsJsonArray("palette");

core/src/test/java/art/arcane/iris/pack/ingest/VegetationOcclusionTest.java

@@ -33,26 +33,42 @@ import java.util.Set;
 
 import static org.junit.Assert.assertEquals;
 
-public class CanopyEstimateTest {
-    private static final double CANOPY = 1D - Math.exp(-10D * CanopyEstimate.CROWN_COLUMNS / 256D);
+public class VegetationOcclusionTest {
+    private static final double CANOPY = 1D - Math.exp(-10D * VegetationOcclusion.CROWN_COLUMNS / 256D);
+    private static final double GRASS_COVERAGE = 1D - Math.exp(-(24D * 32D * 0.25D) / 256D);
 
     @Test
     public void flowersPlacedAfterTreesSeeTheTreeCanopy() {
-        CanopyEstimate estimate = new CanopyEstimate(WorldgenCatalogIndex.of(catalog()));
+        VegetationOcclusion estimate = new VegetationOcclusion(WorldgenCatalogIndex.of(catalog()));
 
-        assertEquals(CANOPY, estimate.occlusion("mod:flowers_after", Set.of("mod:woods")), 0.000001D);
-        assertEquals(0D, estimate.occlusion("mod:flowers_before", Set.of("mod:woods")), 0.000001D);
-        assertEquals(CANOPY / 2D, estimate.occlusion("mod:flowers_after", Set.of("mod:woods", "mod:meadow")), 0.000001D);
+        assertEquals(CANOPY, estimate.occlusion("mod:flowers_after", Set.of("mod:woods")).canopy(), 0.000001D);
+        assertEquals(0D, estimate.occlusion("mod:flowers_before", Set.of("mod:woods")).canopy(), 0.000001D);
+        assertEquals(CANOPY / 2D, estimate.occlusion("mod:flowers_after", Set.of("mod:woods", "mod:meadow")).canopy(), 0.000001D);
+    }
+
+    @Test
+    public void surfacePatchesPlacedEarlierOccupyTheirShareOfColumns() {
+        VegetationOcclusion estimate = new VegetationOcclusion(WorldgenCatalogIndex.of(catalog()));
+
+        assertEquals(GRASS_COVERAGE, estimate.occlusion("mod:flowers_after", Set.of("mod:woods")).occupancy(), 0.000001D);
+        assertEquals(0D, estimate.occlusion("mod:flowers_before", Set.of("mod:woods")).occupancy(), 0.000001D);
+        assertEquals(GRASS_COVERAGE / 2D, estimate.occlusion("mod:flowers_after", Set.of("mod:woods", "mod:meadow")).occupancy(), 0.000001D);
     }
 
     private static WorldgenCatalog catalog() {
         List<CatalogBiome> biomes = List.of(
-                biome("mod:woods", List.of("mod:flowers_before", "mod:oak_trees", "mod:flowers_after")),
+                biome("mod:woods", List.of("mod:flowers_before", "mod:oak_trees", "mod:grass_patch", "mod:flowers_after")),
                 biome("mod:meadow", List.of("mod:flowers_after")));
         List<CatalogPlacedFeature> features = new ArrayList<>();
         features.add(new CatalogPlacedFeature("mod:oak_trees", "mod:oak_trees", "minecraft:tree", JsonParser.parseString("{}"),
                 JsonParser.parseString("[{\"type\": \"minecraft:count\", \"count\": 10}, {\"type\": \"minecraft:in_square\"},"
                         + "{\"type\": \"minecraft:surface_water_depth_filter\", \"max_water_depth\": 0}, {\"type\": \"minecraft:biome\"}]")));
+        features.add(new CatalogPlacedFeature("mod:grass_patch", "mod:grass_patch", "minecraft:simple_block",
+                JsonParser.parseString("{\"to_place\": {\"id\": \"minecraft:short_grass\"}}"),
+                JsonParser.parseString("[{\"type\": \"minecraft:count\", \"count\": 24}, {\"type\": \"minecraft:in_square\"},"
+                        + "{\"type\": \"minecraft:heightmap\", \"heightmap\": \"WORLD_SURFACE_WG\"}, {\"type\": \"minecraft:biome\"},"
+                        + "{\"type\": \"minecraft:count\", \"count\": 32},"
+                        + "{\"type\": \"minecraft:offset\", \"y\": {\"type\": \"minecraft:trapezoid\", \"min\": -3, \"max\": 3, \"plateau\": 0}}]")));
         return new WorldgenCatalog(WorldgenCatalog.FORMAT, "26.3", "fabric", 1L, "canopy", List.of(new CatalogNamespace("mod", "Mod", "1")),
                 biomes, features, List.of(), List.of(), List.of(), Map.of());
     }