One big happy family

- Add ModelTree
- Add LoweringVisitor to traverse a MeshTree and emit ModelTree nodes
  and Models
- Provide some default visitor creation methods
- Abstract ModelCache -> ResourceReloadCache
- Abstract ModelHolder -> ResourceReloadHolder
- Add ModelTreeCache to hide lookup cost if it gets extreme

common/src/lib/java/dev/engine_room/flywheel/lib/model/ModelCache.java

@@ -1,40 +1,11 @@
 package dev.engine_room.flywheel.lib.model;
 
-import java.util.Map;
-import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Function;
 
-import org.jetbrains.annotations.ApiStatus;
-
 import dev.engine_room.flywheel.api.model.Model;
-import dev.engine_room.flywheel.lib.util.FlwUtil;
-
-public final class ModelCache<T> {
-	private static final Set<ModelCache<?>> ALL = FlwUtil.createWeakHashSet();
-	private final Function<T, Model> factory;
-	private final Map<T, Model> map = new ConcurrentHashMap<>();
 
+public final class ModelCache<T> extends ResourceReloadCache<T, Model> {
 	public ModelCache(Function<T, Model> factory) {
-		this.factory = factory;
-
-		synchronized (ALL) {
-			ALL.add(this);
-		}
-	}
-
-	public Model get(T key) {
-		return map.computeIfAbsent(key, factory);
-	}
-
-	public void clear() {
-		map.clear();
-	}
-
-	@ApiStatus.Internal
-	public static void onEndClientResourceReload() {
-		for (ModelCache<?> cache : ALL) {
-			cache.clear();
-		}
+		super(factory);
 	}
 }

common/src/lib/java/dev/engine_room/flywheel/lib/model/ModelHolder.java

@@ -1,60 +1,11 @@
 package dev.engine_room.flywheel.lib.model;
 
-import java.util.Set;
 import java.util.function.Supplier;
 
-import org.jetbrains.annotations.ApiStatus;
-import org.jetbrains.annotations.Nullable;
-
 import dev.engine_room.flywheel.api.model.Model;
-import dev.engine_room.flywheel.lib.util.FlwUtil;
-
-public final class ModelHolder {
-	private static final Set<ModelHolder> ALL = FlwUtil.createWeakHashSet();
-	private final Supplier<Model> factory;
-	@Nullable
-	private volatile Model model;
 
+public final class ModelHolder extends ResourceReloadHolder<Model> {
 	public ModelHolder(Supplier<Model> factory) {
-		this.factory = factory;
-
-		synchronized (ALL) {
-			ALL.add(this);
-		}
-	}
-
-	public Model get() {
-		Model model = this.model;
-
-		if (model == null) {
-			synchronized (this) {
-				model = this.model;
-				if (model == null) {
-					this.model = model = factory.get();
-				}
-			}
-		}
-
-		return model;
-	}
-
-	public void clear() {
-		Model model = this.model;
-
-		if (model != null) {
-			synchronized (this) {
-				model = this.model;
-				if (model != null) {
-					this.model = null;
-				}
-			}
-		}
-	}
-
-	@ApiStatus.Internal
-	public static void onEndClientResourceReload() {
-		for (ModelHolder holder : ALL) {
-			holder.clear();
-		}
+		super(factory);
 	}
 }

common/src/lib/java/dev/engine_room/flywheel/lib/model/ResourceReloadCache.java

@@ -0,0 +1,44 @@
+package dev.engine_room.flywheel.lib.model;
+
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
+
+import org.jetbrains.annotations.ApiStatus;
+
+import dev.engine_room.flywheel.lib.util.FlwUtil;
+
+public class ResourceReloadCache<T, U> implements Function<T, U> {
+	private static final Set<ResourceReloadCache<?, ?>> ALL = FlwUtil.createWeakHashSet();
+	private final Function<T, U> factory;
+	private final Map<T, U> map = new ConcurrentHashMap<>();
+
+	public ResourceReloadCache(Function<T, U> factory) {
+		this.factory = factory;
+
+		synchronized (ALL) {
+			ALL.add(this);
+		}
+	}
+
+	public final U get(T key) {
+		return map.computeIfAbsent(key, factory);
+	}
+
+	@Override
+	public final U apply(T t) {
+		return get(t);
+	}
+
+	public final void clear() {
+		map.clear();
+	}
+
+	@ApiStatus.Internal
+	public static void onEndClientResourceReload() {
+		for (ResourceReloadCache<?, ?> cache : ALL) {
+			cache.clear();
+		}
+	}
+}

common/src/lib/java/dev/engine_room/flywheel/lib/model/ResourceReloadHolder.java

@@ -0,0 +1,60 @@
+package dev.engine_room.flywheel.lib.model;
+
+import java.util.Set;
+import java.util.function.Supplier;
+
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.Nullable;
+
+import dev.engine_room.flywheel.lib.util.FlwUtil;
+
+public class ResourceReloadHolder<T> implements Supplier<T> {
+	private static final Set<ResourceReloadHolder<?>> ALL = FlwUtil.createWeakHashSet();
+	private final Supplier<T> factory;
+	@Nullable
+	private volatile T obj;
+
+	public ResourceReloadHolder(Supplier<T> factory) {
+		this.factory = factory;
+
+		synchronized (ALL) {
+			ALL.add(this);
+		}
+	}
+
+	@Override
+	public final T get() {
+		T obj = this.obj;
+
+		if (obj == null) {
+			synchronized (this) {
+				obj = this.obj;
+				if (obj == null) {
+					this.obj = obj = factory.get();
+				}
+			}
+		}
+
+		return obj;
+	}
+
+	public final void clear() {
+		T obj = this.obj;
+
+		if (obj != null) {
+			synchronized (this) {
+				obj = this.obj;
+				if (obj != null) {
+					this.obj = null;
+				}
+			}
+		}
+	}
+
+	@ApiStatus.Internal
+	public static void onEndClientResourceReload() {
+		for (ResourceReloadHolder<?> holder : ALL) {
+			holder.clear();
+		}
+	}
+}

common/src/lib/java/dev/engine_room/flywheel/lib/model/part/InstanceTree.java

@@ -1,7 +1,6 @@
 package dev.engine_room.flywheel.lib.model.part;
 
 import java.util.NoSuchElementException;
-import java.util.function.BiFunction;
 import java.util.function.Consumer;
 import java.util.function.ObjIntConsumer;
 
@@ -15,23 +14,16 @@ import org.joml.Vector3fc;
 import com.mojang.blaze3d.vertex.PoseStack;
 
 import dev.engine_room.flywheel.api.instance.InstancerProvider;
-import dev.engine_room.flywheel.api.material.Material;
-import dev.engine_room.flywheel.api.model.Mesh;
 import dev.engine_room.flywheel.api.model.Model;
 import dev.engine_room.flywheel.lib.instance.InstanceTypes;
 import dev.engine_room.flywheel.lib.instance.TransformedInstance;
-import dev.engine_room.flywheel.lib.model.ModelCache;
-import dev.engine_room.flywheel.lib.model.SingleMeshModel;
 import dev.engine_room.flywheel.lib.transform.Affine;
 import dev.engine_room.flywheel.lib.transform.TransformStack;
-import net.minecraft.client.model.geom.ModelLayerLocation;
 import net.minecraft.client.model.geom.ModelPart;
 import net.minecraft.client.model.geom.PartPose;
 
 public final class InstanceTree {
-	private static final ModelCache<Model.ConfiguredMesh> MODEL_CACHE = new ModelCache<>(entry -> new SingleMeshModel(entry.mesh(), entry.material()));
-
-	private final MeshTree source;
+	private final ModelTree source;
 	@Nullable
 	private final TransformedInstance instance;
 	private final InstanceTree[] children;
@@ -54,7 +46,7 @@ public final class InstanceTree {
 
 	private boolean changed;
 
-	private InstanceTree(MeshTree source, @Nullable TransformedInstance instance, InstanceTree[] children) {
+	private InstanceTree(ModelTree source, @Nullable TransformedInstance instance, InstanceTree[] children) {
 		this.source = source;
 		this.instance = instance;
 		this.children = children;
@@ -68,21 +60,16 @@ public final class InstanceTree {
 		resetPose();
 	}
 
-	private static InstanceTree create(InstancerProvider provider, MeshTree meshTree, BiFunction<String, Mesh, Model.ConfiguredMesh> meshFinalizerFunc, String path) {
+	public static InstanceTree create(InstancerProvider provider, ModelTree meshTree) {
 		InstanceTree[] children = new InstanceTree[meshTree.childCount()];
-		String pathSlash = path + "/";
-
 		for (int i = 0; i < meshTree.childCount(); i++) {
-			var meshTreeChild = meshTree.child(i);
-			String name = meshTree.childName(i);
-			children[i] = create(provider, meshTreeChild, meshFinalizerFunc, pathSlash + name);
+			children[i] = create(provider, meshTree.child(i));
 		}
 
-		Mesh mesh = meshTree.mesh();
+		Model model = meshTree.model();
 		TransformedInstance instance;
-		if (mesh != null) {
-			Model.ConfiguredMesh configuredMesh = meshFinalizerFunc.apply(path, mesh);
-			instance = provider.instancer(InstanceTypes.TRANSFORMED, MODEL_CACHE.get(configuredMesh))
+		if (model != null) {
+			instance = provider.instancer(InstanceTypes.TRANSFORMED, model)
 					.createInstance();
 		} else {
 			instance = null;
@@ -91,22 +78,6 @@ public final class InstanceTree {
 		return new InstanceTree(meshTree, instance, children);
 	}
 
-	public static InstanceTree create(InstancerProvider provider, MeshTree meshTree, BiFunction<String, Mesh, Model.ConfiguredMesh> meshFinalizerFunc) {
-		return create(provider, meshTree, meshFinalizerFunc, "");
-	}
-
-	public static InstanceTree create(InstancerProvider provider, ModelLayerLocation layer, BiFunction<String, Mesh, Model.ConfiguredMesh> meshFinalizerFunc) {
-		return create(provider, MeshTree.of(layer), meshFinalizerFunc);
-	}
-
-	public static InstanceTree create(InstancerProvider provider, MeshTree meshTree, Material material) {
-		return create(provider, meshTree, (path, mesh) -> new Model.ConfiguredMesh(material, mesh));
-	}
-
-	public static InstanceTree create(InstancerProvider provider, ModelLayerLocation layer, Material material) {
-		return create(provider, MeshTree.of(layer), material);
-	}
-
 	@Nullable
 	public TransformedInstance instance() {
 		return instance;

common/src/lib/java/dev/engine_room/flywheel/lib/model/part/LoweringVisitor.java

@@ -0,0 +1,93 @@
+package dev.engine_room.flywheel.lib.model.part;
+
+import java.util.ArrayList;
+
+import org.jetbrains.annotations.Nullable;
+
+import dev.engine_room.flywheel.api.material.Material;
+import dev.engine_room.flywheel.api.model.Mesh;
+import dev.engine_room.flywheel.api.model.Model;
+import dev.engine_room.flywheel.lib.model.RetexturedMesh;
+import dev.engine_room.flywheel.lib.model.SingleMeshModel;
+import net.minecraft.client.model.geom.PartPose;
+import net.minecraft.client.renderer.texture.TextureAtlasSprite;
+
+/**
+ * A tree walking visitor that lowers a MeshTree to a ModelTree.
+ */
+public interface LoweringVisitor {
+	static ModelTree leaf(Model model) {
+		return leaf(model, PartPose.ZERO);
+	}
+
+	static ModelTree leaf(Model model, PartPose initialPose) {
+		return ModelTree.create(model, initialPose, new ModelTree[0], new String[0]);
+	}
+
+	static LoweringVisitor materialApplyingVisitor(Material material) {
+		return (path, mesh) -> new SingleMeshModel(mesh, material);
+	}
+
+	static LoweringVisitor retexturingVisitor(Material material, TextureAtlasSprite sprite) {
+		return (path, mesh) -> new SingleMeshModel(new RetexturedMesh(mesh, sprite), material);
+	}
+
+	static String append(String path, String child) {
+		if (path.isEmpty()) {
+			return child;
+		}
+
+		return path + "/" + child;
+	}
+
+	/**
+	 * Walk the given MeshTree, lowering its Mesh to a Model, and lowering all children using the given visitor.
+	 *
+	 * @param path            The absolute path to the MeshTree node.
+	 * @param meshTree        The MeshTree to walk.
+	 * @param loweringVisitor The visitor to use to lower the Mesh and MeshTree nodes.
+	 * @return The lowered ModelTree.
+	 */
+	static ModelTree walk(String path, MeshTree meshTree, LoweringVisitor loweringVisitor) {
+		Model out = null;
+
+		if (meshTree.mesh() != null) {
+			out = loweringVisitor.visit(path, meshTree.mesh());
+		}
+
+		ArrayList<ModelTree> children = new ArrayList<>();
+		ArrayList<String> childNames = new ArrayList<>();
+
+		for (int i = 0; i < meshTree.childCount(); i++) {
+			var child = loweringVisitor.visit(append(path, meshTree.childName(i)), meshTree.child(i));
+
+			if (child != null) {
+				children.add(child);
+				childNames.add(meshTree.childName(i));
+			}
+		}
+
+		return ModelTree.create(out, meshTree.initialPose(), children.toArray(new ModelTree[0]), childNames.toArray(new String[0]));
+	}
+
+	/**
+	 * Visit the given Mesh, converting it to a Model.
+	 *
+	 * @param path The absolute path to the MeshTree node containing the Mesh.
+	 * @param mesh The Mesh to lower.
+	 * @return The lowered Model, or null if the Model should be omitted.
+	 */
+	@Nullable Model visit(String path, Mesh mesh);
+
+	/**
+	 * Visit the given MeshTree, converting it to a ModelTree.
+	 *
+	 * @param path     The absolute path to the MeshTree node.
+	 * @param meshTree The MeshTree to lower.
+	 * @return The lowered ModelTree, or null if the ModelTree should be omitted.
+	 */
+	@Nullable
+	default ModelTree visit(String path, MeshTree meshTree) {
+		return walk(path, meshTree, this);
+	}
+}

common/src/lib/java/dev/engine_room/flywheel/lib/model/part/ModelTree.java

@@ -0,0 +1,107 @@
+package dev.engine_room.flywheel.lib.model.part;
+
+import java.util.Arrays;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.Nullable;
+
+import dev.engine_room.flywheel.api.model.Model;
+import net.minecraft.client.model.geom.ModelLayerLocation;
+import net.minecraft.client.model.geom.PartPose;
+
+public class ModelTree {
+	private static final Map<ModelTreeKey, ModelTree> CACHE = new ConcurrentHashMap<>();
+
+	@Nullable
+	private final Model model;
+	private final PartPose initialPose;
+	private final ModelTree[] children;
+	private final String[] childNames;
+
+	private ModelTree(@Nullable Model model, PartPose initialPose, ModelTree[] children, String[] childNames) {
+		this.model = model;
+		this.initialPose = initialPose;
+		this.children = children;
+		this.childNames = childNames;
+	}
+
+	/**
+	 * Create and memoize a ModelTree root.
+	 *
+	 * <p>This method is intended for use by Visuals.
+	 *
+	 * @param modelLayerLocation The model location to lower.
+	 * @param loweringVisitor    The visitor to use to lower the model.
+	 * @return The cached ModelTree root.
+	 */
+	public static ModelTree of(ModelLayerLocation modelLayerLocation, LoweringVisitor loweringVisitor) {
+		return CACHE.computeIfAbsent(new ModelTreeKey(modelLayerLocation, loweringVisitor), k -> {
+			var meshTree = MeshTree.of(k.modelLayerLocation());
+
+			var out = k.loweringVisitor()
+					.visit("", meshTree);
+
+			if (out == null) {
+				// Should this be an error, or a missing model?
+				return ModelTree.create(null, PartPose.ZERO, new ModelTree[0], new String[0]);
+			}
+
+			return out;
+		});
+	}
+
+	/**
+	 * Create a new ModelTree node.
+	 *
+	 * <p>This method is intended for use by {@link LoweringVisitor} implementations.
+	 *
+	 * @param model       The model to associate with this node, or null if this node does not render.
+	 * @param initialPose The initial pose of this node.
+	 * @param children    The children of this node.
+	 * @param childNames  The names of the children of this node.
+	 * @return A new ModelTree node.
+	 * @throws IllegalArgumentException if children and childNames have different lengths.
+	 */
+	public static ModelTree create(@Nullable Model model, PartPose initialPose, ModelTree[] children, String[] childNames) {
+		if (children.length != childNames.length) {
+			throw new IllegalArgumentException("children and childNames must have the same length (%s != %s)".formatted(children.length, childNames.length));
+		}
+
+		return new ModelTree(model, initialPose, children, childNames);
+	}
+
+	public int childCount() {
+		return children.length;
+	}
+
+	public ModelTree child(int index) {
+		return children[index];
+	}
+
+	public String childName(int index) {
+		return childNames[index];
+	}
+
+	public PartPose initialPose() {
+		return initialPose;
+	}
+
+	@Nullable
+	public Model model() {
+		return model;
+	}
+
+	public int childIndex(String name) {
+		return Arrays.binarySearch(childNames, name);
+	}
+
+	@ApiStatus.Internal
+	public static void onEndClientResourceReload() {
+		CACHE.clear();
+	}
+
+	private record ModelTreeKey(ModelLayerLocation modelLayerLocation, LoweringVisitor loweringVisitor) {
+	}
+}

common/src/lib/java/dev/engine_room/flywheel/lib/model/part/ModelTreeCache.java

@@ -0,0 +1,15 @@
+package dev.engine_room.flywheel.lib.model.part;
+
+import java.util.function.Function;
+
+import dev.engine_room.flywheel.lib.model.ResourceReloadCache;
+
+/**
+ * If the lookup to create your model tree directly through {@link ModelTree#of} is particularly expensive,
+ * you can memoize the arguments here to hide the cost.
+ */
+public class ModelTreeCache<T> extends ResourceReloadCache<T, ModelTree> {
+	public ModelTreeCache(Function<T, ModelTree> factory) {
+		super(factory);
+	}
+}

common/src/main/java/dev/engine_room/flywheel/vanilla/BellVisual.java

@@ -7,16 +7,16 @@ import org.joml.Matrix4fc;
 
 import dev.engine_room.flywheel.api.instance.Instance;
 import dev.engine_room.flywheel.api.material.Material;
-import dev.engine_room.flywheel.api.model.Model;
 import dev.engine_room.flywheel.api.visualization.VisualizationContext;
 import dev.engine_room.flywheel.lib.material.SimpleMaterial;
-import dev.engine_room.flywheel.lib.model.RetexturedMesh;
+import dev.engine_room.flywheel.lib.model.ResourceReloadHolder;
 import dev.engine_room.flywheel.lib.model.part.InstanceTree;
+import dev.engine_room.flywheel.lib.model.part.LoweringVisitor;
+import dev.engine_room.flywheel.lib.model.part.ModelTree;
 import dev.engine_room.flywheel.lib.visual.AbstractBlockEntityVisual;
 import dev.engine_room.flywheel.lib.visual.SimpleDynamicVisual;
 import net.minecraft.client.model.geom.ModelLayers;
 import net.minecraft.client.renderer.blockentity.BellRenderer;
-import net.minecraft.client.renderer.texture.TextureAtlasSprite;
 import net.minecraft.core.BlockPos;
 import net.minecraft.util.Mth;
 import net.minecraft.world.level.block.entity.BellBlockEntity;
@@ -26,6 +26,9 @@ public class BellVisual extends AbstractBlockEntityVisual<BellBlockEntity> imple
 			.mipmap(false)
 			.build();
 
+	// Need to hold the visitor in a ResourceReloadHolder to ensure we have a valid sprite.
+	private static final ResourceReloadHolder<LoweringVisitor> VISITOR = new ResourceReloadHolder<>(() -> LoweringVisitor.retexturingVisitor(MATERIAL, BellRenderer.BELL_RESOURCE_LOCATION.sprite()));
+
 	private final InstanceTree instances;
 	private final InstanceTree bellBody;
 
@@ -36,10 +39,7 @@ public class BellVisual extends AbstractBlockEntityVisual<BellBlockEntity> imple
 	public BellVisual(VisualizationContext ctx, BellBlockEntity blockEntity, float partialTick) {
 		super(ctx, blockEntity, partialTick);
 
-		TextureAtlasSprite sprite = BellRenderer.BELL_RESOURCE_LOCATION.sprite();
-		instances = InstanceTree.create(instancerProvider(), ModelLayers.BELL, (path, mesh) -> {
-			return new Model.ConfiguredMesh(MATERIAL, new RetexturedMesh(mesh, sprite));
-		});
+		instances = InstanceTree.create(instancerProvider(), ModelTree.of(ModelLayers.BELL, VISITOR.get()));
 		bellBody = instances.childOrThrow("bell_body");
 
 		BlockPos visualPos = getVisualPosition();

common/src/main/java/dev/engine_room/flywheel/vanilla/ChestVisual.java

@@ -4,6 +4,7 @@ import java.util.Calendar;
 import java.util.EnumMap;
 import java.util.Map;
 import java.util.function.Consumer;
+import java.util.function.Function;
 
 import org.jetbrains.annotations.Nullable;
 import org.joml.Matrix4f;
@@ -15,8 +16,11 @@ import dev.engine_room.flywheel.api.model.Model;
 import dev.engine_room.flywheel.api.visualization.VisualizationContext;
 import dev.engine_room.flywheel.lib.material.CutoutShaders;
 import dev.engine_room.flywheel.lib.material.SimpleMaterial;
-import dev.engine_room.flywheel.lib.model.RetexturedMesh;
+import dev.engine_room.flywheel.lib.model.ResourceReloadCache;
 import dev.engine_room.flywheel.lib.model.part.InstanceTree;
+import dev.engine_room.flywheel.lib.model.part.LoweringVisitor;
+import dev.engine_room.flywheel.lib.model.part.ModelTree;
+import dev.engine_room.flywheel.lib.transform.TransformStack;
 import dev.engine_room.flywheel.lib.visual.AbstractBlockEntityVisual;
 import dev.engine_room.flywheel.lib.visual.SimpleDynamicVisual;
 import it.unimi.dsi.fastutil.floats.Float2FloatFunction;
@@ -53,6 +57,8 @@ public class ChestVisual<T extends BlockEntity & LidBlockEntity> extends Abstrac
 		LAYER_LOCATIONS.put(ChestType.RIGHT, ModelLayers.DOUBLE_CHEST_RIGHT);
 	}
 
+	private static final Function<TextureAtlasSprite, LoweringVisitor> VISITOR = new ResourceReloadCache<>(s -> LoweringVisitor.retexturingVisitor(MATERIAL, s));
+
 	@Nullable
 	private final InstanceTree instances;
 	@Nullable
@@ -77,10 +83,7 @@ public class ChestVisual<T extends BlockEntity & LidBlockEntity> extends Abstrac
 		if (block instanceof AbstractChestBlock<?> chestBlock) {
 			ChestType chestType = blockState.hasProperty(ChestBlock.TYPE) ? blockState.getValue(ChestBlock.TYPE) : ChestType.SINGLE;
 			TextureAtlasSprite sprite = Sheets.chooseMaterial(blockEntity, chestType, isChristmas()).sprite();
-
-			instances = InstanceTree.create(instancerProvider(), LAYER_LOCATIONS.get(chestType), (path, mesh) -> {
-				return new Model.ConfiguredMesh(MATERIAL, new RetexturedMesh(mesh, sprite));
-			});
+			instances = InstanceTree.create(instancerProvider(), ModelTree.of(LAYER_LOCATIONS.get(chestType), VISITOR.apply(sprite)));
 			lid = instances.childOrThrow("lid");
 			lock = instances.childOrThrow("lock");
 

common/src/main/java/dev/engine_room/flywheel/vanilla/MinecartVisual.java

@@ -14,6 +14,8 @@ import dev.engine_room.flywheel.lib.instance.TransformedInstance;
 import dev.engine_room.flywheel.lib.material.SimpleMaterial;
 import dev.engine_room.flywheel.lib.model.Models;
 import dev.engine_room.flywheel.lib.model.part.InstanceTree;
+import dev.engine_room.flywheel.lib.model.part.LoweringVisitor;
+import dev.engine_room.flywheel.lib.model.part.ModelTree;
 import dev.engine_room.flywheel.lib.visual.ComponentEntityVisual;
 import dev.engine_room.flywheel.lib.visual.SimpleDynamicVisual;
 import dev.engine_room.flywheel.lib.visual.SimpleTickableVisual;
@@ -34,6 +36,7 @@ public class MinecartVisual<T extends AbstractMinecart> extends ComponentEntityV
 			.texture(TEXTURE)
 			.mipmap(false)
 			.build();
+	private static final LoweringVisitor VISITOR = LoweringVisitor.materialApplyingVisitor(MATERIAL);
 
 	private final InstanceTree instances;
 	@Nullable
@@ -47,7 +50,7 @@ public class MinecartVisual<T extends AbstractMinecart> extends ComponentEntityV
 	public MinecartVisual(VisualizationContext ctx, T entity, float partialTick, ModelLayerLocation layerLocation) {
 		super(ctx, entity, partialTick);
 
-		instances = InstanceTree.create(instancerProvider(), layerLocation, MATERIAL);
+		instances = InstanceTree.create(instancerProvider(), ModelTree.of(layerLocation, VISITOR));
 		blockState = entity.getDisplayBlockState();
 		contents = createContentsInstance();
 

fabric/src/main/java/dev/engine_room/flywheel/impl/FlywheelFabric.java

@@ -9,10 +9,11 @@ import dev.engine_room.flywheel.backend.LightSmoothnessArgument;
 import dev.engine_room.flywheel.backend.compile.FlwProgramsReloader;
 import dev.engine_room.flywheel.backend.engine.uniform.Uniforms;
 import dev.engine_room.flywheel.impl.visualization.VisualizationEventHandler;
-import dev.engine_room.flywheel.lib.model.ModelCache;
-import dev.engine_room.flywheel.lib.model.ModelHolder;
+import dev.engine_room.flywheel.lib.model.ResourceReloadCache;
+import dev.engine_room.flywheel.lib.model.ResourceReloadHolder;
 import dev.engine_room.flywheel.lib.model.baked.PartialModelEventHandler;
 import dev.engine_room.flywheel.lib.model.part.MeshTree;
+import dev.engine_room.flywheel.lib.model.part.ModelTree;
 import net.fabricmc.api.ClientModInitializer;
 import net.fabricmc.fabric.api.client.command.v2.ClientCommandRegistrationCallback;
 import net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientEntityEvents;
@@ -68,12 +69,11 @@ public final class FlywheelFabric implements ClientModInitializer {
 	}
 
 	private static void setupLib() {
-		EndClientResourceReloadCallback.EVENT.register((minecraft, resourceManager, initialReload, error) ->
-				ModelCache.onEndClientResourceReload());
-		EndClientResourceReloadCallback.EVENT.register((minecraft, resourceManager, initialReload, error) ->
-				ModelHolder.onEndClientResourceReload());
+		EndClientResourceReloadCallback.EVENT.register((minecraft, resourceManager, initialReload, error) -> ResourceReloadCache.onEndClientResourceReload());
+		EndClientResourceReloadCallback.EVENT.register((minecraft, resourceManager, initialReload, error) -> ResourceReloadHolder.onEndClientResourceReload());
 		EndClientResourceReloadCallback.EVENT.register((minecraft, resourceManager, initialReload, error) ->
 				MeshTree.onEndClientResourceReload());
+		EndClientResourceReloadCallback.EVENT.register((minecraft, resourceManager, initialReload, error) -> ModelTree.onEndClientResourceReload());
 
 		ModelLoadingPlugin.register(ctx -> {
 			ctx.addModels(PartialModelEventHandler.onRegisterAdditional());

forge/src/main/java/dev/engine_room/flywheel/impl/FlywheelForge.java

@@ -10,10 +10,11 @@ import dev.engine_room.flywheel.backend.LightSmoothnessArgument;
 import dev.engine_room.flywheel.backend.compile.FlwProgramsReloader;
 import dev.engine_room.flywheel.backend.engine.uniform.Uniforms;
 import dev.engine_room.flywheel.impl.visualization.VisualizationEventHandler;
-import dev.engine_room.flywheel.lib.model.ModelCache;
-import dev.engine_room.flywheel.lib.model.ModelHolder;
+import dev.engine_room.flywheel.lib.model.ResourceReloadCache;
+import dev.engine_room.flywheel.lib.model.ResourceReloadHolder;
 import dev.engine_room.flywheel.lib.model.baked.PartialModelEventHandler;
 import dev.engine_room.flywheel.lib.model.part.MeshTree;
+import dev.engine_room.flywheel.lib.model.part.ModelTree;
 import dev.engine_room.flywheel.lib.util.LevelAttached;
 import net.minecraft.client.Minecraft;
 import net.minecraft.commands.synchronization.ArgumentTypeInfos;
@@ -110,9 +111,10 @@ public final class FlywheelForge {
 	private static void registerLibEventListeners(IEventBus forgeEventBus, IEventBus modEventBus) {
 		forgeEventBus.addListener((LevelEvent.Unload e) -> LevelAttached.invalidateLevel(e.getLevel()));
 
-		modEventBus.addListener((EndClientResourceReloadEvent e) -> ModelCache.onEndClientResourceReload());
-		modEventBus.addListener((EndClientResourceReloadEvent e) -> ModelHolder.onEndClientResourceReload());
+		modEventBus.addListener((EndClientResourceReloadEvent e) -> ResourceReloadCache.onEndClientResourceReload());
+		modEventBus.addListener((EndClientResourceReloadEvent e) -> ResourceReloadHolder.onEndClientResourceReload());
 		modEventBus.addListener((EndClientResourceReloadEvent e) -> MeshTree.onEndClientResourceReload());
+		modEventBus.addListener((EndClientResourceReloadEvent e) -> ModelTree.onEndClientResourceReload());
 
 		modEventBus.addListener(PartialModelEventHandler::onRegisterAdditional);
 		modEventBus.addListener(PartialModelEventHandler::onBakingCompleted);