Reduce and reuse

- Create subclass to recycle PoseStack.Pose objects
- Add mixin/liblink to access a PoseStack's inner deque

common/src/lib/java/dev/engine_room/flywheel/lib/internal/FlwLibLink.java

@@ -1,5 +1,6 @@
 package dev.engine_room.flywheel.lib.internal;
 
+import java.util.Deque;
 import java.util.Map;
 
 import org.slf4j.Logger;
@@ -21,4 +22,6 @@ public interface FlwLibLink {
 	Map<String, ModelPart> getModelPartChildren(ModelPart part);
 
 	void compileModelPart(ModelPart part, PoseStack.Pose pose, VertexConsumer consumer, int light, int overlay, float red, float green, float blue, float alpha);
+
+	Deque<PoseStack.Pose> getPoseStack(PoseStack stack);
 }

common/src/lib/java/dev/engine_room/flywheel/lib/util/RecyclingPoseStack.java

@@ -0,0 +1,42 @@
+package dev.engine_room.flywheel.lib.util;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+
+import dev.engine_room.flywheel.lib.internal.FlwLibLink;
+
+/**
+ * A {@link PoseStack} that recycles {@link PoseStack.Pose} objects.
+ *
+ * <p>Vanilla's {@link PoseStack} can get quite expensive to use when each game object needs to
+ * maintain their own stack. This class helps alleviate memory pressure by making Pose objects
+ * long-lived. Note that this means that you <em>CANNOT</em> safely store a Pose object outside
+ * the RecyclingPoseStack that created it.
+ */
+public class RecyclingPoseStack extends PoseStack {
+	private final Deque<Pose> recycleBin = new ArrayDeque<>();
+
+	@Override
+	public void pushPose() {
+		if (recycleBin.isEmpty()) {
+			super.pushPose();
+		} else {
+			var last = last();
+			var recycle = recycleBin.pop();
+			recycle.pose()
+					.set(last.pose());
+			recycle.normal()
+					.set(last.normal());
+			FlwLibLink.INSTANCE.getPoseStack(this)
+					.addLast(recycle);
+		}
+	}
+
+	@Override
+	public void popPose() {
+		recycleBin.push(FlwLibLink.INSTANCE.getPoseStack(this)
+				.removeLast());
+	}
+}

common/src/main/java/dev/engine_room/flywheel/impl/FlwLibLinkImpl.java

@@ -1,5 +1,6 @@
 package dev.engine_room.flywheel.impl;
 
+import java.util.Deque;
 import java.util.Map;
 
 import org.slf4j.Logger;
@@ -9,6 +10,7 @@ import com.mojang.blaze3d.vertex.VertexConsumer;
 
 import dev.engine_room.flywheel.impl.extension.PoseStackExtension;
 import dev.engine_room.flywheel.impl.mixin.ModelPartAccessor;
+import dev.engine_room.flywheel.impl.mixin.PoseStackAccessor;
 import dev.engine_room.flywheel.lib.internal.FlwLibLink;
 import dev.engine_room.flywheel.lib.transform.PoseTransformStack;
 import net.minecraft.client.model.geom.ModelPart;
@@ -33,4 +35,9 @@ public class FlwLibLinkImpl implements FlwLibLink {
 	public void compileModelPart(ModelPart part, PoseStack.Pose pose, VertexConsumer consumer, int light, int overlay, float red, float green, float blue, float alpha) {
 		((ModelPartAccessor) (Object) part).flywheel$compile(pose, consumer, light, overlay, red, green, blue, alpha);
 	}
+
+	@Override
+	public Deque<PoseStack.Pose> getPoseStack(PoseStack stack) {
+		return ((PoseStackAccessor) stack).flywheel$getPoseStack();
+	}
 }

common/src/main/java/dev/engine_room/flywheel/impl/mixin/PoseStackAccessor.java

@@ -0,0 +1,14 @@
+package dev.engine_room.flywheel.impl.mixin;
+
+import java.util.Deque;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Accessor;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+
+@Mixin(PoseStack.class)
+public interface PoseStackAccessor {
+	@Accessor("poseStack")
+	Deque<PoseStack.Pose> flywheel$getPoseStack();
+}

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

@@ -18,6 +18,7 @@ import dev.engine_room.flywheel.lib.material.SimpleMaterial;
 import dev.engine_room.flywheel.lib.model.RetexturedMesh;
 import dev.engine_room.flywheel.lib.model.part.InstanceTree;
 import dev.engine_room.flywheel.lib.transform.TransformStack;
+import dev.engine_room.flywheel.lib.util.RecyclingPoseStack;
 import dev.engine_room.flywheel.lib.visual.AbstractBlockEntityVisual;
 import dev.engine_room.flywheel.lib.visual.SimpleDynamicVisual;
 import it.unimi.dsi.fastutil.floats.Float2FloatFunction;
@@ -59,7 +60,7 @@ public class ChestVisual<T extends BlockEntity & LidBlockEntity> extends Abstrac
 	@Nullable
 	private final InstanceTree lock;
 
-	private final PoseStack poseStack = new PoseStack();
+	private final PoseStack poseStack = new RecyclingPoseStack();
 	private final BrightnessCombiner brightnessCombiner = new BrightnessCombiner();
 	@Nullable
 	private final DoubleBlockCombiner.NeighborCombineResult<? extends ChestBlockEntity> neighborCombineResult;

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

@@ -16,6 +16,7 @@ import dev.engine_room.flywheel.lib.model.ModelHolder;
 import dev.engine_room.flywheel.lib.model.Models;
 import dev.engine_room.flywheel.lib.model.SingleMeshModel;
 import dev.engine_room.flywheel.lib.model.part.ModelPartConverter;
+import dev.engine_room.flywheel.lib.util.RecyclingPoseStack;
 import dev.engine_room.flywheel.lib.visual.ComponentEntityVisual;
 import dev.engine_room.flywheel.lib.visual.SimpleDynamicVisual;
 import dev.engine_room.flywheel.lib.visual.SimpleTickableVisual;
@@ -52,7 +53,7 @@ public class MinecartVisual<T extends AbstractMinecart> extends ComponentEntityV
 
 	private final ModelHolder bodyModel;
 
-	private final PoseStack stack = new PoseStack();
+	private final PoseStack stack = new RecyclingPoseStack();
 
 	private BlockState blockState;
 	private boolean active;

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

@@ -17,6 +17,7 @@ import dev.engine_room.flywheel.lib.model.ModelCache;
 import dev.engine_room.flywheel.lib.model.SingleMeshModel;
 import dev.engine_room.flywheel.lib.model.part.ModelPartConverter;
 import dev.engine_room.flywheel.lib.transform.TransformStack;
+import dev.engine_room.flywheel.lib.util.RecyclingPoseStack;
 import dev.engine_room.flywheel.lib.visual.AbstractBlockEntityVisual;
 import dev.engine_room.flywheel.lib.visual.SimpleDynamicVisual;
 import net.minecraft.client.model.geom.ModelLayers;
@@ -45,7 +46,7 @@ public class ShulkerBoxVisual extends AbstractBlockEntityVisual<ShulkerBoxBlockE
 	private final TransformedInstance base;
 	private final TransformedInstance lid;
 
-	private final PoseStack stack = new PoseStack();
+	private final PoseStack stack = new RecyclingPoseStack();
 
 	private float lastProgress = Float.NaN;
 

common/src/main/resources/flywheel.impl.mixins.json

@@ -13,6 +13,7 @@
     "LevelRendererMixin",
     "MinecraftMixin",
     "ModelPartAccessor",
+    "PoseStackAccessor",
     "PoseStackMixin",
     "fix.FixFabulousDepthMixin",
     "fix.FixNormalScalingMixin",