Fix JSON model root transforms (#9410)

src/main/java/net/minecraftforge/client/model/CompositeModel.java

@@ -45,6 +45,7 @@ import net.minecraftforge.client.model.data.ModelProperty;
 import net.minecraftforge.client.model.geometry.IGeometryBakingContext;
 import net.minecraftforge.client.model.geometry.IGeometryLoader;
 import net.minecraftforge.client.model.geometry.IUnbakedGeometry;
+import net.minecraftforge.client.model.geometry.UnbakedGeometryHelper;
 import net.minecraftforge.common.util.ConcatenatedListView;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -88,7 +89,7 @@ public class CompositeModel implements IUnbakedGeometry<CompositeModel>
 
         var rootTransform = context.getRootTransform();
         if (!rootTransform.isIdentity())
-            modelState = new SimpleModelState(modelState.getRotation().compose(rootTransform), modelState.isUvLocked());
+            modelState = UnbakedGeometryHelper.composeRootTransformIntoModelState(modelState, rootTransform);
 
         var bakedPartsBuilder = ImmutableMap.<String, BakedModel>builder();
         for (var entry : children.entrySet())

src/main/java/net/minecraftforge/client/model/ElementsModel.java

@@ -5,32 +5,26 @@
 
 package net.minecraftforge.client.model;
 
-import com.google.common.collect.Sets;
 import com.google.gson.JsonDeserializationContext;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParseException;
-import com.mojang.datafixers.util.Pair;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.List;
-import java.util.Set;
 import java.util.function.Function;
 import net.minecraft.client.renderer.block.model.BlockElement;
-import net.minecraft.client.renderer.block.model.BlockElementFace;
 import net.minecraft.client.renderer.block.model.BlockModel;
-import net.minecraft.client.renderer.texture.MissingTextureAtlasSprite;
 import net.minecraft.client.renderer.texture.TextureAtlasSprite;
 import net.minecraft.client.resources.model.Material;
 import net.minecraft.client.resources.model.ModelBaker;
 import net.minecraft.client.resources.model.ModelState;
-import net.minecraft.client.resources.model.UnbakedModel;
 import net.minecraft.core.Direction;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.util.GsonHelper;
 import net.minecraftforge.client.model.geometry.IGeometryBakingContext;
 import net.minecraftforge.client.model.geometry.IGeometryLoader;
 import net.minecraftforge.client.model.geometry.SimpleUnbakedGeometry;
+import net.minecraftforge.client.model.geometry.UnbakedGeometryHelper;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -64,8 +58,10 @@ public class ElementsModel extends SimpleUnbakedGeometry<ElementsModel>
         // If there is a root transform, undo the ModelState transform, apply it, then re-apply the ModelState transform.
         // This is necessary because of things like UV locking, which should only respond to the ModelState, and as such
         // that is the only transform that should be applied during face bake.
-        var postTransform = context.getRootTransform().isIdentity() ? QuadTransformers.empty() :
-                QuadTransformers.applying(modelState.getRotation().compose(context.getRootTransform()).compose(modelState.getRotation().inverse()));
+        var postTransform = QuadTransformers.empty();
+        var rootTransform = context.getRootTransform();
+        if (!rootTransform.isIdentity())
+            postTransform = UnbakedGeometryHelper.applyRootTransform(modelState, rootTransform);
 
         for (BlockElement element : elements)
         {

src/main/java/net/minecraftforge/client/model/ItemLayerModel.java

@@ -72,7 +72,7 @@ public class ItemLayerModel implements IUnbakedGeometry<ItemLayerModel>
         );
         var rootTransform = context.getRootTransform();
         if (!rootTransform.isIdentity())
-            modelState = new SimpleModelState(modelState.getRotation().compose(rootTransform), modelState.isUvLocked());
+            modelState = UnbakedGeometryHelper.composeRootTransformIntoModelState(modelState, rootTransform);
 
         var normalRenderTypes = new RenderTypeGroup(RenderType.translucent(), ForgeRenderTypes.ITEM_UNSORTED_TRANSLUCENT.get());
         CompositeModel.Baked.Builder builder = CompositeModel.Baked.builder(context, particle, overrides, context.getTransforms());

src/main/java/net/minecraftforge/client/model/geometry/UnbakedGeometryHelper.java

@@ -29,6 +29,8 @@ import net.minecraft.resources.ResourceLocation;
 import net.minecraftforge.client.model.ElementsModel;
 import net.minecraftforge.client.model.ForgeFaceData;
 import net.minecraftforge.client.model.IModelBuilder;
+import net.minecraftforge.client.model.IQuadTransformer;
+import net.minecraftforge.client.model.QuadTransformers;
 import net.minecraftforge.client.model.SimpleModelState;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.Nullable;
@@ -268,4 +270,32 @@ public class UnbakedGeometryHelper
     {
         return FACE_BAKERY.bakeQuad(element.from, element.to, face, sprite, direction, state, element.rotation, element.shade, modelLocation);
     }
+
+    /**
+     * Create an {@link IQuadTransformer} to apply a {@link Transformation} that undoes the {@link ModelState}
+     * transform (blockstate transform), applies the given root transform and then re-applies the
+     * blockstate transform.
+     *
+     * @return an {@code IQuadTransformer} that applies the root transform to a baked quad that already has the
+     * transformation of the given {@code ModelState} applied to it
+     */
+    public static IQuadTransformer applyRootTransform(ModelState modelState, Transformation rootTransform)
+    {
+        // Move the origin of the ModelState transform and its inverse from the negative corner to the block center
+        // to replicate the way the ModelState transform is applied in the FaceBakery by moving the vertices such that
+        // the negative corner acts as the block center
+        Transformation transform = modelState.getRotation().applyOrigin(new Vector3f(.5F, .5F, .5F));
+        return QuadTransformers.applying(transform.compose(rootTransform).compose(transform.inverse()));
+    }
+
+    /**
+     * {@return a {@link ModelState} that combines the existing model state and the {@linkplain Transformation root transform}}
+     */
+    public static ModelState composeRootTransformIntoModelState(ModelState modelState, Transformation rootTransform)
+    {
+        // Move the origin of the root transform as if the negative corner were the block center to match the way the
+        // ModelState transform is applied in the FaceBakery by moving the vertices to be centered on that corner
+        rootTransform = rootTransform.applyOrigin(new Vector3f(-.5F, -.5F, -.5F));
+        return new SimpleModelState(modelState.getRotation().compose(rootTransform), modelState.isUvLocked());
+    }
 }

src/main/java/net/minecraftforge/common/util/TransformationHelper.java

@@ -212,16 +212,9 @@ public final class TransformationHelper
                 elements.remove("origin");
             }
             if (!elements.isEmpty()) throw new JsonParseException("TRSR: can either have single 'matrix' key, or a combination of 'translation', 'rotation' OR 'left_rotation', 'scale', 'post-rotation' (legacy) OR 'right_rotation', 'origin'. Found: " + String.join(", ", elements));
-            Transformation matrix = new Transformation(translation, leftRot, scale, rightRot);
 
-            // Use a different origin if needed.
-            if (!TransformOrigin.CENTER.getVector().equals(origin))
-            {
-                Vector3f originFromCenter = new Vector3f(origin);
-                originFromCenter.sub(TransformOrigin.CENTER.getVector());
-                matrix = matrix.applyOrigin(originFromCenter);
-            }
-            return matrix;
+            Transformation matrix = new Transformation(translation, leftRot, scale, rightRot);
+            return matrix.applyOrigin(new Vector3f(origin));
         }
 
         private static Vector3f parseOrigin(JsonObject obj) {