Fabric 1.17 does not contain the ArmorRenderingRegistry. Temporarily added the missing files to a shadow-namespace to allw testing of the CrystaliteArmor.

src/main/java/shadow/fabric/mixin/client/rendering/MixinItem.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+ /*
+ This file is a refactor from fabric-api, based on the work of shedaniel.
+ */
+
+package shadow.fabric.mixin.client.rendering;
+
+
+import net.minecraft.world.item.Item;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+import shadow.fabric.api.client.rendering.v1.ArmorRenderingRegistry;
+import shadow.fabric.impl.client.rendering.ArmorProviderExtensions;
+
+
+@Mixin(Item.class)
+public class MixinItem implements ArmorProviderExtensions {
+    @Unique
+    private ArmorRenderingRegistry.ModelProvider armorModelProvider;
+    @Unique
+    private ArmorRenderingRegistry.TextureProvider armorTextureProvider;
+
+    @Override
+    public ArmorRenderingRegistry.ModelProvider fabric_getArmorModelProvider() {
+        return armorModelProvider;
+    }
+
+    @Override
+    public ArmorRenderingRegistry.TextureProvider fabric_getArmorTextureProvider() {
+        return armorTextureProvider;
+    }
+
+    @Override
+    public void fabric_setArmorModelProvider(ArmorRenderingRegistry.ModelProvider provider) {
+        armorModelProvider = provider;
+    }
+
+    @Override
+    public void fabric_setArmorTextureProvider(ArmorRenderingRegistry.TextureProvider provider) {
+        armorTextureProvider = provider;
+    }
+}