Pattern Rendering and other Rendering

src/main/java/appeng/hooks/BlockToolDispenseItemBehavior.java

@@ -42,7 +42,7 @@ public final class BlockToolDispenseItemBehavior extends ItemDispenserBehavior {
             if (w instanceof ServerWorld) {
                 ItemUsageContext context = new AutomaticItemPlacementContext(w, dispenser.getBlockPos().offset(direction),
                         direction, dispensedItem, direction.getOpposite());
-                tm.onItemUse(context);
+                tm.useOnBlock(context);
             }
         }
         return dispensedItem;

src/main/java/appeng/hooks/IBlockTool.java

@@ -23,6 +23,6 @@ import net.minecraft.util.ActionResult;
 
 public interface IBlockTool {
     // Workaround for dispenser logic.
-    ActionResult onItemUse(ItemUsageContext itemUseContext);
+    ActionResult useOnBlock(ItemUsageContext itemUseContext);
 
 }

src/main/java/appeng/hooks/ItemRendererHooks.java

@@ -0,0 +1,48 @@
+package appeng.hooks;
+
+import appeng.items.misc.EncodedPatternItem;
+import appeng.mixins.ItemRendererAccessor;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.gui.screen.Screen;
+import net.minecraft.client.render.item.ItemRenderer;
+import net.minecraft.client.render.model.BakedModel;
+import net.minecraft.client.world.ClientWorld;
+import net.minecraft.item.ItemStack;
+
+public final class ItemRendererHooks {
+
+    // Prevents recursion in the hook below
+    private static final ThreadLocal<ItemStack> OVERRIDING_FOR = new ThreadLocal<>();
+
+    private ItemRendererHooks() {
+    }
+
+    /**
+     * This hook will exchange the rendered item model for encoded patterns to the item being crafted by them
+     * if shift is held.
+     */
+    public static boolean onRenderGuiItemModel(ItemRenderer renderer, ItemStack stack, int x, int y, BakedModel model) {
+        if (stack.getItem() instanceof EncodedPatternItem && OVERRIDING_FOR.get() != stack) {
+            boolean shiftHeld = Screen.hasShiftDown();
+            ClientWorld world = MinecraftClient.getInstance().world;
+            if (shiftHeld && world != null) {
+                EncodedPatternItem iep = (EncodedPatternItem) stack.getItem();
+                ItemStack output = iep.getOutput(world, stack);
+                if (!output.isEmpty()) {
+                    BakedModel realModel = MinecraftClient.getInstance().getItemRenderer().getModels()
+                            .getModel(output);
+                    ItemRendererAccessor self = (ItemRendererAccessor) renderer;
+                    OVERRIDING_FOR.set(stack);
+                    try {
+                        self.callRenderGuiItemModel(stack, x, y, realModel);
+                    } finally {
+                        OVERRIDING_FOR.remove();
+                    }
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+}