Add custom texture pack support

src/main/java/moe/nea/firmament/mixins/MixinItemModels.java

@@ -0,0 +1,27 @@
+package moe.nea.firmament.mixins;
+
+import moe.nea.firmament.events.CustomItemModelEvent;
+import net.minecraft.client.render.item.ItemModels;
+import net.minecraft.client.render.model.BakedModel;
+import net.minecraft.client.render.model.BakedModelManager;
+import net.minecraft.item.ItemStack;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+@Mixin(ItemModels.class)
+public class MixinItemModels {
+    @Shadow
+    @Final
+    private BakedModelManager modelManager;
+
+    @Inject(method = "getModel(Lnet/minecraft/item/ItemStack;)Lnet/minecraft/client/render/model/BakedModel;", at = @At("HEAD"), cancellable = true)
+    public void onGetModel(ItemStack stack, CallbackInfoReturnable<BakedModel> cir) {
+        var model = CustomItemModelEvent.getModel(stack, modelManager);
+        if (model != null)
+            cir.setReturnValue(model);
+    }
+}

src/main/java/moe/nea/firmament/mixins/MixinModelLoader.java

@@ -0,0 +1,44 @@
+package moe.nea.firmament.mixins;
+
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.render.model.ModelLoader;
+import net.minecraft.client.render.model.UnbakedModel;
+import net.minecraft.client.texture.Sprite;
+import net.minecraft.client.util.ModelIdentifier;
+import net.minecraft.client.util.SpriteIdentifier;
+import net.minecraft.resource.Resource;
+import net.minecraft.util.Identifier;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import java.util.Map;
+import java.util.function.BiFunction;
+
+@Mixin(ModelLoader.class)
+public abstract class MixinModelLoader {
+
+    @Shadow
+    protected abstract void addModel(ModelIdentifier modelId);
+
+    @Shadow
+    @Final
+    private Map<Identifier, UnbakedModel> modelsToBake;
+
+    @Shadow
+    public abstract UnbakedModel getOrLoadModel(Identifier id);
+
+    @Inject(method = "bake", at = @At("HEAD"))
+    public void onBake(BiFunction<Identifier, SpriteIdentifier, Sprite> spriteLoader, CallbackInfo ci) {
+        Map<Identifier, Resource> resources =
+            MinecraftClient.getInstance().getResourceManager().findResources("models/item", it -> "firmskyblock".equals(it.getNamespace()) && it.getPath().endsWith(".json"));
+        for (Identifier identifier : resources.keySet()) {
+            ModelIdentifier modelId = new ModelIdentifier("firmskyblock", identifier.getPath().substring("models/item/".length(), identifier.getPath().length() - ".json".length()), "inventory");
+            addModel(modelId);
+        }
+        modelsToBake.values().forEach(model -> model.setParents(this::getOrLoadModel));
+    }
+}