Bat ponies and changelings can now wear saddlebags, but they use a built in texture for it

src/main/java/com/minelittlepony/client/model/gear/IRenderContext.java

@@ -6,6 +6,8 @@ import net.minecraft.util.Identifier;
 import com.minelittlepony.model.IModel;
 import com.minelittlepony.model.gear.IGear;
 
+import javax.annotation.Nullable;
+
 public interface IRenderContext<T extends Entity, M extends IModel> {
 
     IRenderContext<?, ?> NULL = (e, g) -> null;
@@ -14,5 +16,10 @@ public interface IRenderContext<T extends Entity, M extends IModel> {
         return gear.canRender(model, entity);
     }
 
+    @Nullable
+    default IModel getEntityModel() {
+        return null;
+    }
+
     Identifier getDefaultTexture(T entity, IGear gear);
 }

src/main/java/com/minelittlepony/client/model/gear/SaddleBags.java

@@ -4,6 +4,7 @@ import com.minelittlepony.client.util.render.plane.PlaneRenderer;
 import com.minelittlepony.model.BodyPart;
 import com.minelittlepony.model.IModel;
 import com.minelittlepony.model.IPegasus;
+import com.minelittlepony.pony.meta.Race;
 import com.minelittlepony.pony.meta.Wearable;
 import com.mojang.blaze3d.platform.GlStateManager;
 
@@ -15,6 +16,8 @@ import net.minecraft.util.math.MathHelper;
 
 public class SaddleBags extends AbstractGear {
 
+    public static final Identifier TEXTURE = new Identifier("minelittlepony", "textures/models/saddlebags.png");
+
     private PlaneRenderer leftBag;
     private PlaneRenderer rightBag;
 
@@ -137,7 +140,9 @@ public class SaddleBags extends AbstractGear {
 
     @Override
     public <T extends Entity> Identifier getTexture(T entity, IRenderContext<T, ?> context) {
+        if (context.getEntityModel() != null && context.getEntityModel().getMetadata().getRace().isEquivalentTo(Race.CHANGELING)) {
+            return TEXTURE;
+        }
         return context.getDefaultTexture(entity, this);
     }
-
 }

src/main/java/com/minelittlepony/client/model/races/ModelBatpony.java

@@ -5,7 +5,6 @@ import net.minecraft.entity.LivingEntity;
 import com.minelittlepony.client.model.components.BatWings;
 import com.minelittlepony.client.model.components.PonyEars;
 import com.minelittlepony.client.util.render.PonyRenderer;
-import com.minelittlepony.pony.meta.Wearable;
 
 public class ModelBatpony<T extends LivingEntity> extends ModelPegasus<T> {
 
@@ -23,13 +22,4 @@ public class ModelBatpony<T extends LivingEntity> extends ModelPegasus<T> {
         ears = new PonyEars(head, true);
         ears.init(yOffset, stretch);
     }
-
-    @Override
-    public boolean isWearing(Wearable wearable) {
-        if (wearable == Wearable.SADDLE_BAGS) {
-            return false;
-        }
-
-        return super.isWearing(wearable);
-    }
 }

src/main/java/com/minelittlepony/client/model/races/ModelChangeling.java

@@ -4,7 +4,6 @@ import net.minecraft.entity.LivingEntity;
 import net.minecraft.util.math.MathHelper;
 
 import com.minelittlepony.client.model.components.BugWings;
-import com.minelittlepony.pony.meta.Wearable;
 
 public class ModelChangeling<T extends LivingEntity> extends ModelAlicorn<T> {
 
@@ -29,13 +28,4 @@ public class ModelChangeling<T extends LivingEntity> extends ModelAlicorn<T> {
         }
         return WING_ROT_Z_SNEAK;
     }
-
-    @Override
-    public boolean isWearing(Wearable wearable) {
-        if (wearable == Wearable.SADDLE_BAGS) {
-            return false;
-        }
-
-        return super.isWearing(wearable);
-    }
 }

src/main/java/com/minelittlepony/client/render/entities/player/RenderPonyPlayer.java

@@ -3,6 +3,7 @@ package com.minelittlepony.client.render.entities.player;
 import com.minelittlepony.client.MineLittlePony;
 import com.minelittlepony.client.model.ClientPonyModel;
 import com.minelittlepony.client.model.ModelWrapper;
+import com.minelittlepony.client.model.gear.SaddleBags;
 import com.minelittlepony.client.render.DebugBoundingBoxRenderer;
 import com.minelittlepony.client.render.IPonyRender;
 import com.minelittlepony.client.render.RenderPony;
@@ -14,7 +15,9 @@ import com.minelittlepony.client.render.layer.LayerPonyArmor;
 import com.minelittlepony.client.render.layer.LayerPonyCape;
 import com.minelittlepony.client.render.layer.LayerPonyCustomHead;
 import com.minelittlepony.client.render.layer.LayerPonyElytra;
+import com.minelittlepony.model.gear.IGear;
 import com.minelittlepony.pony.IPony;
+import com.minelittlepony.pony.meta.Race;
 import com.mojang.blaze3d.platform.GlStateManager;
 
 import java.util.List;
@@ -186,4 +189,14 @@ public class RenderPonyPlayer extends PlayerEntityRenderer implements IPonyRende
         return MineLittlePony.getInstance().getManager().getPony(entity);
     }
 
+    @Override
+    public Identifier getDefaultTexture(AbstractClientPlayerEntity entity, IGear gear) {
+        if (gear == LayerGear.SADDLE_BAGS) {
+            if (getInternalRenderer().getModel().getMetadata().getRace() == Race.BATPONY) {
+                return SaddleBags.TEXTURE;
+            }
+        }
+
+        return IPonyRender.super.getDefaultTexture(entity, gear);
+    }
 }

src/main/java/com/minelittlepony/pony/meta/Race.java

@@ -87,6 +87,13 @@ public enum Race implements ITriggerPixelMapped<Race> {
         return getAlias() != this;
     }
 
+    /**
+     * Returns true if both races resolve to the same value.
+     */
+    public boolean isEquivalentTo(Race other) {
+        return getAlias() == other.getAlias();
+    }
+
     /**
      * Gets the actual race determined by the given pony level.
      * PonyLevel.HUMANS would force all races to be humans.