CatServer/patches/net/minecraft/inventory/Slot.java.patch

--- ../src-base/minecraft/net/minecraft/inventory/Slot.java
+++ ../src-work/minecraft/net/minecraft/inventory/Slot.java
@@ -8,7 +8,7 @@
 
 public class Slot
 {
-    private final int slotIndex;
+    public final int slotIndex; // CatServer - private -> public
     public final IInventory inventory;
     public int slotNumber;
     public int xPos;
@@ -90,7 +90,7 @@
     @SideOnly(Side.CLIENT)
     public String getSlotTexture()
     {
-        return null;
+        return backgroundName;
     }
 
     public ItemStack decrStackSize(int amount)
@@ -113,4 +113,74 @@
     {
         return true;
     }
+
+    /*========================================= FORGE START =====================================*/
+    protected String backgroundName = null;
+    protected net.minecraft.util.ResourceLocation backgroundLocation = null;
+    protected Object backgroundMap;
+    /**
+     * Gets the path of the texture file to use for the background image of this slot when drawing the GUI.
+     * @return The resource location for the background image
+     */
+    @SideOnly(Side.CLIENT)
+    public net.minecraft.util.ResourceLocation getBackgroundLocation()
+    {
+        return (backgroundLocation == null ? net.minecraft.client.renderer.texture.TextureMap.LOCATION_BLOCKS_TEXTURE : backgroundLocation);
+    }
+
+    /**
+     * Sets the texture file to use for the background image of the slot when it's empty.
+     * @param texture the resourcelocation for the texture
+     */
+    @SideOnly(Side.CLIENT)
+    public void setBackgroundLocation(net.minecraft.util.ResourceLocation texture)
+    {
+        this.backgroundLocation = texture;
+    }
+
+    /**
+     * Sets which icon index to use as the background image of the slot when it's empty.
+     * @param name The icon to use, null for none
+     */
+    public void setBackgroundName(@Nullable String name)
+    {
+        this.backgroundName = name;
+    }
+
+    @Nullable
+    @SideOnly(Side.CLIENT)
+    public net.minecraft.client.renderer.texture.TextureAtlasSprite getBackgroundSprite()
+    {
+        String name = getSlotTexture();
+        return name == null ? null : getBackgroundMap().getAtlasSprite(name);
+    }
+
+    @SideOnly(Side.CLIENT)
+    protected net.minecraft.client.renderer.texture.TextureMap getBackgroundMap()
+    {
+        if (backgroundMap == null) backgroundMap = net.minecraft.client.Minecraft.getMinecraft().getTextureMapBlocks();
+        return (net.minecraft.client.renderer.texture.TextureMap)backgroundMap;
+    }
+
+    /**
+     * Retrieves the index in the inventory for this slot, this value should typically not
+     * be used, but can be useful for some occasions.
+     *
+     * @return Index in associated inventory for this slot.
+     */
+    public int getSlotIndex()
+    {
+        return slotIndex;
+    }
+
+    /**
+     * Checks if the other slot is in the same inventory, by comparing the inventory reference.
+     * @param other
+     * @return true if the other slot is in the same inventory
+     */
+    public boolean isSameInventory(Slot other)
+    {
+        return this.inventory == other.inventory;
+    }
+    /*========================================= FORGE END =====================================*/
 }