Add Special Icons to Side Buttons for Inventory

src/main/java/noppes/npcs/client/gui/player/inventory/GuiCNPCInventory.java

@@ -1,6 +1,7 @@
 package noppes.npcs.client.gui.player.inventory;
 
 import net.minecraft.client.Minecraft;
+import net.minecraft.init.Items;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.ResourceLocation;
 import noppes.npcs.CustomItems;
@@ -12,6 +13,8 @@ import tconstruct.client.tabs.TabRegistry;
 
 public class GuiCNPCInventory extends GuiNPCInterface {
     private final ResourceLocation resource = new ResourceLocation("customnpcs","textures/gui/standardbg.png");
+    public static final ResourceLocation specialIcons = new ResourceLocation("customnpcs","textures/gui/icons.png");
+
     public static int activeTab = 0;
     private Minecraft mc = Minecraft.getMinecraft();
 
@@ -26,25 +29,38 @@ public class GuiCNPCInventory extends GuiNPCInterface {
         super.initGui();
         guiTop +=10;
 
-        GuiMenuSideButton questsButton = new GuiMenuSideButton(100, guiLeft + xSize + 37, this.guiTop + 3, 22, 22, "");
+        int y = 3;
+        GuiMenuSideButton questsButton = new GuiMenuSideButton(100, guiLeft + xSize + 37, this.guiTop + y, 22, 22, "");
         questsButton.rightSided = true;
         questsButton.active = activeTab == 0;
-        questsButton.renderStack = new ItemStack(CustomItems.letter);
+        questsButton.renderIconPosX = 32;
+        questsButton.renderResource = specialIcons;
         addButton(questsButton);
 
-        GuiMenuSideButton partyButton = new GuiMenuSideButton(101, guiLeft + xSize + 37, this.guiTop + 3 + 21, 22, 22, "");
+        y += 21;
+        GuiMenuSideButton partyButton = new GuiMenuSideButton(101, guiLeft + xSize + 37, this.guiTop + y, 22, 22, "");
         partyButton.rightSided = true;
         partyButton.active = activeTab == 1;
-        partyButton.renderStack = new ItemStack(CustomItems.bag);
+        partyButton.renderResource = specialIcons;
         addButton(partyButton);
 
         if(ConfigClient.enableFactionTab){
-            GuiMenuSideButton factionButton = new GuiMenuSideButton(102, guiLeft + xSize + 37, this.guiTop + 3 + 21*2, 22, 22, "");
+            y += 21;
+            GuiMenuSideButton factionButton = new GuiMenuSideButton(102, guiLeft + xSize + 37, this.guiTop + y, 22, 22, "");
             factionButton.rightSided = true;
             factionButton.active = activeTab == 2;
-            factionButton.renderStack = new ItemStack(CustomItems.wallBanner);
+            factionButton.renderIconPosX = 48;
+            factionButton.renderResource = specialIcons;
             addButton(factionButton);
         }
+
+        y += 21;
+        GuiMenuSideButton clientButton = new GuiMenuSideButton(101, guiLeft + xSize + 37, this.guiTop + y, 22, 22, "");
+        clientButton.rightSided = true;
+        clientButton.active = activeTab == 3;
+        clientButton.renderIconPosX = 16;
+        clientButton.renderResource = specialIcons;
+        addButton(clientButton);
     }
 
     @Override

src/main/java/noppes/npcs/client/gui/util/GuiMenuSideButton.java

@@ -6,6 +6,7 @@ import net.minecraft.client.renderer.RenderHelper;
 import net.minecraft.client.renderer.entity.RenderItem;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.ResourceLocation;
+import noppes.npcs.client.gui.player.inventory.GuiCNPCInventory;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL12;
 
@@ -16,6 +17,9 @@ public class GuiMenuSideButton extends GuiNpcButton{
     public boolean active;
     public boolean rightSided;
     public ItemStack renderStack;
+    public ResourceLocation renderResource;
+    public int renderIconPosX = 0;
+    public int renderIconPosY = 0;
 
     public GuiMenuSideButton(int id, int x, int y, String s){
         this(id, x, y, 200, 20, s);
@@ -54,6 +58,15 @@ public class GuiMenuSideButton extends GuiNpcButton{
         }
         mouseDragged(minecraft, i, j);
 
+        // Render Custom Icon
+        if (this.renderResource != null) {
+            this.zLevel = 100.0F;
+            minecraft.renderEngine.bindTexture(renderResource);
+            drawTexturedModalRect(xPosition + 2, yPosition + height/2 - 8, renderIconPosX, renderIconPosY, 16, 16);
+            this.zLevel = 0.0F;
+        }
+
+
         if (this.renderStack != null) {
             RenderHelper.enableGUIStandardItemLighting();
             this.zLevel = 100.0F;
@@ -71,7 +84,7 @@ public class GuiMenuSideButton extends GuiNpcButton{
             this.zLevel = 0.0F;
             RenderHelper.disableStandardItemLighting();
         }
-        
+
         String text = "";
         float maxWidth = width * 0.75f;
         if(fontrenderer.getStringWidth(displayString) > maxWidth){
@@ -102,7 +115,7 @@ public class GuiMenuSideButton extends GuiNpcButton{
 
     @Override
     public void mouseReleased(int i, int j){
-    	
+
     }
 
     @Override