Halo Event Handler

package halocraft;

import java.util.Collection;
import java.util.Iterator;

import org.lwjgl.opengl.GL11;

import net.minecraft.client.Minecraft;
import net.minecraft.client.gui.Gui;
import net.minecraft.client.gui.ScaledResolution;
import net.minecraft.client.renderer.Tessellator;
import net.minecraft.client.renderer.WorldRenderer;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.ItemStack;
import net.minecraft.potion.Potion;
import net.minecraft.potion.PotionEffect;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.client.event.RenderGameOverlayEvent;
import net.minecraftforge.client.event.RenderGameOverlayEvent.ElementType;
import net.minecraftforge.fml.common.eventhandler.EventPriority;
import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
import net.minecraftforge.fml.common.gameevent.TickEvent.RenderTickEvent;

public class HaloEventHandler extends Gui{
    private Minecraft mc;
    ResourceLocation res = new ResourceLocation("halocraft:textures/gui/HaloOverlay.png");
     public HaloEventHandler(Minecraft mc){
        super();
        // We need this to invoke the render engine.
        this.mc = mc;
      }
     /**
         * Draws textured rectangles of sizes other than 256x256
         * @param x The x value of the top-left corner point on the screen where drawing to starts
         * @param y The y value of the top-left corner point on the screen where drawing to starts
         * @param u The u (x) value of top-left corner point of the texture to start drawing from
         * @param v The v (y) value of top-left corner point of the texture to start drawing from
         * @param width The width of the rectangle to draw on screen
         * @param height The height of the rectangle to draw on screen
         * @param textureWidth The width of the whole texture
         * @param textureHeight The height of the whole texture
         */
        protected void drawNonStandardTexturedRect(int x, int y, int u, int v, int width, int height, int textureWidth, int textureHeight)
        {
            double f = 1F / (double)textureWidth;
            double f1 = 1F / (double)textureHeight;
            WorldRenderer tessellator = Tessellator.getInstance().getWorldRenderer();
            tessellator.startDrawingQuads();
            tessellator.addVertexWithUV(x, y + height, 0, u * f, (v + height) * f1);
            tessellator.addVertexWithUV(x + width, y + height, 0, (u + width) * f, (v + height) * f1);
            tessellator.addVertexWithUV(x + width, y, 0, (u + width) * f, v * f1);
            tessellator.addVertexWithUV(x, y, 0, u * f, v * f1);
            Tessellator.getInstance().draw();
        }
        private static final int BUFF_ICON_SIZE = 256;
        @SubscribeEvent(priority = EventPriority.NORMAL)
        public void onRenderGameOverlay(RenderGameOverlayEvent event)
        {
            if(event.isCancelable() || event.type != ElementType.EXPERIENCE){
                return;
            }
            //if (((EntityPlayer)mc.thePlayer).inventory.armorInventory[3].getItem() == halocraft.Main.SpartanHelmet){
                int xPos = 0;
                int yPos = 0;
                GL11.glColor4f(1.0F, 1.0F, 1.0F, 1.0F);
                GL11.glDisable(GL11.GL_LIGHTING);
                this.mc.renderEngine.bindTexture(res);
                ScaledResolution Scaled = new ScaledResolution(mc, mc.displayWidth, mc.displayHeight);
                this.drawNonStandardTexturedRect(xPos, yPos, 0, 0, mc.displayWidth, mc.displayHeight, 420, 250);
            //}
     }
}