OpenGL ItemRenderer for Minecraft Forge 1.8!

ItemRendererManager.java

import java.util.ArrayList;
import java.util.List;

import net.minecraft.client.Minecraft;
import net.minecraft.item.Item;
import net.minecraftforge.client.event.ModelBakeEvent;
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.relauncher.SideOnly;

/**
 * @author Gliby, contact@gliby.net
 * 
 * Manages raw item renderer's.
 */
@SideOnly(Side.CLIENT)
public class ItemRendererManager {

	/**
	 * Should be created on FMLInitializationEvent event, everything takes care
	 * of it's self.
	 */
	public ItemRendererManager() {
		MinecraftForge.EVENT_BUS.register(this);
	}

	List<RawItemRenderer> itemRenderer = new ArrayList<RawItemRenderer>();

	public void registerItemRenderer(RawItem item, RawItemRenderer itemRender) {
		this.itemRenderer.add(itemRender);
		item.setRenderer(itemRender);
		Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(item, 0, itemRender.resourceLocation);
	}

	@SubscribeEvent
	public void bakeModel(ModelBakeEvent event) {
		for (int i = 0; i < itemRenderer.size(); i++) {
			RawItemRenderer itemRender = itemRenderer.get(i);
			event.modelRegistry.putObject(itemRender.resourceLocation, itemRender);

		}
	}
}

Mod.java

import net.gliby.physics.Physics;
import net.gliby.physics.client.render.entity.RenderPhysicsBlock;
import net.gliby.physics.client.render.entity.RenderPhysicsModelPart;
import net.gliby.physics.client.render.entity.RenderPhysicsRagdoll;
import net.gliby.physics.client.render.items.RenderItemPhysicsGun;
import net.gliby.physics.client.render.player.RenderAdditionalPlayer;
import net.gliby.physics.client.render.world.RenderAdditionalWorld;
import net.gliby.physics.common.entity.EntityPhysicsBlock;
import net.gliby.physics.common.entity.EntityPhysicsModelPart;
import net.gliby.physics.common.entity.EntityPhysicsRagdoll;
import net.minecraft.client.Minecraft;
import net.minecraft.client.renderer.block.model.ItemCameraTransforms;
import net.minecraft.client.renderer.entity.RenderItem;
import net.minecraft.client.resources.model.ModelResourceLocation;
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.fml.client.registry.RenderingRegistry;
import net.minecraftforge.fml.common.event.FMLInitializationEvent;

/**
 * This isn't an actual @Mod class, just an example. THIS ACTUAL CLASS IS NOT MEANT TO COMPILE!
 */
public class Mod {

	/**
	 * Called on Forge's init event, found inside @Mod interface.
	 * 
	 * @param event
	 */
	@EventHandler
	public void eventInit(FMLInitializationEvent event) {
		ItemRendererManager itemRenderManager = new ItemRendererManager();

		//Create fake-model resource, doesn't need any file to function.
		ModelResourceLocation modelID = new ModelResourceLocation(Physics.MOD_ID, "physicsgun");
		//Create actual RawItemRenderer instance, simply a class that "extends RawItemRenderer".
		RenderItemPhysicsGun renderRawPhysicsGun = new RenderItemPhysicsGun(modelID);
		//Register and bind to raw item!
		itemRenderManager.registerItemRenderer(Physics.itemPhysicsGun, renderRawPhysicsGun);
	}
}

RawItem.java

import RawItemRenderer;
import net.minecraft.entity.Entity;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.world.World;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.relauncher.SideOnly;

/**
 * 
 * @author Gliby, contact@gliby.net
 *
 */
public abstract class RawItem extends Item {

	@SideOnly(Side.CLIENT)
	public RawItemRenderer renderer;

	@SideOnly(Side.CLIENT)
	public net.minecraft.client.resources.model.ModelResourceLocation getModel(ItemStack stack, EntityPlayer player, int useRemaining) {
		this.renderer.setOwner(player);
		return super.getModel(stack, player, useRemaining);
	}

	/**
	 * @param itemRender
	 */
	public void setRenderer(RawItemRenderer itemRender) {
		this.renderer = itemRender;
	}
}

RawItemRenderer.java

import java.util.Collections;
import java.util.List;

import javax.vecmath.Matrix4f;

import org.apache.commons.lang3.tuple.Pair;

import net.minecraft.client.Minecraft;
import net.minecraft.client.entity.AbstractClientPlayer;
import net.minecraft.client.entity.EntityPlayerSP;
import net.minecraft.client.model.ModelBiped;
import net.minecraft.client.renderer.GlStateManager;
import net.minecraft.client.renderer.Tessellator;
import net.minecraft.client.renderer.WorldRenderer;
import net.minecraft.client.renderer.block.model.ItemCameraTransforms;
import net.minecraft.client.renderer.block.model.ItemCameraTransforms.TransformType;
import net.minecraft.client.renderer.entity.RenderItem;
import net.minecraft.client.renderer.texture.TextureAtlasSprite;
import net.minecraft.client.renderer.texture.TextureManager;
import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
import net.minecraft.client.renderer.vertex.VertexFormat;
import net.minecraft.client.resources.model.IBakedModel;
import net.minecraft.client.resources.model.ModelResourceLocation;
import net.minecraft.entity.Entity;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.ItemStack;
import net.minecraft.util.EnumFacing;
import net.minecraft.util.MathHelper;
import net.minecraftforge.client.ForgeHooksClient;
import net.minecraftforge.client.model.IFlexibleBakedModel;
import net.minecraftforge.client.model.IPerspectiveAwareModel;
import net.minecraftforge.client.model.ISmartItemModel;

/**
 * Based on iChunUtil's own item renderer, but with a some of my own spice. 
 * # Usage: 
 * # Simply extend this class, then register with ItemRendererManager!
 */
public abstract class RawItemRenderer implements ISmartItemModel, IPerspectiveAwareModel, IFlexibleBakedModel {

	protected EntityPlayer owner;

	protected TextureManager textureManager;
	public ModelResourceLocation resourceLocation;

	private Pair<IBakedModel, Matrix4f> pair;
	protected ModelBiped playerBiped = new ModelBiped();
	protected Minecraft mc;

	public RawItemRenderer(ModelResourceLocation resourceLocation) {
		this.mc = Minecraft.getMinecraft();
		this.textureManager = mc.getTextureManager();
		this.resourceLocation = resourceLocation;
		this.pair = Pair.of((IBakedModel) this, null);
		this.playerBiped = new ModelBiped();
		this.playerBiped.textureWidth = 64;
		this.playerBiped.textureHeight = 64;
	}

	public abstract void render();

	@Override
	public final List getGeneralQuads() {
		// Method that this get's called in, is using startDrawingQuads. We
		// finish
		// drawing it so we can move on to render our own thing.
		Tessellator tessellator = Tessellator.getInstance();
		WorldRenderer worldrenderer = tessellator.getWorldRenderer();
		tessellator.draw();
		GlStateManager.pushMatrix();
		GlStateManager.translate(0.5F, 0.5F, 0.5F);
		GlStateManager.scale(-1.0F, -1.0F, 1.0F);

		if (owner != null) {
			if (transformType == TransformType.THIRD_PERSON) {
				if (owner.isSneaking()) GlStateManager.translate(0.0F, -0.2F, 0.0F);
			}
		}

		if (onGround()) {
			GlStateManager.scale(-3f, -3f, -3f);
		}

		render();
		GlStateManager.popMatrix();
		// Reset the dynamic values.
		this.owner = null;
		this.stack = null;
		this.transformType = null;
		// Method that this gets called is expecting that we are still using
		// startDrawingQuads.
		worldrenderer.startDrawingQuads();
		return Collections.EMPTY_LIST;
	}

	protected boolean onGround() {
		return transformType == null;
	}

	@Override
	public List getFaceQuads(EnumFacing p_177551_1_) {
		return Collections.EMPTY_LIST;
	}

	@Override
	public final boolean isAmbientOcclusion() {
		return true;
	}

	@Override
	public final boolean isGui3d() {
		return true;
	}

	@Override
	public final boolean isBuiltInRenderer() {
		return false;
	}

	@Override
	public final TextureAtlasSprite getTexture() {
		return Minecraft.getMinecraft().getTextureMapBlocks().getMissingSprite();
	}

	@Override
	public abstract ItemCameraTransforms getItemCameraTransforms();

	protected ItemStack stack;

	@Override
	public IBakedModel handleItemState(ItemStack stack) {
		this.stack = stack;
		return this;
	}

	public void setOwner(EntityPlayer player) {
		this.owner = player;
	}

	protected TransformType transformType;

	@Override
	public Pair<IBakedModel, Matrix4f> handlePerspective(TransformType cameraTransformType) {
		this.transformType = cameraTransformType;
		switch (cameraTransformType) {
		case FIRST_PERSON:
			RenderItem.applyVanillaTransform(getItemCameraTransforms().firstPerson);
			break;
		case GUI:
			RenderItem.applyVanillaTransform(getItemCameraTransforms().gui);
			break;
		case HEAD:
			RenderItem.applyVanillaTransform(getItemCameraTransforms().head);
			break;
		case THIRD_PERSON:
			RenderItem.applyVanillaTransform(getItemCameraTransforms().thirdPerson);
			break;
		default:
			break;
		}
		return pair;
	}
}