Fix #16 by using a mixin on the item renderer instead of trying to recreate it myself.

src/main/java/com/minelittlepony/ducks/IRenderItem.java

@@ -0,0 +1,6 @@
+package com.minelittlepony.ducks;
+
+public interface IRenderItem {
+
+    void useTransparency(boolean use);
+}

src/main/java/com/minelittlepony/mixin/MixinRenderItem.java

@@ -0,0 +1,43 @@
+package com.minelittlepony.mixin;
+
+import com.minelittlepony.ducks.IRenderItem;
+import net.minecraft.client.renderer.GlStateManager;
+import net.minecraft.client.renderer.RenderItem;
+import net.minecraft.client.resources.IResourceManagerReloadListener;
+import org.spongepowered.asm.mixin.Implements;
+import org.spongepowered.asm.mixin.Interface;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+@Mixin(value = RenderItem.class)
+@Implements( value = @Interface(iface = IRenderItem.class, prefix = "mlp$") )
+public abstract class MixinRenderItem implements IResourceManagerReloadListener, IRenderItem {
+
+    private static final String ItemStack = "Lnet/minecraft/item/ItemStack;";
+    private static final String IBakedModel = "Lnet/minecraft/client/renderer/block/model/IBakedModel;";
+    private static final String ItemCameraTransform$TransformType = "Lnet/minecraft/client/renderer/block/model/ItemCameraTransforms$TransformType;";
+    private static final String GlStateManager$SourceFactor = "Lnet/minecraft/client/renderer/GlStateManager$SourceFactor;";
+    private static final String GlStateManager$DestFactor = "Lnet/minecraft/client/renderer/GlStateManager$DestFactor;";
+
+    private boolean transparency;
+
+    public void mlp$useTransparency(boolean transparency) {
+        this.transparency = transparency;
+    }
+
+    @Redirect(method = "renderItemModel(" + ItemStack + IBakedModel + ItemCameraTransform$TransformType + "Z)V",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/client/renderer/GlStateManager;tryBlendFuncSeparate("
+                            + GlStateManager$SourceFactor + GlStateManager$DestFactor
+                            + GlStateManager$SourceFactor + GlStateManager$DestFactor + ")V"))
+    private void redirectBlendFunc(GlStateManager.SourceFactor srcFactor, GlStateManager.DestFactor dstFactor,
+                                   GlStateManager.SourceFactor srcFactorAlpha, GlStateManager.DestFactor dstFactorAlpha) {
+        if (transparency) {
+            GlStateManager.tryBlendFuncSeparate(GlStateManager.SourceFactor.CONSTANT_COLOR, GlStateManager.DestFactor.ONE, GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO);
+        } else {
+            GlStateManager.tryBlendFuncSeparate(GlStateManager.SourceFactor.SRC_ALPHA, GlStateManager.DestFactor.ONE_MINUS_SRC_ALPHA, GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO);
+        }
+    }
+}

src/main/java/com/minelittlepony/mixin/MixinRenderPlayer.java

@@ -23,6 +23,7 @@ import net.minecraft.client.renderer.entity.RenderPlayer;
 import net.minecraft.client.renderer.entity.layers.LayerArrow;
 import net.minecraft.util.ResourceLocation;
 import org.objectweb.asm.Opcodes;
+import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Shadow;
 import org.spongepowered.asm.mixin.injection.At;
@@ -37,6 +38,7 @@ import static net.minecraft.client.renderer.GlStateManager.scale;
 public abstract class MixinRenderPlayer extends RenderLivingBase<AbstractClientPlayer> implements IRenderPony {
 
     @Shadow
+    @Final
     private boolean smallArms;
     private PlayerModel playerModel;
     private Pony thePony;

src/main/java/com/minelittlepony/model/UnicornHorn.java

@@ -1,8 +1,6 @@
 package com.minelittlepony.model;
 
 import com.minelittlepony.PonyData;
-import com.minelittlepony.model.AbstractPonyModel;
-import com.minelittlepony.model.PonyModelConstants;
 import com.minelittlepony.renderer.HornGlowRenderer;
 import net.minecraft.client.model.ModelBase;
 import net.minecraft.client.model.ModelBiped.ArmPose;
@@ -51,7 +49,7 @@ public class UnicornHorn extends ModelBase implements PonyModelConstants {
                 float red = (data.getGlowColor() >> 16 & 255) / 255.0F;
                 float green = (data.getGlowColor() >> 8 & 255) / 255.0F;
                 float blue = (data.getGlowColor() & 255) / 255.0F;
-                blendFunc(GL11.GL_SRC_ALPHA, 1);
+                blendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE);
 
                 this.horn.postRender(scale);
 

src/main/java/com/minelittlepony/renderer/layer/LayerHeldPonyItem.java

@@ -1,6 +1,7 @@
 package com.minelittlepony.renderer.layer;
 
 import com.minelittlepony.PonyData;
+import com.minelittlepony.ducks.IRenderItem;
 import com.minelittlepony.ducks.IRenderPony;
 import com.minelittlepony.model.AbstractPonyModel;
 import com.minelittlepony.model.BodyPart;
@@ -12,7 +13,6 @@ import net.minecraft.client.model.ModelBiped;
 import net.minecraft.client.model.ModelRenderer;
 import net.minecraft.client.renderer.GlStateManager;
 import net.minecraft.client.renderer.RenderItem;
-import net.minecraft.client.renderer.block.model.IBakedModel;
 import net.minecraft.client.renderer.block.model.ItemCameraTransforms;
 import net.minecraft.client.renderer.entity.RenderLivingBase;
 import net.minecraft.client.renderer.entity.layers.LayerHeldItem;
@@ -20,7 +20,6 @@ import net.minecraft.client.renderer.entity.layers.LayerRenderer;
 import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.EnumHandSide;
-import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL14;
 
 import static net.minecraft.client.renderer.GlStateManager.*;
@@ -119,35 +118,29 @@ public class LayerHeldPonyItem implements LayerRenderer<EntityLivingBase> {
         if (drop2.hasEffect())
             drop2.setTagInfo("ench", null);
 
-        GL11.glPushAttrib(GL11.GL_CURRENT_BIT | GL11.GL_ENABLE_BIT | GL11.GL_COLOR_BUFFER_BIT);
-
         float red = (glowColor >> 16 & 255) / 255.0F;
         float green = (glowColor >> 8 & 255) / 255.0F;
         float blue = (glowColor & 255) / 255.0F;
         float alpha = 0.2F;
-        // disableLighting();
+
-        enableBlend();
+        pushMatrix();
-        blendFunc(GL11.GL_CONSTANT_COLOR, 1);
+        disableLighting();
+
         GL14.glBlendColor(red, green, blue, alpha);
 
         RenderItem renderItem = Minecraft.getMinecraft().getRenderItem();
-        IBakedModel model = renderItem.getItemModelWithOverrides(drop, entity.world, entity);
+        ((IRenderItem)renderItem).useTransparency(true);
-
-        ItemCameraTransforms itemcameratransforms = model.getItemCameraTransforms();
-        ItemCameraTransforms.applyTransformSide(itemcameratransforms.getTransform(transform), hand == EnumHandSide.LEFT);
 
         scale(1.1, 1.1, 1.1);
 
         translate(0, .01, .01);
-        renderItem.renderItem(drop2, model);
+        renderItem.renderItem(drop, entity, transform, hand == EnumHandSide.LEFT);
         translate(.01, -.01, -.02);
-        // scale(1.1, 1.1, 1.1);
+        renderItem.renderItem(drop, entity, transform, hand == EnumHandSide.LEFT);
-        renderItem.renderItem(drop2, model);
 
-        disableBlend();
+        ((IRenderItem)renderItem).useTransparency(false);
         enableLighting();
-        enableTexture2D();
+        popMatrix();
-        popAttrib();
 
         // I hate rendering
     }