Fix chest flickering when a barrel is in sight (#33)

* fix chest flickering

* refactor which should not change anything

src/main/java/mcp/mobius/betterbarrels/client/render/SurfaceItemRenderHelper.java

@@ -0,0 +1,30 @@
+package mcp.mobius.betterbarrels.client.render;
+
+import java.nio.FloatBuffer;
+
+import net.minecraft.client.renderer.GLAllocation;
+
+import org.lwjgl.opengl.GL11;
+
+/**
+ * RenderHelper but no directional light setting
+ */
+public class SurfaceItemRenderHelper {
+
+    private static final FloatBuffer ambientColorBuffer = (FloatBuffer) GLAllocation.createDirectFloatBuffer(16)
+            .put(0.4f).put(0.4f).put(0.4f).put(1.0f).flip();
+    private static final FloatBuffer cachedAmbientColor = GLAllocation.createDirectFloatBuffer(16);
+
+    public static void disableStandardItemLighting() {
+        GL11.glDisable(GL11.GL_COLOR_MATERIAL);
+        GL11.glLightModel(GL11.GL_LIGHT_MODEL_AMBIENT, cachedAmbientColor);
+    }
+
+    public static void enableStandardItemLighting() {
+        GL11.glEnable(GL11.GL_COLOR_MATERIAL);
+        GL11.glColorMaterial(GL11.GL_FRONT_AND_BACK, GL11.GL_AMBIENT_AND_DIFFUSE);
+        GL11.glShadeModel(GL11.GL_FLAT);
+        GL11.glGetFloat(GL11.GL_LIGHT_MODEL_AMBIENT, cachedAmbientColor);
+        GL11.glLightModel(GL11.GL_LIGHT_MODEL_AMBIENT, ambientColorBuffer);
+    }
+}

src/main/java/mcp/mobius/betterbarrels/client/render/SurfaceItemRenderer.java

@@ -5,7 +5,6 @@
 import net.minecraft.client.gui.FontRenderer;
 import net.minecraft.client.renderer.OpenGlHelper;
 import net.minecraft.client.renderer.RenderBlocks;
-import net.minecraft.client.renderer.RenderHelper;
 import net.minecraft.client.renderer.Tessellator;
 import net.minecraft.client.renderer.entity.RenderItem;
 import net.minecraft.client.renderer.texture.TextureManager;
@@ -142,7 +141,7 @@ private void renderGlint(int x, int y, int w, int h) {
 
     private void renderItemIntoGUIBlock(FontRenderer fontRenderer, TextureManager texManager, ItemStack itemStack,
             int x, int y, boolean renderEffect) {
-        RenderHelper.enableGUIStandardItemLighting();
+        SurfaceItemRenderHelper.enableStandardItemLighting();
         GL11.glDisable(GL11.GL_LIGHTING);
 
         texManager.bindTexture(TextureMap.locationBlocksTexture);
@@ -186,6 +185,6 @@ private void renderItemIntoGUIBlock(FontRenderer fontRenderer, TextureManager te
 
         GL11.glPopMatrix();
 
-        RenderHelper.disableStandardItemLighting();
+        SurfaceItemRenderHelper.disableStandardItemLighting();
     }
 }