more robust optifine detection

src/main/java/com/falsepattern/falsetweaks/asm/modules/occlusion/optifine/RenderGlobalDeOptimizer.java

@@ -32,8 +32,11 @@
 import org.objectweb.asm.tree.MethodInsnNode;
 import org.objectweb.asm.tree.TypeInsnNode;
 
+import net.minecraft.launchwrapper.Launch;
 import cpw.mods.fml.client.FMLClientHandler;
 import cpw.mods.fml.common.FMLCommonHandler;
+import cpw.mods.fml.common.Loader;
+import cpw.mods.fml.relauncher.FMLLaunchHandler;
 import cpw.mods.fml.relauncher.Side;
 
 /**
@@ -69,11 +72,36 @@ public boolean shouldTransformClass(@NotNull String className, @NotNull ClassNod
     }
 
     private static class LazyOptiFineCheck {
+        private static Boolean optifineDetected = null;
         private static boolean hasOptiFine() {
-            if (FMLCommonHandler.instance().getSide() == Side.CLIENT) {
-                return FMLClientHandler.instance().hasOptifine();
+            Boolean detected = optifineDetected;
+            if (detected == null) {
+                if (FMLLaunchHandler.side().isClient()) {
+                    try {
+                        //We might be too early but let's try the standard way
+                        detected = FMLClientHandler.instance().hasOptifine();
+                    } catch (Throwable ignored) {
+                        //Ok, we'll do it manually then
+                        try {
+                            ClassLoader cl;
+                            cl = Loader.instance().getModClassLoader();
+                            if (cl == null) {
+                                cl = Launch.classLoader;
+                            }
+                            Class.forName("Config", false, cl);
+                            detected = true;
+                        } catch (Throwable ignored1) {
+                            //99.9% sure that optifine is not present
+                            detected = false;
+                        }
+                    }
+                } else {
+                    //server shouldn't have OF
+                    detected = false;
+                }
+                optifineDetected = detected;
             }
-            return false;
+            return detected;
         }
     }