Fixed compatibility with recent 1.7.10 Optifine versions

- Added the getLocalVarIndex method to look for the correct index (necessary since Optifine changed it along with names in E7)
- Replaced the static 14 index with the dynamic "var14" (or "frustrum") one inside the if checks
- Upped the version number to 1.4.1

Basically ported what i did with Betweenlands so it works with any version of Optifine or even without it. Again, huge thanks to makamys for helping me understand how variable adresses work.

build.gradle

@@ -17,7 +17,7 @@ buildscript {
 
 apply plugin: 'forge'
 
-version = "1.4.0"
+version = "1.4.1"
 group= "com.pau101.fairylights"
 archivesBaseName = "fairylights"
 

src/main/java/com/pau101/fairylights/core/FairyLightsClassTransformer.java

@@ -8,13 +8,7 @@
 import org.objectweb.asm.ClassReader;
 import org.objectweb.asm.ClassWriter;
 import org.objectweb.asm.Opcodes;
-import org.objectweb.asm.tree.AbstractInsnNode;
-import org.objectweb.asm.tree.ClassNode;
-import org.objectweb.asm.tree.FieldInsnNode;
-import org.objectweb.asm.tree.FieldNode;
-import org.objectweb.asm.tree.InsnList;
-import org.objectweb.asm.tree.MethodNode;
-import org.objectweb.asm.tree.VarInsnNode;
+import org.objectweb.asm.tree.*;
 
 public class FairyLightsClassTransformer implements IClassTransformer {
 	private Logger logger = Logger.getLogger("FairyLightsClassTransformer");
@@ -46,9 +40,25 @@ public byte[] transform(String name, String transformedName, byte[] basicClass)
 		return basicClass;
 	}
 
+	private int getLocalVarIndex(List<LocalVariableNode> list, String name, String name2) {
+		// Returns the index of a specific local variable name from the method. This is required for compatibility with any Optifine version.
+		// It uses a list which you can create in the specific method using method.localVariables, and two names since for some dumb reasons,
+		// The game can access varX fine with the latest Optifine but not the internal name, and the opposite otherwise.
+
+		for (int i = 0; i < list.size(); i += 1) {
+			LocalVariableNode object = list.get(i);
+			if (object.name.equals(name) || object.name.equals(name2)) return object.index;
+		}
+		return -1;
+
+	}
+
 	private boolean transformFrustumStore(boolean obf, List<MethodNode> methods, String entityRendererOwner, String frustumDesc) {
 		boolean replacedASTORE8 = false;
 		for (MethodNode method : methods) {
+			List localVarList = method.localVariables;
+			int var14index = getLocalVarIndex(localVarList, "var14", "frustrum");
+
 			if ("(FJ)V".equals(method.desc)) {
 				InsnList instructions = method.instructions;
 				for (int i = 0; i < instructions.size(); i++) {
@@ -57,15 +67,16 @@ private boolean transformFrustumStore(boolean obf, List<MethodNode> methods, Str
 						// replace all things trying to get the frustum from the
 						// stack frame to getting the frustum from the class
 						// field
-						if (instruction.getOpcode() == Opcodes.ALOAD && ((VarInsnNode) instruction).var == 14) {
+						if (instruction.getOpcode() == Opcodes.ALOAD && ((VarInsnNode) instruction).var == var14index) {
 							((VarInsnNode) instruction).var = 0;
 							instructions.insert(instruction, new FieldInsnNode(Opcodes.GETFIELD, entityRendererOwner, fieldNameAddition, frustumDesc));
 						}
+
 					} else {
 						// instead of storing the newly created frustum into
 						// slot 14 of the method stack frame, put in the added
 						// class field for external access
-						if (instruction.getOpcode() == Opcodes.ASTORE && ((VarInsnNode) instruction).var == 14) {
+						if (instruction.getOpcode() == Opcodes.ASTORE && ((VarInsnNode) instruction).var == var14index) {
 							InsnList newInsn = new InsnList();
 							instructions.insertBefore(instructions.get(i - 3), new VarInsnNode(Opcodes.ALOAD, 0));
 							instructions.set(instruction, new FieldInsnNode(Opcodes.PUTFIELD, entityRendererOwner, fieldNameAddition, frustumDesc));