Merge pull request IrisShaders#1111 from maximumpower55/no-duplicate-…

…uniforms

Stop duplicated uniforms from being added

src/main/java/net/coderbot/iris/gl/program/ProgramUniforms.java

@@ -1,7 +1,12 @@
 package net.coderbot.iris.gl.program;
 
 import java.nio.IntBuffer;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.OptionalInt;
 
 import com.google.common.collect.ImmutableList;
 import com.mojang.blaze3d.platform.GlStateManager;
@@ -155,8 +160,14 @@ public OptionalInt location(String name, UniformType type) {
 				return OptionalInt.empty();
 			}
 
-			locations.put(id, name);
-			uniformNames.put(name, type);
+			if (!locations.containsKey(id) && !uniformNames.containsKey(name)) {
+				locations.put(id, name);
+				uniformNames.put(name, type);
+			} else {
+				Iris.logger.warn("[" + this.name + "] Duplicate uniform: " + type.toString().toLowerCase() + " " + name);
+
+				return OptionalInt.empty();
+			}
 
 			return OptionalInt.of(id);
 		}
@@ -252,6 +263,7 @@ public Builder addDynamicUniform(Uniform uniform, ValueUpdateNotifier notifier)
 		@Override
 		public UniformHolder externallyManagedUniform(String name, UniformType type) {
 			externalUniformNames.put(name, type);
+
 			return this;
 		}
 	}