Fix shader buffer block managment

Author: riccardobl

jme3-core/src/main/java/com/jme3/material/Material.java

@@ -848,13 +848,13 @@ private void updateShaderMaterialParameter(Renderer renderer, VarType type, Shad
             if (type == VarType.ShaderStorageBufferObject) {
                 btype = ShaderBufferBlock.BufferType.ShaderStorageBufferObject;
                 bufferBlock.setBufferObject(btype, bufferObject);
-                renderer.setShaderStorageBufferObject(unit.bufferUnit++, bufferObject);
+                renderer.setShaderStorageBufferObject(unit.bufferUnit, bufferObject); // TODO: probably not needed
             } else {
                 btype = ShaderBufferBlock.BufferType.UniformBufferObject;
                 bufferBlock.setBufferObject(btype, bufferObject);
-                renderer.setUniformBufferObject(unit.bufferUnit++, bufferObject);
+                renderer.setUniformBufferObject(unit.bufferUnit, bufferObject); // TODO: probably not needed
             }
-
+            unit.bufferUnit++;
         } else {
             Uniform uniform = shader.getUniform(param.getPrefixedName());
             if (!override && uniform.isSetByCurrentMaterial()) return;

jme3-core/src/main/java/com/jme3/shader/ShaderBufferBlock.java

@@ -63,6 +63,7 @@ public void setBufferObject(BufferType type, BufferObject bufferObject) {
         if (bufferObject == null) {
             throw new IllegalArgumentException("for storage block " + name + ": storageData cannot be null");
         }
+        if (bufferObject == this.bufferObject && type == this.type) return;
         this.bufferObject = bufferObject;
         this.bufferObjectRef = new WeakReference<BufferObject>(bufferObject);
         this.type = type;