protected String replaceVariableName(String nodeSource, ShaderNodeVariable var) {
        String namePrefix = getAppendableNameSpace(var);
        String newName = namePrefix + var.getName();
        nodeSource = replace(nodeSource, var, newName);
        return nodeSource;
    }
replaces a variable name in a shaderNode source code by prefixing it
with its nameSpace and "_" if needed.
@param nodeSource the source to modify
@param var the variable to replace
@return the modified source
jme3-core/src/main/java/com/jme3/shader/Glsl100ShaderGenerator.java