public void setShaderPrologue(String shaderPrologue) {
        this.shaderPrologue = shaderPrologue;
    }
Set a string which is prepended to every shader used by this technique.

Typically this is used for preset defines.

@param shaderPrologue The prologue to append before the technique's shaders.
jme3-core/src/main/java/com/jme3/material/TechniqueDef.java