@Override
    public TextureCubeMap getSpecularIBL() {
        return specular;
    }
Create a new IBL env baker
@param rm The render manager used to render the env scene
@param am The asset manager used to load the baking shaders
@param format  The format of the color buffers
@param depthFormat The format of the depth buffers
@param env_size The size in pixels of the output environment cube map (eg. 1024)
@param specular_size The size in pixels of the output specular cube map (eg. 1024)
@param irradiance_size The size in pixels of the output irradiance cube map (eg. 512)
@param brtf_size The size in pixels of the output brtf map (eg. 512)
jme3-core/src/main/java/com/jme3/environment/baker/IBLGLEnvBaker.java