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#ifndef MONO_CHANNEL_GLSLLIB
#define MONO_CHANNEL_GLSLLIB

#ifdef QT3DS_DEFINE_API
#define mono_alpha 0
#define mono_average 1
#define mono_luminance 2
#define mono_maximum 3
#endif

float monoChannel( in vec4 t, in int monoSource )
{
  switch( monoSource )
  {
    case mono_alpha :
      return( t.w );
    case mono_average :
      return( ( t.x + t.y + t.z ) / 3.0 );
    case mono_luminance :
      return( luminance( t.xyz ) );
    case mono_maximum :
      return( max( t.x, max( t.y, t.z ) ) );
    default :
      return( 1.0 );
  }
}

#endif