// Persistence of Vision Ray Tracer Include File
// File: gamma.inc
// Desc: gamma function approximation
//       part of waves.inc water wave simulation
// Date: November 2001
// Auth: Christoph Hormann <chris_hormann@gmx.de>

#declare GAMMA_ARR = array[1001] {
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362000.0 }

#macro Frac(Z)
  (Z - int(Z))
#end

#macro gamma(Z)

   #if ((Z>=0) & (Z<10))
      ( GAMMA_ARR[floor(Z*100)]*(1-Frac(Z*100)) +
        GAMMA_ARR[ceil(Z*100)]*Frac(Z*100) )
   #else
     362000.0 + 10*362000.0*(Z-10)
   #end
#end