// The following problem occurs in:
//   POV-Ray for Windows v3.5 RC1 under
//   Windows 98 on Intel 700 with 128 megs Ram

// The scene demonstrates a phenomenon that occurs when radiosity
// is used with fade-to-transparancy in a color_map.
// It seems that at some point in the fade (in this example where the
// transmit value reaches 2/3), the fade is disrupted and resumes with
// a brighter value.
// The increase is even visible when the light source is commented out.

light_source { <-10, 20, -10> 1 }

camera {
  location <0, 3, -2>
  direction z
  right x*4/3
  look_at z
}

#local rad=true;
//#local rad=false;

global_settings {
  assumed_gamma 1
  #if (rad)
    radiosity { }
    ambient_light 0
  #end
}

#local P_P = rgbt <0, 0.1, 0>;
#local P_X = rgbt <P_P.x, P_P.y, P_P.z, 1>;
#local T_Fade = texture {
  pigment {
    gradient x
    color_map {
      [ 0 P_P ]
      [ 0.5 P_X ]
      [ 1 P_P  ]
    }
  }
}

plane { y, 0 texture { T_Fade } }

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