<scene>

  <image>1 1</image>

  <sampler type="JitteredSampler">
    <numSamplesU>100</numSamplesU>
    <numSamplesV>100</numSamplesV>
  </sampler>

  <renderer type="KajiyaMediumPathTracer">
    <depthLimit>10</depthLimit>
    <backgroundIllumination>1</backgroundIllumination>
    <directIlluminator type="LuminairesIlluminator" />
  </renderer>
  <renderer type="DirectOnlyMediumRenderer">
    <directIlluminator type="LuminairesIlluminator" />
  </renderer>

  <!-- camera looking straight down -->
  <camera>
    <eye>0 500 0</eye>
    <!--eye>-866 500 0</eye-->  <!-- for 60 degrees -->
    <target>0 0 0</target>
    <up>0 0 1</up>
    <yFOV>0.1</yFOV>
  </camera>

  <!-- backdrop producing unit irradiance -->
  <surface type="Triangle">
    <material type="LambertianEmitter">
      <radiance>1 1 1</radiance>
    </material>
    <v0>   0   -1  500.0</v0>
    <v1> 433.0 -1 -250.0</v1>
    <v2>-433.0 -1 -250.0</v2>
  </surface>

  <!--
    A unit-thickness layer of absorbing medium.
    Radiance should be exp(-1/cos theta)
  -->

  <medium type="HomogeneousMedium">
    <minPt>-100 -1 -100</minPt>
    <maxPt>100 0 100</maxPt>
    <absorptionCoefficient>1 1 1</absorptionCoefficient>
  </medium>
</scene>
