text: 
  /*
      pbrt source code is Copyright(c) 1998-2016
                          Matt Pharr, Greg Humphreys, and Wenzel Jakob.
  
      This file is part of pbrt.
  
      Redistribution and use in source and binary forms, with or without
      modification, are permitted provided that the following conditions are
      met:
  
      - Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
  
      - Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
  
      THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
      IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
      TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
      PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
      HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
      DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
      THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
   */
  
  #if defined(_MSC_VER)
  #define NOMINMAX
  #pragma once
  #endif
  
  #ifndef PBRT_INTEGRATORS_DIRECTLIGHTING_H
  #define PBRT_INTEGRATORS_DIRECTLIGHTING_H
  
  // integrators/directlighting.h*
  #include "pbrt.h"
  #include "integrator.h"
  #include "scene.h"
  
  namespace pbrt {
  
  // LightStrategy Declarations
  enum class LightStrategy { UniformSampleAll, UniformSampleOne };
  
  // DirectLightingIntegrator Declarations
  class DirectLightingIntegrator : public SamplerIntegrator {
    public:
      // DirectLightingIntegrator Public Methods
      DirectLightingIntegrator(LightStrategy strategy, int maxDepth,
                               std::shared_ptr<Camera> camera,
                               std::shared_ptr<Sampler> sampler,
                               const Bounds2i &pixelBounds)
          : SamplerIntegrator(camera, sampler, pixelBounds),
            strategy(strategy),
            maxDepth(maxDepth) {}
      Spectrum Li(const RayDifferential &ray, const Scene &scene,
                  Sampler &sampler, MemoryArena &arena, int depth) const;
      void Preprocess(const Scene &scene, Sampler &sampler);
  
    private:
      // DirectLightingIntegrator Private Data
      const LightStrategy strategy;
      const int maxDepth;
      std::vector<int> nLightSamples;
  };
  
  DirectLightingIntegrator *CreateDirectLightingIntegrator(
      const ParamSet &params, std::shared_ptr<Sampler> sampler,
      std::shared_ptr<Camera> camera);
  
  }  // namespace pbrt
  
  #endif  // PBRT_INTEGRATORS_DIRECTLIGHTING_H
  