message: Reimplement pixel_unpack_buffer_rt w/o thrust
diff: #include <cassert>
  #include <stdexcept>
  -#include <thrust/fill.h>
  -#include <thrust/execution_policy.h>
  -
  +#include "../cuda/fill.h"
  #include "color_conversion.h"
  @@ -68,7 +66,7 @@ void pixel_unpack_buffer_rt<ColorFormat, DepthFormat>::clear_color_buffer(vec4 c
  begin_frame();
  - thrust::fill(thrust::device, color(), color() + width() * height(), cc);
  + cuda::fill(color(), width() * height() * sizeof(color_type), &cc, sizeof(color_type));
  end_frame();
  }
  @@ -89,7 +87,7 @@ void pixel_unpack_buffer_rt<ColorFormat, DepthFormat>::clear_depth_buffer(float
  begin_frame();
  - thrust::fill(thrust::device, depth(), depth() + width() * height(), dd);
  + cuda::fill(depth(), width() * height() * sizeof(depth_type), &dd, sizeof(depth_type));
  end_frame();
  }
  