message: Reimplement gpu_buffer_rt w/o thrust
diff: // See the LICENSE file for details.
  #include <cuda_runtime.h>
  -#include <thrust/fill.h>
  -#include <thrust/execution_policy.h>
  +#include "../cuda/fill.h"
  #include "../cpu_buffer_rt.h"
  namespace visionaray
  @@ -52,7 +51,7 @@ void gpu_buffer_rt<ColorFormat, DepthFormat>::clear_color_buffer(vec4 const& c)
  c
  );
  - thrust::fill(thrust::device, color(), color() + width() * height(), cc);
  + cuda::fill(color(), width() * height() * sizeof(color_type), &cc, sizeof(color_type));
  }
  template <pixel_format ColorFormat, pixel_format DepthFormat>
  @@ -67,7 +66,7 @@ void gpu_buffer_rt<ColorFormat, DepthFormat>::clear_depth_buffer(float d)
  d
  );
  - thrust::fill(thrust::device, depth(), depth() + width() * height(), dd);
  + cuda::fill(depth(), width() * height() * sizeof(depth_type), &dd, sizeof(depth_type));
  }
  template <pixel_format ColorFormat, pixel_format DepthFormat>
  