Function makeLocalVolume

modules/mpi/tutorials/ospMPIDistribTutorialVolume.cpp:174–237

}

VolumeBrick makeLocalVolume(const int mpiRank, const int mpiWorldSize)
{
  const vec3i grid = computeGrid(mpiWorldSize);
  const vec3i brickId(mpiRank % grid.x,
      (mpiRank / grid.x) % grid.y,
      mpiRank / (grid.x * grid.y));
  // The bricks are 64^3 + 1 layer of ghost voxels on each axis
  const vec3i brickVolumeDims = vec3i(32);
  const vec3i brickGhostDims = vec3i(brickVolumeDims + 2);

  // The grid is over the [0, grid * brickVolumeDims] box
  worldBounds = box3f(vec3f(0.f), vec3f(grid * brickVolumeDims));
  const vec3f brickLower = brickId * brickVolumeDims;
  const vec3f brickUpper = brickId * brickVolumeDims + brickVolumeDims;

  VolumeBrick brick;
  brick.bounds = box3f(brickLower, brickUpper);
  // we just put ghost voxels on all sides here, but a real application
  // would change which faces of each brick have ghost voxels dependent
  // on the actual data
  brick.ghostBounds = box3f(brickLower - vec3f(1.f), brickUpper + vec3f(1.f));

  brick.brick = cpp::Volume("structuredRegular");

  brick.brick.setParam("dimensions", brickGhostDims);

  // we use the grid origin to place this brick in the right position inside
  // the global volume
  brick.brick.setParam("gridOrigin", brick.ghostBounds.lower);

  // generate the volume data to just be filled with this rank's id
  const size_t nVoxels = brickGhostDims.x * brickGhostDims.y * brickGhostDims.z;
  std::vector<uint8_t> volumeData(nVoxels, static_cast<uint8_t>(mpiRank));
  brick.brick.setParam("data",
      cpp::CopiedData(static_cast<const uint8_t *>(volumeData.data()),
          vec3ul(brickVolumeDims)));

  brick.brick.commit();

  brick.model = cpp::VolumetricModel(brick.brick);
  cpp::TransferFunction tfn("piecewiseLinear");
  std::vector<vec3f> colors = {vec3f(0.f, 0.f, 1.f), vec3f(1.f, 0.f, 0.f)};
  std::vector<float> opacities = {0.05f, 1.f};

  tfn.setParam("color", cpp::CopiedData(colors));
  tfn.setParam("opacity", cpp::CopiedData(opacities));
  // color the bricks by their rank, we pad the range out a bit to keep
  // any brick from being completely transparent
  range1f valueRange = range1f(0, mpiWorldSize);
  tfn.setParam("value", valueRange);
  tfn.commit();
  brick.model.setParam("transferFunction", tfn);
  brick.model.setParam("samplingRate", 0.5f);
  brick.model.commit();

  brick.group = cpp::Group();
  brick.group.setParam("volume", cpp::CopiedData(brick.model));
  brick.group.commit();