          true, // Front to back.
          0, // Mip mode.
          true, // Local illumination.
+         true, // Opacity correction.
          false, // Jittering.
-         true, // Clip sphere.
-         true // Clip plane.
+         false, // Clip sphere.
+         false // Clip plane.
         ><<<gridSize, blockSize>>>(d_output, width, height,
-                                   500.0f / (float)numSlices,
+                                   diagonalVoxels / (float)numSlices,
                                    volSize * 0.5f,
                                    L, H,
                                    center, radius * radius,

  return make_float4(tmp.x, tmp.y, tmp.z, classification.w);
}

template<bool frontToBack, int mipMode, bool lighting, bool jittering, bool clipSphere, bool clipPlane>
__global__ void render(uint *d_output, const uint width, const uint height, const float dist,
                       const float3 volSizeHalf, const float3 L, const float3 H,
                       const float3 sphereCenter, const float sphereRadius,

                                           vd->vox[1] * vd->vox[1] +
                                           vd->vox[2] * vd->vox[2]));
  int numSlices = max(1, static_cast<int>(_renderState._quality * diagonalVoxels));

  // Inverse modelview-projection matrix.
  vvMatrix mvp, pr;
