Minor type fixes (#24)

nerfacc/utils.py

@@ -47,7 +47,7 @@ def volumetric_marching(
     render_step_size: float = 1e-3,
     near_plane: float = 0.0,
     stratified: bool = False,
-) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
+) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
     """Volumetric marching with occupancy test.
 
     Note: this function is not differentiable to inputs.

nerfacc/volumetric_rendering.py

@@ -69,10 +69,10 @@ def volumetric_rendering_pipeline(
     rays_d = rays_d.contiguous()
     scene_aabb = scene_aabb.contiguous()
     scene_occ_binary = scene_occ_binary.contiguous()
-    render_bkgd = render_bkgd.contiguous()
 
     with torch.no_grad():
         # Ray marching and occupancy check.
+        assert scene_resolution is not None
         packed_info, frustum_starts, frustum_ends = volumetric_marching(
             rays_o,
             rays_d,
@@ -126,6 +126,7 @@ def volumetric_rendering_pipeline(
     # )
 
     if render_bkgd is not None:
+        render_bkgd = render_bkgd.contiguous()
         colors = colors + render_bkgd * (1.0 - opacities)
 
     return colors, opacities, n_marching_samples, n_rendering_samples