NeRF Raymarcher

Summary: An initial NeRF diff which sets up the folder structure and implements the raymarching algorithm of NeRF.

Reviewed By: nikhilaravi

Differential Revision: D25623990

fbshipit-source-id: ac6b05a9b866358bd4bbf44858f06859d8a6ebd1

projects/nerf/tests/__init__.py

@@ -0,0 +1 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All rights reserved.

projects/nerf/tests/test_raymarcher.py

@@ -0,0 +1,34 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All rights reserved.
+
+import unittest
+
+import torch
+from nerf.raymarcher import EmissionAbsorptionNeRFRaymarcher
+from pytorch3d.renderer import EmissionAbsorptionRaymarcher
+
+
+class TestRaymarcher(unittest.TestCase):
+    def setUp(self) -> None:
+        torch.manual_seed(42)
+
+    def test_raymarcher(self):
+        """
+        Checks that the nerf raymarcher outputs are identical to the
+        EmissionAbsorptionRaymarcher.
+        """
+
+        feat_dim = 3
+        rays_densities = torch.rand(100, 10, 1)
+        rays_features = torch.randn(100, 10, feat_dim)
+
+        out, out_nerf = [
+            raymarcher(rays_densities, rays_features)
+            for raymarcher in (
+                EmissionAbsorptionRaymarcher(),
+                EmissionAbsorptionNeRFRaymarcher(),
+            )
+        ]
+
+        self.assertTrue(
+            torch.allclose(out[..., :feat_dim], out_nerf[0][..., :feat_dim])
+        )