Fix mask_to_channels with trilinear renderer (#382)

Author: eigenvivek

diffdrr/renderers.py

@@ -240,7 +240,7 @@ def forward(
             B, D, _ = img.shape
             C = int(mask.max().item() + 1)
             channels = _get_voxel(
-                mask, xyzs, img=None, mode=self.mode, align_corners=align_corners
+                mask, xyzs, img=None, mode="nearest", align_corners=align_corners
             ).long()
             img = (
                 torch.zeros(B, C, D)

notebooks/api/01_renderers.ipynb

@@ -376,7 +376,7 @@
     "            B, D, _ = img.shape\n",
     "            C = int(mask.max().item() + 1)\n",
     "            channels = _get_voxel(\n",
-    "                mask, xyzs, img=None, mode=self.mode, align_corners=align_corners\n",
+    "                mask, xyzs, img=None, mode=\"nearest\", align_corners=align_corners\n",
     "            ).long()\n",
     "            img = (\n",
     "                torch.zeros(B, C, D)\n",