Make time slider effective in viewer (Fixes nerfstudio-project#2928)

Author: iSach

nerfstudio/viewer/render_state_machine.py

@@ -129,7 +129,10 @@ def _render_img(self, camera_state: CameraState):
 
         image_height, image_width = self._calculate_image_res(camera_state.aspect)
 
-        camera = get_camera(camera_state, image_height, image_width)
+        if self.viewer.include_time:
+            camera = get_camera(camera_state, image_height, image_width, self.viewer.control_panel.time)
+        else:
+            camera = get_camera(camera_state, image_height, image_width)
         camera = camera.to(self.viewer.get_model().device)
         assert isinstance(camera, Cameras)
         assert camera is not None, "render called before viewer connected"

nerfstudio/viewer/utils.py

@@ -42,7 +42,7 @@ class CameraState:
 
 
 def get_camera(
-    camera_state: CameraState, image_height: int, image_width: Optional[Union[int, float]] = None
+    camera_state: CameraState, image_height: int, image_width: Optional[Union[int, float]] = None, time: float = 0.0
 ) -> Cameras:
     """Returns the camera intrinsics matrix and the camera to world homogeneous matrix.
 
@@ -74,7 +74,7 @@ def get_camera(
         cy=pp_h,
         camera_type=camera_state.camera_type,
         camera_to_worlds=camera_state.c2w.to(torch.float32)[None, ...],
-        times=torch.tensor([0.0], dtype=torch.float32),
+        times=torch.tensor([time], dtype=torch.float32),
     )
     return camera