Fix #501.

Summary: Gradient calculation flags were not properly routed through the Python interface. This diff fixes this. In particular, gradients for focal length (only if no other camera gradients were calculated) and opacity were not calculated as required.

Reviewed By: gkioxari

Differential Revision: D25921202

fbshipit-source-id: 22cbae3bda886d81bb95878f0be45c2ddd29934c

pytorch3d/renderer/points/pulsar/renderer.py

@@ -238,8 +238,9 @@ class _Render(torch.autograd.Function):
                 ctx.needs_input_grad[3]
                 or ctx.needs_input_grad[4]
                 or ctx.needs_input_grad[5]
-                or ctx.needs_input_grad[6],
-                ctx.needs_input_grad[13],
+                or ctx.needs_input_grad[6]
+                or ctx.needs_input_grad[7],
+                ctx.needs_input_grad[14],
                 None,  # No debug information provided.
             )
         else: