[BugFix] More resilient interactive_rendering.py

Author: matteobettini

vmas/interactive_rendering.py

@@ -101,18 +101,25 @@ def _cycle(self):
                 self.reset = False
                 total_rew = [0] * self.n_agents
 
-            action_list = [[0.0] * agent.action_size for agent in self.agents]
-            action_list[self.current_agent_index] = self.u[
-                : self.agents[self.current_agent_index].action_size
-            ]
+            if self.n_agents > 0:
+                action_list = [[0.0] * agent.action_size for agent in self.agents]
+                action_list[self.current_agent_index][
+                    : self.agents[self.current_agent_index].dynamics.needed_action_size
+                ] = self.u[
+                    : self.agents[self.current_agent_index].dynamics.needed_action_size
+                ]
+            else:
+                action_list = []
 
             if self.n_agents > 1 and self.control_two_agents:
-                action_list[self.current_agent_index2] = self.u2[
-                    : self.agents[self.current_agent_index2].action_size
+                action_list[self.current_agent_index2][
+                    : self.agents[self.current_agent_index2].dynamics.needed_action_size
+                ] = self.u2[
+                    : self.agents[self.current_agent_index2].dynamics.needed_action_size
                 ]
             obs, rew, done, info = self.env.step(action_list)
 
-            if self.display_info:
+            if self.display_info and self.n_agents > 0:
                 # TODO: Determine number of lines of obs_str and render accordingly
                 obs_str = str(InteractiveEnv.format_obs(obs[self.current_agent_index]))
                 message = f"\t\t{obs_str[len(obs_str) // 2:]}"