[Render] Introduce scenario.render_origin (#93)

* amend

* amend

* amend

* amend

Author: matteobettini

vmas/simulator/environment/environment.py

@@ -19,7 +19,6 @@
     DEVICE_TYPING,
     override,
     TorchUtils,
-    VIEWER_MIN_ZOOM,
     X,
     Y,
 )
@@ -666,7 +665,9 @@ def render(
 
             self._init_rendering()
 
-        zoom = max(VIEWER_MIN_ZOOM, self.scenario.viewer_zoom)
+        if self.scenario.viewer_zoom <= 0:
+            raise ValueError("Scenario viewer zoom must be > 0")
+        zoom = self.scenario.viewer_zoom
 
         if aspect_ratio < 1:
             cam_range = torch.tensor([zoom, zoom / aspect_ratio], device=self.device)
@@ -685,8 +686,12 @@ def render(
             viewer_size_fit = (
                 torch.stack(
                     [
-                        torch.max(torch.abs(all_poses[:, X])),
-                        torch.max(torch.abs(all_poses[:, Y])),
+                        torch.max(
+                            torch.abs(all_poses[:, X] - self.scenario.render_origin[X])
+                        ),
+                        torch.max(
+                            torch.abs(all_poses[:, Y] - self.scenario.render_origin[Y])
+                        ),
                     ]
                 )
                 + 2 * max_agent_radius
@@ -698,10 +703,10 @@ def render(
             )
             cam_range *= torch.max(viewer_size)
             self.viewer.set_bounds(
-                -cam_range[X],
-                cam_range[X],
-                -cam_range[Y],
-                cam_range[Y],
+                -cam_range[X] + self.scenario.render_origin[X],
+                cam_range[X] + self.scenario.render_origin[X],
+                -cam_range[Y] + self.scenario.render_origin[Y],
+                cam_range[Y] + self.scenario.render_origin[Y],
             )
         else:
             # update bounds to center around agent

vmas/simulator/scenario.py

@@ -14,7 +14,7 @@
     AGENT_OBS_TYPE,
     AGENT_REWARD_TYPE,
     INITIAL_VIEWER_SIZE,
-    VIEWER_MIN_ZOOM,
+    VIEWER_DEFAULT_ZOOM,
 )
 
 if typing.TYPE_CHECKING:
@@ -46,8 +46,10 @@ def __init__(self):
         self._world = None
         self.viewer_size = INITIAL_VIEWER_SIZE
         """The size of the rendering viewer window. This can be changed in the :class:`~make_world` function. """
-        self.viewer_zoom = VIEWER_MIN_ZOOM
-        """The zoom of the rendering camera. This can be changed in the :class:`~make_world` function. """
+        self.viewer_zoom = VIEWER_DEFAULT_ZOOM
+        """The zoom of the rendering camera (a lower value means more zoom). This can be changed in the :class:`~make_world` function. """
+        self.render_origin = (0.0, 0.0)
+        """The origin of the rendering camera when ``agent_index_to_focus`` is None in the ``render()`` arguments. This can be changed in the :class:`~make_world` function. """
         self.plot_grid = False
         """Whether to plot a grid in the scenario rendering background. This can be changed in the :class:`~make_world` function. """
         self.grid_spacing = 0.1

vmas/simulator/utils.py

@@ -20,7 +20,7 @@
 Y = 1
 Z = 2
 ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-VIEWER_MIN_ZOOM = 1.2
+VIEWER_DEFAULT_ZOOM = 1.2
 INITIAL_VIEWER_SIZE = (700, 700)
 LINE_MIN_DIST = 4 / 6e2
 COLLISION_FORCE = 100