Added clear_scene() to Grid class. Tests required (once grid_updating optimised).

micah-huth · micah-huth · commit 57c38540d76a · 2020-06-22T11:10:23.000+10:00
diff --git a/graphics/graphics_grid.py b/graphics/graphics_grid.py
@@ -21,13 +21,13 @@ def draw_grid(self):
         num_squares = 10  # Length of the grid in each direction (in units)
         relative_cam = True  # Whether the grid follows the camera rotation and movement
 
-        the_grid = self.create_grid(relative_cam, num_squares)
+        the_grid = self.__create_grid(relative_cam, num_squares)
         self.grid_object[0] = the_grid
 
         # Update the labels instead of recreating them
         create_grid_numbers(self.grid_object[1], relative_cam, num_squares)
 
-    def create_grid(self, bool_camera_relative, num_squares):
+    def __create_grid(self, bool_camera_relative, num_squares):
         """
         Draw a grid along each 3D plane, that is closest to the camera.
 
@@ -171,6 +171,30 @@ def set_visibility(self, is_visible):
         # TODO this will need to be uncommented once grid_object reuse is done
         #for number in self.grid_object[1]:
         #    number.visible = is_visible
+        
+    def clear_scene(self):
+        """
+        Clear the canvas of all objects (keeping the grid)
+
+        Due to how VPython operates, there is no 'deletion' of objects directly.
+        To 'delete' objects, first they must be rendered invisible.
+
+        Then: if a new object with the same variable name is used, the previous memory will be freed.
+        Or: del variable_name will free its memory.
+        If the object wasn't invisible, it would remain visible in the scene.
+
+        Since the scene doesnt track variable names, the best way to clear the scene is to render all objects invisible,
+        and have the user assume they are all deleted. However, all objects can be redisplayed by setting the visibility
+        """
+        # Save current grid visibility
+        grid_visibility = self.grid_object[0].visible
+
+        # Set all objects invisible
+        for scene_object in scene.objects:
+            scene_object.visible = False
+
+        # Set grid visibility to previous
+        self.set_visibility(grid_visibility)
 
 
 def create_line(pos1, pos2):
diff --git a/tests/graphics_test_features.py b/tests/graphics_test_features.py
@@ -2,7 +2,7 @@
 These functions are not ordinary testing functions.
 These tests cannot be automated, and must be manually validated.
 
-To execute, import all from this file into the console. "from graphics.graphics_test_features import *"
+To execute, import all from this file into the console. "from tests.graphics_test_features import *"
 Next select which test you which to run, and call the function.
 A canvas will be created and display the respective graphics.
 Verify the output is as expected.
@@ -139,6 +139,15 @@ def test_puma560_angle_change():
     puma560.print_joint_angles(True)
 
 
+def test_clear_scene():
+    the_grid = init_canvas()
+    puma560 = import_puma_560()
+    puma560.move_base(vector(1, 1, 0))
+    sleep(2)
+    the_grid.clear_scene()
+    del puma560
+
+
 def test_animate_joints():
     pass
 
