Camera 2D hotfix 2 (#2200)

* Correct `Camera2D.angle`  getter and adding unit test

* added rotation to the camera gui example

* linting pass

Author: DragonMoffon

arcade/camera/camera_2d.py

@@ -741,7 +741,7 @@ def angle(self) -> float:
         clock-wise.
         """
         # Note that this is flipped as we want 0 degrees to be vert. Normally you have y first and then x.
-        return degrees(atan2(self._camera_data.position[0], self._camera_data.position[1]))
+        return degrees(atan2(self._camera_data.up[0], self._camera_data.up[1]))
 
     @angle.setter
     def angle(self, value: float) -> None:
@@ -752,7 +752,7 @@ def angle(self, value: float) -> None:
         """
         _r = radians(value)
         # Note that this is flipped as we want 0 degrees to be vert.
-        self._camera_data.up = (-sin(_r), cos(_r), 0.0)
+        self._camera_data.up = (sin(_r), cos(_r), 0.0)
 
     @property
     def zoom(self) -> float:

arcade/gui/examples/gui_and_camera.py

@@ -154,6 +154,8 @@ def upgrade_spawn_rate(event: UIOnClickEvent):
         )
         self.timer.with_background(color=arcade.color.TRANSPARENT_BLACK)
 
+        self.cam_pos = self.ui.camera.position
+
     def on_draw_before_ui(self):
         self.ingame_camera.use()  # use the in-game camera to draw in-game objects
         self.sprites.draw()
@@ -230,7 +232,10 @@ def on_update(self, delta_time: float) -> Optional[bool]:
 
         # slide in the UI from bottom, until total time reaches 2 seconds
         progress = min(1.0, self._total_time / 2)
-        self.ui.camera.bottom_left = (0, 50 * (1 - progress))
+
+        # Because we allow for camera rotation we have work on the center
+        # and not the edge because it behaves oddly otherwise
+        self.ui.camera.position = (self.window.center_x, 50 * (1 - progress) + self.window.center_y)
 
         return False
 
@@ -241,6 +246,9 @@ def on_key_press(self, symbol: int, modifiers: int) -> Optional[bool]:
             arcade.close_window()
         if symbol == arcade.key.ENTER:
             self.window.show_view(MyCoinGame())
+        if symbol == arcade.key.SPACE:
+            # Allows user to rotate camera to show off full functionality of the ui camera
+            self.ui.camera.angle += 5
 
         return False
 

tests/unit/camera/test_camera2d.py

@@ -2,6 +2,8 @@
 
 import pytest as pytest
 
+from pyglet.math import Vec2
+
 from arcade import Window, LRBT
 from arcade.camera import Camera2D
 from arcade.camera.data_types import ZeroProjectionDimension, OrthographicProjectionData
@@ -136,3 +138,17 @@ def test_move_camera_and_unproject(window: Window):
     screen_coordinate = camera.project(world_coordinate)
 
     assert screen_coordinate == (pytest.approx(0), pytest.approx(0))
+
+def test_rotate_camera_with_angle(window: Window):
+    camera = Camera2D()
+    camera.angle = 45
+    assert camera.angle == pytest.approx(45.0)
+    assert camera.up == pytest.approx(Vec2(0.5**0.5, 0.5**0.5))
+
+    camera.angle = 180
+    assert camera.angle == pytest.approx(180.0)
+    assert camera.up == pytest.approx(Vec2(0.0, -1.0))
+
+    camera.angle = 270
+    assert camera.angle == pytest.approx(-90.0)
+    assert camera.up == pytest.approx(Vec2(-1.0, 0.0))