Major Bug fix (Scales and camera)

Removed unnecessary scaling factors in calculations. To achieve the same visual scale, I changed the default star_img_scale to 5000 ,img_scale to 100000 and distance scale to 100.

Bug fix: the position of new object when camera pos != (0,0)  used to be wrong due to the aforementioned scaling factors. The problem is now fixed.

gravity_sim/__main__.py

@@ -61,16 +61,18 @@ def _check_events(self):
                         if event.button == 3:  # right click
                             self.stats.start_holding_rclick()
                             self.new_obj_mouse_pos = mouse_pos
+                            self.new_obj_camera_pos_x = self.camera.pos_x
+                            self.new_obj_camera_pos_y = self.camera.pos_y
                     elif self.menu.menu_active == True:
                         if event.button == 1:  # left click
                             self.menu.check_button(self, mouse_pos)
                 case pygame.MOUSEBUTTONUP:
                     if self.stats.is_holding_rclick == True:
                         if event.button == 3:
                             self.stats.end_holding_rclick()
-                            Grav_obj.create_star(self, self.new_obj_mouse_pos)
+                            Grav_obj.create_star(self, self.new_obj_mouse_pos, self.new_obj_camera_pos_x, self.new_obj_camera_pos_y)
                 case pygame.MOUSEWHEEL:
-                    self.settings.distance_scale += 0.1 * event.y
+                    self.settings.distance_scale += 10 * event.y
                 case pygame.QUIT:
                     sys.exit()
 
@@ -142,7 +144,7 @@ def _read_command_line_arg(self):
             "--img_scale",
             "-i",
             nargs=2,
-            default=[20, 400],
+            default=[5000, 100000],
             type=float,
             help="Usage: --img_scale <solar image scale>, <obj image scale>",
         )
@@ -163,14 +165,12 @@ def _new_obj_draw_line_circle(self):
         R = Grav_obj.SOLAR_RADIUS * (m ** (1.0 / 3.0))
         img_R = (
             R
-            * 0.25
+            * (699.0 / 894.0)   # Sun size in the img with size (894 x 894)
             * self.settings.star_img_scale
-            * self.settings.screen_height
-            * 699.0
-            / 894.0
         )
+        new_obj_circle_pos = [self.new_obj_mouse_pos[0] + self.new_obj_camera_pos_x - self.camera.pos_x, self.new_obj_mouse_pos[1] + self.new_obj_camera_pos_y - self.camera.pos_y]
         pygame.draw.circle(
-            self.screen, "orange", self.new_obj_mouse_pos, img_R, width=1
+            self.screen, "orange", new_obj_circle_pos, img_R, width=1
         )
 
 

gravity_sim/grav_obj.py

@@ -29,16 +29,12 @@ def __init__(
         if name == "Sun":
             self.img_diameter = (
                 self.diameter
-                * 0.25
                 * self.settings.star_img_scale
-                * self.settings.screen_height
             )
         else:
             self.img_diameter = (
                 self.diameter
-                * 0.25
                 * self.settings.img_scale
-                * self.settings.screen_height
             )
 
         # Note: apparent_scale = real_scale * img_scale
@@ -64,21 +60,17 @@ def update(self):
         """Update the apparent position of all grav_objs with camera"""
         self.rect.center = (
             self.params["r1"]
-            * 0.25
             * self.settings.distance_scale
-            * self.settings.screen_height
             + self.screen_rect.centerx
             - self.camera.pos_x,
             -self.params["r2"]
-            * 0.25
             * self.settings.distance_scale
-            * self.settings.screen_height
             + self.screen_rect.centery
             - self.camera.pos_y,
         )
 
     @classmethod
-    def create_star(self, grav_sim, mouse_pos):
+    def create_star(self, grav_sim, mouse_pos, camera_pos_x, camera_pos_y):
         main_dir_path = os.path.dirname(__file__)
         path_sun = os.path.join(main_dir_path, "images/sun.png")
         m = 1 * 0.5 * grav_sim.stats.holding_rclick_time
@@ -89,23 +81,15 @@ def create_star(self, grav_sim, mouse_pos):
                 "r1": (
                     mouse_pos[0]
                     - grav_sim.screen.get_rect().centerx
-                    - grav_sim.camera.pos_x
+                    + camera_pos_x
                 )
-                / (
-                    grav_sim.settings.distance_scale
-                    * 0.25
-                    * grav_sim.settings.screen_height
-                ),
+                / grav_sim.settings.distance_scale,
                 "r2": -(
                     mouse_pos[1]
                     - grav_sim.screen.get_rect().centery
-                    - grav_sim.camera.pos_y
+                    + camera_pos_y
                 )
-                / (
-                    grav_sim.settings.distance_scale
-                    * 0.25
-                    * grav_sim.settings.screen_height
-                ),
+                / grav_sim.settings.distance_scale,
                 "r3": 0.0,
                 "v1": 0.0,
                 "v2": 0.0,

gravity_sim/settings.py

@@ -7,8 +7,8 @@ def __init__(
         screen_height,
         star_img_scale,
         img_scale,
-        time_speed: int = 1000,
-        dt: float = 0.01,
+        time_speed: int = 1,
+        dt: float = 0.1,
     ):
         # To change the default settings of screen_width, screen_height, star_img_scale, img_scale, go to _read_command_line_arg function in __main__.py
         self.screen_width = screen_width
@@ -19,7 +19,7 @@ def __init__(
         self.grav_obj_color = (255, 255, 255)
         self.star_img_scale = star_img_scale
         self.img_scale = img_scale
-        self.distance_scale = 1
+        self.distance_scale = 100
         self.time_speed = time_speed
         self.dt = dt
 
@@ -68,8 +68,8 @@ def screen_height(self, value):
     # Img may corrupt if the scale is too large.
     @star_img_scale.setter
     def star_img_scale(self, value):
-        if value > 100:
-            self._star_img_scale = 100
+        if value > 500000:
+            self._star_img_scale = 500000
         elif value < 0:
             self._star_img_scale = 0
         else:
@@ -78,8 +78,8 @@ def star_img_scale(self, value):
     # Img may corrupt if the scale is too large.
     @img_scale.setter
     def img_scale(self, value):
-        if value > 1000:
-            self._img_scale = 1000
+        if value > 5000000:
+            self._img_scale = 5000000
         elif value < 0:
             self._img_scale = 0
         else:
@@ -89,8 +89,8 @@ def img_scale(self, value):
     def distance_scale(self, value):
         if value > 1000:
             self._distance_scale = 1000
-        elif value <= 0.1:
-            self._distance_scale = 0.1
+        elif value <= 0:
+            self._distance_scale = 0
         else:
             self._distance_scale = value