Refined asteroid finding. Implemented a result display function.

gamemodel.py

@@ -2,20 +2,26 @@ import gameio
 import cv2
 import numpy as np
 
+def squared_distance(vec1, vec2):
+    """returns distance-squared between two x, y point tuples"""
+    return (vec1[0] - vec2[0])**2 + (vec1[1] - vec2[1])**2
+
 class GameModel:
     """Platform-independent representation of the game's state."""
     def __init__(self, io:gameio.AbstractGameIO):
         self.gameio = io
-        self.asteroids = [cv2.imread("images/game_assets/rock-big.png", 0),
-                          cv2.imread("images/game_assets/rock-normal.png", 0),
-                          cv2.imread("images/game_assets/rock-small.png", 0)
+        self.asteroids = [
+            ("big", cv2.imread("images/game_assets/rock-big.png", 0)),
+            ("normal", cv2.imread("images/game_assets/rock-normal.png", 0)),
+            ("small", cv2.imread("images/game_assets/rock-small.png", 0))
             ]
         self.frame = None
-        self.thresh = 0.6 # reconfigurable at runtime
+        self.cv_template_thresh = 0.6 # reconfigurable at runtime
+        self.duplicate_dist_thresh = 10
 
     def with_frame(fn):
         """Decorator to process screenshot to cv2 format once upon first requirement, then reuse."""
-        def inner(self):
+        def inner(self, *args, **kwargs):
             if self.frame is None:
                 print("Fetching frame.")
                 sshot = self.gameio.fetch_sshot()
@@ -23,7 +29,7 @@ class GameModel:
                 # Convert RGB to BGR 
                 self.frame = open_cv_image[:, :, ::-1].copy()
                 self.frame = cv2.cvtColor(self.frame, cv2.COLOR_BGR2GRAY)
-            return fn(self)
+            return fn(self, *args, **kwargs)
         return inner
 
     def clear_frame(self):
@@ -32,16 +38,27 @@ class GameModel:
     @with_frame
     def find_asteroids(self):
         asteroid_rects = []
-        displayable = np.copy(self.frame)
-        for a in self.asteroids:
+        for label, a in self.asteroids:
             h, w = a.shape
             res = cv2.matchTemplate(self.frame, a, cv2.TM_CCOEFF_NORMED)
-            loc = np.where( res >= self.thresh)
-            ## Example code for displaying detected asteroid locations
-            #for pt in zip(*loc[::-1]):
-            #    cv2.rectangle(displayable, pt, (pt[0] + w, pt[1] + h), 255, 1)
-        #cv2.imshow("Found asteroids", displayable)
-        #cv2.waitKey(0)
+            loc = np.where( res >= self.cv_template_thresh)
+            for pt in zip(*loc[::-1]):
+                if not asteroid_rects or squared_distance(asteroid_rects[-1][0], pt) > self.duplicate_dist_thresh:
+                    asteroid_rects.append((pt, (pt[0] + w, pt[1] + h), label))
+        return asteroid_rects
+
+    @with_frame
+    def display_results(self, results):
+        """Draws results on the current frame for test purposes."""
+        displayable = np.copy(self.frame)
+        for pt, wh, label in results:
+            cv2.rectangle(displayable, pt, wh, 255, 1)
+            cv2.putText(displayable, label, pt,
+                    cv2.FONT_HERSHEY_PLAIN,
+                    1.0, 255)
+        cv2.imshow("Results", displayable)
+        cv2.waitKey(0)
+
 
 if __name__ == '__main__':
     import platform
@@ -53,8 +70,18 @@ if __name__ == '__main__':
     else:
         io = gameio.LinuxGameIO()
 
-    input("Press <enter> to locate the game at the start screen.")
+    #input("Press <enter> to locate the game at the start screen.")
     gm = GameModel(io)
 
-    input("Press <enter> to detect asteroids on screen.")
-    gm.find_asteroids()
+    # for testing purposes, populating window location at top-left of my screen
+    # io.loc is None when the title screen isn't found.
+    # manually setting io.loc crops all screenshots as if the title was found.
+    import pyscreeze
+    io.loc = pyscreeze.Box(0, 25, 800, 599)
+
+    #input("Press <enter> to detect asteroids on screen.")
+    results = gm.find_asteroids()
+    print(f"Found {len(results)} asteroids")
+    for a in results:
+        print(a[0]) # position tuple
+    gm.display_results(results)