From: Neil <neil@dip.sun.ac.za>
Date: Tue, 16 Apr 2013 16:08:08 +0000 (+0200)
Subject: "better" auto-scrolling support
X-Git-Url: https://git.ctpug.org.za/?p=erdslangetjie.git;a=commitdiff_plain;h=5d0c2b6e0cc1e42281dc93919b3c04657b621313

"better" auto-scrolling support
---

diff --git a/erdslangetjie/__main__.py b/erdslangetjie/__main__.py
index 6ab5b18..148236b 100644
--- a/erdslangetjie/__main__.py
+++ b/erdslangetjie/__main__.py
@@ -30,9 +30,12 @@ class GameWindow(RelativeLayout):
         cols, rows = self.level_obj.get_size()
 
         super(GameWindow, self).__init__(
-                size=(cols*TILE_SIZE, rows*TILE_SIZE),
+                size=(cols * TILE_SIZE, rows * TILE_SIZE),
                 size_hint=(None, None))
 
+        self.x_scroll_margin = float(TILE_SIZE) / self.view.size[0]
+        self.y_scroll_margin = float(TILE_SIZE) / self.view.size[1]
+
         self.mouse_move = False
 
         self.player = ThePlayer()
@@ -68,9 +71,6 @@ class GameWindow(RelativeLayout):
                 bx += TILE_SIZE
             by += TILE_SIZE
 
-        self.draw_player()
-        self.draw_nemesis()
-
     def draw_player(self):
         if self.player_tile:
             self.remove_widget(self.player_tile)
@@ -83,34 +83,58 @@ class GameWindow(RelativeLayout):
             Rectangle(pos=sprite_pos, size=self.player_tile.size,
                     texture=self.player.get_texture())
         self.add_widget(self.player_tile)
-        # Player position in viewpoint coordinates
-        check_point = (sprite_pos[0] + TILE_SIZE / 2,
-                sprite_pos[1] + TILE_SIZE / 2)
-        true_point = self.to_parent(*check_point)
-        if not self.included(true_point):
-            # Scroll ourselves
-            while true_point[0] >= self.view.size[0] - TILE_SIZE:
-                self.pos = (self.pos[0] - 1.5 * TILE_SIZE, self.pos[1])
-                true_point = self.to_parent(*check_point)
-            while true_point[0] < TILE_SIZE:
-                self.pos = (self.pos[0] + 1.5 * TILE_SIZE, self.pos[1])
-                true_point = self.to_parent(*check_point)
-            while true_point[1] >= self.view.size[1] - TILE_SIZE:
-                self.pos = (self.pos[0], self.pos[1] - 1.5 * TILE_SIZE)
-                true_point = self.to_parent(*check_point)
-            while true_point[1] < TILE_SIZE:
-                self.pos = (self.pos[0], self.pos[1] + 1.5 * TILE_SIZE)
-                true_point = self.to_parent(*check_point)
-
-    def included(self, point):
-        if point[0] < TILE_SIZE:
+        for offset in [(TILE_SIZE - 1, TILE_SIZE - 1),
+                (-TILE_SIZE + 1, TILE_SIZE - 1),
+                (TILE_SIZE - 1, -TILE_SIZE + 1),
+                (-TILE_SIZE + 1, -TILE_SIZE + 1),
+                (0, 2 * TILE_SIZE - 2),
+                (-2 * TILE_SIZE + 2, 0),
+                (2 * TILE_SIZE - 2, 0),
+                (0, -2 * TILE_SIZE + 2),
+                (0, 0)]:
+            # Aim is to ensure a 'neighbourhood' around the player
+            # is visible if possible
+            check_point = (sprite_pos[0] + offset[0] + TILE_SIZE / 2,
+                    sprite_pos[1] + offset[1] + TILE_SIZE / 2)
+            true_point = self.to_parent(*check_point)
+            if check_point[0] < 0:
+                continue
+            if check_point[1] < 0:
+                continue
+            if check_point[0] >= self.size[0]:
+                continue
+            if check_point[1] >= self.size[1]:
+                continue
+            while not self.included(true_point, 0):
+                # Scroll ourselves
+                if true_point[0] >= self.view.size[0]:
+                    self.view.scroll_x += self.x_scroll_margin
+                    true_point = self.to_parent(*check_point)
+                    #print '-x', self.view.scroll_x, self.view.scroll_y
+                elif true_point[0] < 0:
+                    self.view.scroll_x -= self.x_scroll_margin
+                    true_point = self.to_parent(*check_point)
+                    #print '+x', self.view.scroll_x, self.view.scroll_y
+                elif true_point[1] >= self.view.size[1]:
+                    self.view.scroll_y += self.y_scroll_margin
+                    true_point = self.to_parent(*check_point)
+                    #print '+y', self.view.scroll_x, self.view.scroll_y
+                elif true_point[1] < 0:
+                    self.view.scroll_y -= self.y_scroll_margin
+                    true_point = self.to_parent(*check_point)
+                    #print '-y', self.view.scroll_x, self.view.scroll_y
+                #print true_point, self.view.size
+
+    def included(self, point, margin):
+        if point[0] < margin:
             return False
-        if point[0] >= self.view.pos[0] - TILE_SIZE:
+        if point[0] >= self.view.size[0] - margin:
             return False
-        if point[1] < TILE_SIZE:
+        if point[1] < margin:
             return False
-        if point[1] >= self.view.pos[1] - TILE_SIZE:
+        if point[1] >= self.view.size[1] - margin:
             return False
+        return True
 
     def draw_nemesis(self):
         if not self.nemesis.on_board():
@@ -155,12 +179,17 @@ class GameWindow(RelativeLayout):
         if self.level_obj.at_exit(self.player.pos):
             # Jump to next level
             self.level_obj = self.level_list.advance_to_next_level()
+            self.remove_widget(self.nemesis_tile)
             self.nemesis.reset_pos()
             if self.level_obj:
                 self.level_obj.load_tiles()
                 self.player.pos = self.level_obj.enter_pos
                 self.remove_widget(self.player_tile)
+                self.view.scroll_x = 0
+                self.view.scroll_y = 0
                 self.build()
+                self.draw_nemesis()
+                self.draw_player()
             else:
                 print 'You won!'
                 sys.exit(1)
@@ -205,7 +234,10 @@ class GameApp(App):
         game.build()
         root.add_widget(game)
         # Ensure the player is visible
+        root.scroll_x = 0
+        root.scroll_y = 0
         game.draw_player()
+        game.draw_nemesis()
         return root