Recreate test level with underlay

[koperkapel.git] / koperkapel / scenes / level.py

diff --git a/koperkapel/scenes/level.py b/koperkapel/scenes/level.py
index a58c51d450ee3d8b04200e138b0687f3fef60f30..5c86629078551df0d69459b20d61b77b08093ffa 100644 (file)
--- a/koperkapel/scenes/level.py
+++ b/koperkapel/scenes/level.py
@@ -1,27 +1,42 @@
 """Render a level"""
 
 from pgzero.constants import keys
+from pygame import Surface
 from ..loaders.levelloader import levels
 from .base import Scene, ChangeSceneEvent
-from .constants import TILE_SIZE
+from ..constants import TILE_SIZE
 
 
 class LevelScene(Scene):
     """ Level scene. """
 
-    def __init__(self, level_name):
-        self._level_data = levels.load(level_name)
+    def enter(self, world):
+        self._level_data = levels.load(world.level.name)
         self._tiles = self._level_data['tiles']
+        self._surface = None
+        self._render()
 
-    def draw(self, screen):
+    def _render(self):
+        # We cache the rendered surface to avoid doing a large number
+        # of blits each frame, as that introduces a large performance
+        # overhead.
+        self._surface = Surface((len(self._tiles[0]) * TILE_SIZE,
+                                 len(self._tiles) * TILE_SIZE))
+        for y, row in enumerate(self._tiles):
+            for x, tile in enumerate(row):
+                pos = (x * TILE_SIZE, y * TILE_SIZE)
+                if 'image' not in tile:
+                    # Skip broken tiles for now
+                    continue
+                self._surface.blit(tile['image'], pos)
+
+    def draw(self, screen, viewport):
         screen.clear()
-        for tile in self._tiles:
-            pos = tile['pos']
-            pos = [pos[0] * TILE_SIZE, pos[1] * TILE_SIZE]
-            if 'image' not in tile:
-                # Skip broken tiles for now
-                continue
-            screen.blit(tile['image'], pos)
+        # Viewport is the position of the screen relative to the
+        # surface. We need the position of the surface relative to
+        # the screen for the blit, so this conversion
+        screen_pos = -viewport[0], -viewport[1]
+        screen.blit(self._surface, screen_pos)
 
     def on_key_down(self, key, mod, unicode):
         if key == keys.ESCAPE: