"""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, WIDTH, HEIGHT
+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, viewport=(0, 0)):
- screen.clear()
+ 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 - viewport[0],
- y * TILE_SIZE - viewport[1])
+ pos = (x * TILE_SIZE, y * TILE_SIZE)
if 'image' not in tile:
# Skip broken tiles for now
continue
- if 0 <= pos[0] < WIDTH:
- if 0 <= pos[1] < HEIGHT:
- screen.blit(tile['image'], pos)
+ self._surface.blit(tile['image'], pos)
+
+ def draw(self, screen, viewport):
+ screen.clear()
+ # 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: