Update docs, fix Pygame window, and improve camera stage timing

engine/display/backends/pygame.py

@@ -99,9 +99,6 @@ class PygameDisplay:
         self.width = width
         self.height = height
 
-        import os
-
-        os.environ["SDL_VIDEODRIVER"] = "dummy"
 
         try:
             import pygame

engine/pipeline/adapters/camera.py

@@ -1,5 +1,6 @@
 """Adapter for camera stage."""
 
+import time
 from typing import Any
 
 from engine.pipeline.core import DataType, PipelineContext, Stage
@@ -13,6 +14,7 @@ class CameraStage(Stage):
         self.name = name
         self.category = "camera"
         self.optional = True
+        self._last_frame_time: float | None = None
 
     @property
     def stage_type(self) -> str:
@@ -39,9 +41,17 @@ class CameraStage(Stage):
         if data is None:
             return data
 
-        # Apply camera offset to items
+        current_time = time.perf_counter()
+        dt = 0.0
+        if self._last_frame_time is not None:
+            dt = current_time - self._last_frame_time
+            self._camera.update(dt)
+        self._last_frame_time = current_time
+
+        ctx.set_state("camera_y", self._camera.y)
+        ctx.set_state("camera_x", self._camera.x)
+
         if hasattr(self._camera, "apply"):
-            # Extract viewport dimensions from context params
             viewport_width = ctx.params.viewport_width if ctx.params else 80
             viewport_height = ctx.params.viewport_height if ctx.params else 24
             return self._camera.apply(data, viewport_width, viewport_height)