Merge pull request cztomczak#410 from neilmunday/master

cztomczak · web-flow · commit 5c91c656747e · 2018-02-23T07:44:59.000+01:00
Added frame rate limiting code to PySDL2 example for issue cztomczak#324
diff --git a/examples/pysdl2.py b/examples/pysdl2.py
@@ -5,10 +5,17 @@
 further down. Pull requests for the missing functionality are welcome.
 
 Requires PySDL2 and SDL2 libraries.
- 
+
+Usage:
+
+    python pysdl2.py [-v] [-h]
+
+    -v  turn on debug messages
+    -h  display help info
+
 Tested configurations:
 - Windows 7: SDL 2.0.7 and PySDL2 0.9.6
-- Fedora 25: SDL2 2.0.5 with PySDL2 0.9.3
+- Fedora 26: SDL2 2.0.7 with PySDL2 0.9.6
 - Ubuntu 14.04: SDL2 with PySDL2 0.9.6
 
 Install instructions:
@@ -19,7 +26,7 @@
    - Ubuntu: sudo apt-get install libsdl2-dev
 2. Install PySDL2 using pip package manager:
    pip install PySDL2
- 
+
 Missing functionality:
 - Performance is still not perfect, see Issue #324 for further details
 - Keyboard modifiers that are not yet handled in this example:
@@ -36,33 +43,65 @@
   https://github.com/neilmunday/pes/blob/master/lib/pes/ui.py
 """
 
+import argparse
+import logging
 import sys
+
+
+def die(msg):
+    """
+    Helper function to exit application on failed imports etc.
+    """
+    sys.stderr.write("%s\n" % msg)
+    sys.exit(1)
+
+
 try:
     # noinspection PyUnresolvedReferences
     from cefpython3 import cefpython as cef
 except ImportError:
-    print("ERROR: cefpython3 package not found")
-    print("To install type: `pip install cefpython3`")
-    sys.exit(1)
+    die("""ERROR: cefpython3 package not found\n
+    To install type: `pip install cefpython3`""")
 try:
     # noinspection PyUnresolvedReferences
     import sdl2
     # noinspection PyUnresolvedReferences
     import sdl2.ext
 except ImportError:
-    print("ERROR: SDL2 package not found")
-    print("To install type: `pip install PySDL2`")
-    sys.exit(1)
+    die("ERROR: SDL2 package not found\nTo install type: `pip install PySDL2`")
 try:
     # noinspection PyUnresolvedReferences
     from PIL import Image
 except ImportError:
-    print("ERROR: PIL package not found")
-    print("To install type: pip install Pillow")
-    sys.exit(1)
+    die("ERROR: PIL package not found\nTo install type: pip install Pillow")
 
 
 def main():
+    parser = argparse.ArgumentParser(
+        description='PySDL2 / cefpython example',
+        add_help=True
+    )
+    parser.add_argument(
+        '-v',
+        '--verbose',
+        help='Turn on debug info',
+        dest='verbose',
+        action='store_true'
+    )
+    args = parser.parse_args()
+    logLevel = logging.INFO
+    if args.verbose:
+        logLevel = logging.DEBUG
+    logging.basicConfig(
+        format='[%(filename)s %(levelname)s]: %(message)s',
+        level=logLevel
+    )
+    logging.info("Using PySDL2 %s" % sdl2.__version__)
+    version = sdl2.SDL_version()
+    sdl2.SDL_GetVersion(version)
+    logging.info(
+        "Using SDL2 %s.%s.%s" % (version.major, version.minor, version.patch)
+    )
     # The following variables control the dimensions of the window
     # and browser display area
     width = 800
@@ -74,6 +113,8 @@ def main():
     browserWidth = width
     # Mouse wheel fudge to enhance scrolling
     scrollEnhance = 40
+    # desired frame rate
+    frameRate = 100
     # Initialise CEF for offscreen rendering
     sys.excepthook = cef.ExceptHook
     switches = {
@@ -86,16 +127,18 @@ def main():
     }
     browser_settings = {
         # Tweaking OSR performance (Issue #240)
-        "windowless_frame_rate": 100
+        "windowless_frame_rate": frameRate
     }
     cef.Initialize(settings={"windowless_rendering_enabled": True},
                    switches=switches)
+    logging.debug("cef initialised")
     window_info = cef.WindowInfo()
     window_info.SetAsOffscreen(0)
     # Initialise SDL2 for video (add other init constants if you
     # require other SDL2 functionality e.g. mixer,
     # TTF, joystick etc.
     sdl2.SDL_Init(sdl2.SDL_INIT_VIDEO)
+    logging.debug("SDL2 initialised")
     # Create the window
     window = sdl2.video.SDL_CreateWindow(
         'cefpython3 SDL2 Demo',
@@ -124,7 +167,17 @@ def main():
     browser.WasResized()
     # Begin the main rendering loop
     running = True
+    # FPS debug variables
+    frames = 0
+    logging.debug("beginning rendering loop")
+    resetFpsTime = True
+    fpsTime = 0
     while running:
+        # record when we started drawing this frame
+        startTime = sdl2.timer.SDL_GetTicks()
+        if resetFpsTime:
+            fpsTime = sdl2.timer.SDL_GetTicks()
+            resetFpsTime = False
         # Convert SDL2 events into CEF events (where appropriate)
         events = sdl2.ext.get_events()
         for event in events:
@@ -269,6 +322,17 @@ def main():
             sdl2.SDL_Rect(0, headerHeight, browserWidth, browserHeight)
         )
         sdl2.SDL_RenderPresent(renderer)
+        # FPS debug code
+        frames += 1
+        if sdl2.timer.SDL_GetTicks() - fpsTime > 1000:
+            logging.debug("FPS: %d" % frames)
+            frames = 0
+            resetFpsTime = True
+        # regulate frame rate
+        if sdl2.timer.SDL_GetTicks() - startTime < 1000.0 / frameRate:
+            sdl2.timer.SDL_Delay(
+                (1000 / frameRate) - (sdl2.timer.SDL_GetTicks() - startTime)
+            )
     # User exited
     exit_app()
 
@@ -289,31 +353,33 @@ def get_key_code(key):
     if key in key_map:
         return key_map[key]
     # Key not mapped, raise exception
-    print("[pysdl2.py] Keyboard mapping incomplete:"
-          " unsupported SDL key %d."
-          " See https://wiki.libsdl.org/SDLKeycodeLookup for mapping."
-          % key)
+    logging.error(
+        """
+        Keyboard mapping incomplete: unsupported SDL key %d.
+        See https://wiki.libsdl.org/SDLKeycodeLookup for mapping.
+        """ % key
+    )
     return None
 
 
 class LoadHandler(object):
     """Simple handler for loading URLs."""
-    
+
     def OnLoadingStateChange(self, is_loading, **_):
         if not is_loading:
-            print("[pysdl2.py] Page loading complete")
-            
+            logging.info("Page loading complete")
+
     def OnLoadError(self, frame, failed_url, **_):
         if not frame.IsMain():
             return
-        print("[pysdl2.py] Failed to load %s" % failed_url)
+        logging.error("Failed to load %s" % failed_url)
 
 
 class RenderHandler(object):
     """
     Handler for rendering web pages to the
     screen via SDL2.
-    
+
     The object's texture property is exposed
     to allow the main rendering loop to access
     the SDL2 texture.
@@ -324,11 +390,11 @@ def __init__(self, renderer, width, height):
         self.__height = height
         self.__renderer = renderer
         self.texture = None
-            
+
     def GetViewRect(self, rect_out, **_):
         rect_out.extend([0, 0, self.__width, self.__height])
         return True
-    
+
     def OnPaint(self, element_type, paint_buffer, **_):
         """
         Using the pixel data from CEF's offscreen rendering
@@ -378,9 +444,9 @@ def OnPaint(self, element_type, paint_buffer, **_):
                 depth = 32
                 pitch = self.__width * 4
             else:
-                print("[pysdl2.py] ERROR: Unsupported mode: %s" % mode)
+                logging.error("ERROR: Unsupported mode: %s" % mode)
                 exit_app()
-            
+
             pxbuf = image.tobytes()
             # Create surface
             surface = sdl2.SDL_CreateRGBSurfaceFrom(
@@ -403,14 +469,14 @@ def OnPaint(self, element_type, paint_buffer, **_):
             # Free the surface
             sdl2.SDL_FreeSurface(surface)
         else:
-            print("[pysdl2.py] WARNING: Unsupport element_type in OnPaint")
+            logging.warning("Unsupport element_type in OnPaint")
 
 
 def exit_app():
     """Tidy up SDL2 and CEF before exiting."""
     sdl2.SDL_Quit()
     cef.Shutdown()
-    print("[pysdl2.py] Exited gracefully")
+    logging.info("Exited gracefully")
 
 
 if __name__ == "__main__":
