Using PyGame with PyOgre

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Using PyGame with PyOgre

Original version by Josh Taylor (deficite)

PyGame with PyOgre.....why?

PyOgre, like C++ OGRE, was not intended as a complete game SDK. Therefore one must find other API's to fill in the gaps (a game is more than just graphics). PyGame is a good choice for this because it provides close to everything PyOgre doesn't. Anything one can do with SDL can be accomplished using PyGame. Check it out at http://www.pygame.org

Getting PyOgre and PyGame to Meld

The process of getting PyOgre to render to a PyGame window is quite simple. The trick is simply to tell PyOgre not to create a window but instead use the window PyGame creates:

   def _createWindow(self, width, height, fullscreen):
       "Creates a PyGame window and sets PyOgre to render onto it"
       self.screen = pygame.display.set_mode((width,height))
       renderParameters = ogre._StringStringMap()
       renderParameters['externalWindowHandle'] = str(pygame.display.get_wm_info()['window'])
       self.renderWindow = self.root.createRenderWindow('PyOgre through PyGame', width, height, \
                                                        fullscreen, renderParameters)
       self.renderWindow.active = True

Complete code example and application class

I have provided an application class (which the above code was taken from) to base programs off of or to study:

# Written by: Josh Taylor (deficite) <joshtaylor.mail@gmail.com>
import pygame
from pygame.locals import *
from pyogre import ogre 

class PyGameOGREApp:
    "Provides a base for an application using PyGame and PyOgre"
    def __init__(self, width=640, height=480, fullscreen=False):
        self._initPyGame()
        self._initPyOgre()
        self._createWindow(width, height, fullscreen)
        self._createViewport()
        self._loadResources("resources.cfg")
        self._createEntities()
    def _initPyGame(self):
        "Starts up PyGame"
        pygame.init()
    def _initPyOgre(self):
        "Instantiates the PyOgre root and sceneManager objects and initialises"
        self.root = ogre.Root("plugins.cfg")
        self.root.showConfigDialog()
        self.root.initialise(False)
        self.sceneManager = self.root.getSceneManager(ogre.ST_GENERIC)
    def _createWindow(self, width, height, fullscreen):
        "Creates a PyGame window and sets PyOgre to render onto it"
        self.screen = pygame.display.set_mode((width,height))
        renderParameters = ogre._StringStringMap()
        renderParameters['externalWindowHandle'] = str(pygame.display.get_wm_info()['window'])
        self.renderWindow = self.root.createRenderWindow('PyOgre through PyGame', width, height, \
                                                         fullscreen, renderParameters)
        self.renderWindow.active = True
    def _createViewport(self):
        "Creates the user's viewport and camera"
        self.camera = self.sceneManager.createCamera("camera")
	self.camera.position = (0, 0, 500)
	self.camera.lookAt((0, 0, -300))
	self.camera.nearClipDistance = 5     
        self.viewport = self.renderWindow.addViewport(self.camera)
	self.viewport.backgroundColour = (0, 0, 0)
    def _loadResources(self, rcfile):
        "Loads the resource paths from specified resource config file"
        rc = ogre.ConfigFile()
        rc.loadFromFile(rcfile)
        for section, key, path in rc.values:
            ogre.ResourceGroupManager.getSingleton().addResourceLocation(path, key, section)
        ogre.ResourceGroupManager.getSingleton().initialiseAllResourceGroups()
    def _createEntities(self):
        "For simple demo purposes this can be used to create entities and attach them to sceneNode's"
        self.entities = [self.sceneManager.createEntity("robot", "robot.mesh")]
        self.sceneNodes = [self.sceneManager.rootSceneNode.createChildSceneNode("robotNode")]
        for i in range(len(self.sceneNodes)):
            self.sceneNodes[i].attachObject(self.entities[i])
    def _createScene(self):
        "Prepare the scene. All logic should go here"
        pass
    def _presentScene(self):
        "Render the scene and anything else needed done at the time of presentation"
        self.root.renderOneFrame()
    def run(self):
        "Brings the application to life"
        while self._processEvents():
            self._createScene()
            self._presentScene()
        pygame.quit()
    def _processEvents(self):
        "Process events and take appropriate action"
        for event in pygame.event.get():
            if event.type is QUIT:
                return False
            elif event.type is KEYDOWN and event.key is K_ESCAPE:
                return False
        return True

# Instantiate and run!
app = PyGameOGREApp()
app.run()

Press escape or the window manager's close button to exit the application.