CS 354R: Computer Game Technology

Transcription

1 CS 354R: Computer Game Technology Ogre Overview Fall 2017

2 Working with Ogre Ogre is a graphics engine not actually a game engine Things it has: Resource management Camera and animation support Input handling Rendering loop Things it doesn t have: Pre-existing game objects or object hierarchies Pre-existing game components Physics and simulation Networking support AI support 2

3 Resource Configurations resources.cfg contains directories of assets Scripts Meshes Textures GUI layouts Do not use environment variables Cannot search subdirectories 3

4 Resource and Scene Manager Resource Manager handles resource pool Index Look up Load Destroy Scene Manager handles scene geometry, objects and behaviors Spatial partitioning Culling Rendering 4

5 Initialize Configuration mroot = new Ogre::Root(mPluginsCfg); // Load resource paths from config file Ogre::ConfigFile cf; cf.load(mresourcescfg); // Parse all sections & settings in the file Ogre::ConfigFile::SectionIterator seci = cf.getsectioniterator(); Ogre::String secname, typename, archname; while (seci.hasmoreelements()) { secname = seci.peeknextkey(); Ogre::ConfigFile::SettingsMultiMap *settings = seci.getnext(); Ogre::ConfigFile::SettingsMultiMap::iterator i; for (i = settings->begin(); i!= settings->end(); ++i) { typename = i->first; archname = i->second; Ogre::ResourceGroupManager::getSingleton(). addresourcelocation(archname, typename, secname); // Show the configuration dialog and initialize the system if((mroot->restoreconfig() mroot->showconfigdialog())) { //If initialized, create a render window mwindow = mroot->initialise(true, Demo App"); else { return false; 5

6 Initialize Resource Mgr and Scene // Set default mipmap level (note: some APIs ignore this) Ogre::TextureManager::getSingleton().setDefaultNumMipmaps(5); // initialise all resource groups Ogre::ResourceGroupManager::getSingleton().initialiseAllResourceGroups(); // Create the SceneManager, in this case a generic one mscenemgr = mroot->createscenemanager("defaultscenemanager"); // Create a scene mscenemgr->setskybox(true, "Examples/MorningSkyBox", 5000, false); PlayingField* bcourt = new PlayingField(mSceneMgr); ball = new Ball(mSceneMgr); bcourt->addchild(ball->getnode()); ball->setplayingfield(bcourt); 6

7 What else do we need? 7

8 Camera Cameras have: Position LookAt Near plane Far plane Aspect ratio Cameras render out to a portion of the screen using a viewport (Silicon Graphics) 8

9 Setting up a Camera // Create the camera mcamera = mscenemgr->createcamera("playercam"); // Position it near front of the room mcamera->setposition(ogre::vector3(0.0f, 0.0f, 0.4f * bcourt->getlength())); // Look at the origin mcamera->lookat(ogre::vector3(0,0,0)); mcamera->setnearclipdistance(5); // create a default camera controller mcameraman = new OgreBites::SdkCameraMan(mCamera); // Create one viewport, entire window Ogre::Viewport* vp = mwindow->addviewport(mcamera); vp->setbackgroundcolour(ogre::colourvalue(0,0,0)); // Alter the camera aspect ratio to match the viewport mcamera->setaspectratio( Ogre::Real(vp->getActualWidth()) / Ogre::Real(vp->getActualHeight())); 9

10 Camera vs Camera Manager Cameras are tools for looking into the scene Provide mathematical information to OpenGL for drawing the scene Camera managers are tools for controlling camera position and orientation Handle mouse and keyboard input to camera Usually allow for first-person and orbital camera movements SdkCameraMan is part of the OgreBites sample framework Not natively available on the lab machines Other open source frameworks available Also possible to create your own! 10

11 Mouse and Keyboard Listeners OIS (Object-Oriented Input System) handles mouse and keyboard events Listener for each mouse, keyboard, joystick etc Listeners are protected functions Listeners take events as parameters One listener per device for performance reasons 11

12 Mouse and Keyboard Input #include <OISEvents.h> #include <OISInputManager.h> #include <OISKeyboard.h> #include <OISMouse.h> #include <OgreRenderWindow.h> #include <SdkTrays.h> #include <SdkCameraMan.h> class ControlListener : public OIS::KeyListener, public OIS::MouseListener { protected: OIS::InputManager* inputmanager; OIS::Mouse* mouse; OIS::Keyboard* keyboard; Ogre::RenderWindow* window; Ogre::Camera* camera; bool mshutdown; 12

13 Mouse and Keyboard Input cont d protected: // OIS::KeyListener virtual bool keypressed( const OIS::KeyEvent &arg ); virtual bool keyreleased( const OIS::KeyEvent &arg ); // OIS::MouseListener virtual bool mousemoved( const OIS::MouseEvent &arg ); virtual bool mousepressed( const OIS::MouseEvent &arg, OIS::MouseButtonID id ); virtual bool mousereleased( const OIS::MouseEvent &arg, OIS::MouseButtonID id ); public: BaseApplication(Ogre::RenderWindow* window); ~BaseApplication(); ; 13

14 Using Callbacks Events associated with a listener Buffer of events dispatched as callbacks Allow the programmer to react to changes in the system 14

15 Buffered Input Callbacks bool BaseApplication::keyPressed( const OIS::KeyEvent &arg ) { if (arg.key == OIS::KC_ESCAPE) { mshutdown = true; return true; bool BaseApplication::keyReleased(const OIS::KeyEvent &arg) { return true; bool BaseApplication::mouseMoved(const OIS::MouseEvent &arg) { return true; bool BaseApplication::mousePressed(const OIS::MouseEvent &arg, OIS::MouseButtonID id) { return true; bool BaseApplication::mouseReleased(const OIS::MouseEvent &arg, OIS::MouseButtonID id) { return true; 15

16 Using Callbacks What if other frameworks need to know about events? Example: Camera manager should change camera position based on mouse or keyboard input Needs a method that can take events from one framework and use it in its own framework Controller/GUI manager uses inject calls to take device input from callback and pass it back to controller/ GUI manager 16

17 Buffered Input Callbacks bool ControlListener::keyReleased( const OIS::KeyEvent &arg ) { cameramanager->injectkeyup(arg); return true; bool ControlListener::mouseMoved( const OIS::MouseEvent &arg ) { cameramanager->injectmousemove(arg); return true; bool ControlListener::mousePressed( const OIS::MouseEvent &arg, OIS::MouseButtonID id ) { cameramanager->injectmousedown(arg, id); return true; bool ControlListener::mouseReleased( const OIS::MouseEvent &arg, OIS::MouseButtonID id ) { cameramanager->injectmouseup(arg, id); return true; 17

18 Game Objects #include <Ogre.h> #include "PlayingField.h class Ball { protected: Ogre::SceneNode* rootnode; Ogre::Real bradius; Ogre::Vector3 bdirection; Ogre::Real bspeed; PlayingField* grounds; public: Ball(Ogre::SceneManager* scnmgr); ~Ball(); void move(const Ogre::FrameEvent& evt); Ogre::SceneNode* getnode() { return rootnode; void setplayingfield(playingfield * pf) { grounds = pf; ; 18

19 A Game Object #include <OgreEntity.h> #include <OgreSceneManager.h> #include "Ball.h Ball::Ball(Ogre::SceneManager* scnmgr) { Ogre::Entity* ball = scnmgr->createentity("sphere", "sphere.mesh"); ball->setmaterialname("ballcolor/cubemap"); ball->setcastshadows(true); rootnode = scnmgr->createscenenode("ball"); rootnode->attachobject(ball); rootnode->scale(0.1f,0.1f,0.1f); bradius = 10.0f; bdirection = Ogre::Vector3(1.0f, 2.0f, 3.0f); bdirection.normalise(); bspeed = 250.0f; void Ball::move(const Ogre::FrameEvent& evt) { Ogre::Vector3 bposition = rootnode->getposition(); if (bposition.y < -grounds->getheight()/2.0f + bradius && bdirection.y < 0.0f) bdirection.y = -bdirection.y; if (bposition.y > grounds->getheight()/2.0f - bradius && bdirection.y > 0.0f) bdirection.y = -bdirection.y; if (bposition.z < -grounds->getlength()/2.0f + bradius && bdirection.z < 0.0f) bdirection.z = -bdirection.z; if (bposition.z > grounds->getlength()/2.0f - bradius && bdirection.z > 0.0f) bdirection.z = -bdirection.z; if (bposition.x < -grounds->getwidth()/2.0f + bradius && bdirection.x < 0.0f) bdirection.x = -bdirection.x; if (bposition.x > grounds->getwidth()/2.0f - bradius && bdirection.x > 0.0f) bdirection.x = -bdirection.x; rootnode->translate(bspeed * evt.timesincelastframe * bdirection); 19

20 What s Missing? 20

21 Frame Listener Listener associated with frame events framestarted framerenderingqueued frameended Frame callbacks return true until rendering terminates Possible to register multiple FrameListeners framerenderingqueued called after rendering has been queued for GPU Good use of CPU cycles for changes in next frame 21

22 Rendering Loop class MyFrameListener : public Ogre::FrameListener { // Rendering loop mroot->startrendering(); bool MyFrameListener::frameRenderingQueued(const Ogre::FrameEvent& evt) { if(mwindow->isclosed()) return false; mcontrols->update(); if (mcontrols->exit()) return false; mgui->framerenderingqueued(evt); if (!mgui->isdialogvisible()) { // if dialog isn't up, then update the scene mcameraman->framerenderingqueued(evt); // Move the ball ball->move(evt); return true; 22

23 Unregistering OIS Should unregister OIS when the game program finishes How can we do this? WindowEventListener callbacks windowresized callback tracks window (screen) size windowclosed callback tracks window closing destroy OIS objects for window that created objects 23

24 Window Event Listener //Unattach OIS before window shutdown (very important under Linux) void MyWindowListener::windowClosed(Ogre::RenderWindow* rw) { //Only close for window that created OIS (the main window in these demos) if (rw == mwindow) { if (minputmanager) { minputmanager->destroyinputobject(mmouse); minputmanager->destroyinputobject(mkeyboard); OIS::InputManager::destroyInputSystem(mInputManager); minputmanager = 0; 24