最簡單的Ogre系列之一——Ogre框架程序（不使用ExampleListener/Application）

原文：http://blog.csdn.net/zhuxiaoyang2000/article/details/6324080

本文參考Ogre官網上的MinimalApplication寫了一個最簡單的Ogre程序，不包含任何資源文件，當然了，也沒有任何功能: )。本文寫作的初衷是：

（1）ExampleListener/Application包含的內容過於豐富，不便於在此基礎上寫出簡單的程序應用，如2D程序。它需要的資源文件和相應的配置文件對於簡單的程序顯得臃腫。

（2）現有的MinimalApplication混淆了Listener和Application，而且將所有文件寫到了一個程序裏面，文檔結構不清晰。

（3）更重要的是通過自己寫這樣一個程序，能夠了解Ogre建立的詳細過程，有助於理解Ogre的框架。

閒言少敘，進入正題。建立一個Win32程序，程序包括三個文件，分別是SimpleListener.h，SimpleApplication.h和main.cpp。該程序使用的是Ogre 1.6.5版本，1.7.x版本可能需要修改相應的include文件。

程序需要包含庫OgreMain_d.lib、OIS_d.lib（Debug模式），或OgreMain.lib、OIS.lib（Release模式）；需要包含dll文件OgreMain_d.dll、OIS_d.dll、RenderSystem_Direct3D9_d.dll（Debug模式），或OgreMain.dll、OIS.dll、RenderSystem_Direct3D9.dll（Release模式）。

程序需要建立一個空文件resources.cfg。

程序需要建立一個文件Plugins.cfg，其內容爲

# Defines plugins to load
# Define plugin folder
PluginFolder=.
# Define plugins
Plugin=RenderSystem_Direct3D9_d

下面是SimpleListener.h的內容。

/*
  ======================================================================
   SimpleListener.h --- protoype to show off the simple ogre listener.
  ----------------------------------------------------------------------
   Author : Zhu Xiaoyang ([email protected])
   Creation Date : Apr 14 2011
   Description:
   This is a mini Ogre Listener, including SimpleFrameListener,
   SimpleKeyListener and SimpleMouseListener.
  =======================================================================
*/
#ifndef __SimpleListener_H__
#define __SimpleListener_H__
#include "Ogre.h"
#include "OgreFrameListener.h"
#include <OIS/OIS.h>
using namespace Ogre;
/**
----------------------------------------------------------------------
    class SimpleFrameListener
----------------------------------------------------------------------
*/
class SimpleFrameListener : public FrameListener
{
public:
    SimpleFrameListener(OIS::Keyboard* keyboard, OIS::Mouse* mouse)
    {
        mKeyboard = keyboard;
        mMouse    = mouse;
    }
    //This gets called before the next frame is being rendered.
    bool frameStarted(const FrameEvent& evt)
    {
        //update the input devices
        mKeyboard->capture();
        mMouse->capture();
        //exit if key KC_ESCAPE pressed
        if( mKeyboard->isKeyDown( OIS::KC_ESCAPE ) )
            return false;
        else
            return true;
    }
    //This gets called at the end of a frame
    bool frameEnded(const FrameEvent& evt)
    {
        return true;
    }
private:
    OIS::Keyboard* mKeyboard;
    OIS::Mouse*    mMouse;
};
/**
----------------------------------------------------------------------
    class SimpleKeyListener
----------------------------------------------------------------------
*/
class SimpleKeyListener : public OIS::KeyListener
{
public:
    bool keyPressed    (const OIS::KeyEvent& e)   { return true; }
    bool keyReleased   (const OIS::KeyEvent& e)   { return true; }
};
/**
----------------------------------------------------------------------
    class SimpleMouseListener
----------------------------------------------------------------------
*/
class SimpleMouseListener : public OIS::MouseListener
{
public:
    bool mouseMoved    (const OIS::MouseEvent& e) { return true; }
    bool mousePressed  (const OIS::MouseEvent& e, OIS::MouseButtonID id) { return true; }
    bool mouseReleased (const OIS::MouseEvent& e, OIS::MouseButtonID id) { return true; }
};
#endif //__SimpleListener_H__

下面是SimpleApplication.h的內容。

/*
  ==========================================================================
   SimpleApplication.h --- protoype to show off the simple ogre application.
  --------------------------------------------------------------------------
   Author : Zhu Xiaoyang ([email protected])
   Creation Date : Apr 14 2011
   Description:
   This is a mini Ogre Application.  It does noting.
  ==========================================================================
*/
#ifndef __SimpleApplication_H__
#define __SimpleApplication_H__
#include "Ogre.h"
#include "SimpleListener.h"
using namespace Ogre;
/**
----------------------------------------------------------------------
    class SimpleApplication
----------------------------------------------------------------------
*/
class SimpleApplication
{
public:
    SimpleApplication()
    {
        mRoot = 0;
    }
    ~SimpleApplication()
    {
        if(mRoot)
            OGRE_DELETE mRoot;
    }
    //start example
    void go()
    {
        if( !setup() )
            return;
        /**
        ----------------------------------------------------------------------
        8 start rendering
        @ blocks until a frame listener returns false.
          eg. from pressing escape in this example.
        ----------------------------------------------------------------------
        */
        mRoot->startRendering();
        /**
        ----------------------------------------------------------------------
        9 clean up
        ----------------------------------------------------------------------
        */
        destroyScene();
    }
    //setup Ogre
    bool setup()
    {
        /**
        ----------------------------------------------------------------------
        1 Enter ogre
        ----------------------------------------------------------------------
        */
        mRoot = new Root;
        /**
        ----------------------------------------------------------------------
        2 Configure resource paths
        @ Load resource paths from config file
          File format is:
          [ResourceGroupName]
          ArchiveType=Path
          .. repeat
          For example:
          [General]
          FileSystem=media/
          zip=packages/level1.zip
        ----------------------------------------------------------------------
        */
        ConfigFile cf;
        cf.load("resources.cfg");
        //Go through all sections & settings in the file
        ConfigFile::SectionIterator seci = cf.getSectionIterator();
        String secName, typeName, archName;
        while ( seci.hasMoreElements() )
        {
            secName = seci.peekNextKey();
            ConfigFile::SettingsMultiMap  *settings = seci.getNext();
            ConfigFile::SettingsMultiMap::iterator i;
            for (i = settings->begin(); i != settings->end(); ++i)
            {
                typeName = i->first;
                archName = i->second;
                ResourceGroupManager::getSingleton().addResourceLocation(
                    archName, typeName, secName);
            }
        }
        /**
        ----------------------------------------------------------------------
        3 Configures the application and creates the window
        ----------------------------------------------------------------------
        */
        if ( !mRoot->showConfigDialog() )
        {
            //Ogre
            delete mRoot;
            return false; //Exit the application on cancel
        }
        mWindow = mRoot->initialise(true, "Simple Ogre App");
        ResourceGroupManager::getSingleton().initialiseAllResourceGroups();
        /**
        ----------------------------------------------------------------------
        4 Create the SceneManager
        @ SceneManager Type
          ST_GENERIC = octree
          ST_EXTERIOR_CLOSE = simple terrain
          ST_EXTERIOR_FAR = nature terrain (depreciated)
          ST_EXTERIOR_REAL_FAR = paging landscape
          ST_INTERIOR = Quake3 BSP
        ----------------------------------------------------------------------
        */
        mSceneMgr = mRoot->createSceneManager(ST_GENERIC);
        /**
        ----------------------------------------------------------------------
        5 Create the camera
        ----------------------------------------------------------------------
        */
        mCamera = mSceneMgr->createCamera("SimpleCamera");
        /**
        ----------------------------------------------------------------------
        6 Create one viewport, entire window
        ----------------------------------------------------------------------
        */
        Viewport* viewport = mWindow->addViewport(mCamera);
        /**
        ----------------------------------------------------------------------
        7 Add OIS input handling
        ----------------------------------------------------------------------
        */
        OIS::ParamList pl;
        size_t windowHnd = 0;
        std::ostringstream windowHndStr;
        //tell OIS about the Ogre window
        mWindow->getCustomAttribute("WINDOW", &windowHnd);
        windowHndStr<<windowHnd;
        pl.insert( std::make_pair( std::string("WINDOW"), windowHndStr.str() ) );
        //setup the manager, keyboard and mouse to handle input
        inputManager = OIS::InputManager::createInputSystem( pl );
        keyboard = static_cast<OIS::Keyboard*>(inputManager->createInputObject( OIS::OISKeyboard, true ) );
        mouse    = static_cast<OIS::Mouse*>(inputManager->createInputObject( OIS::OISMouse,    true ) );
        //tell OIS about the window's dimensions
        unsigned int width, height, depth;
        int top, left;
        mWindow->getMetrics(width, height, depth, left, top);
        const OIS::MouseState &ms = mouse->getMouseState();
        ms.width  = width;
        ms.height = height;
        //everything is set up, now we listen for input and frames (replaces while loops)
        //key events
        keyListener = new SimpleKeyListener();
        keyboard->setEventCallback(keyListener);
        //mouse events
        mouseListener = new SimpleMouseListener();
        mouse->setEventCallback(mouseListener);
        //render events
        mFrameListener = new SimpleFrameListener(keyboard, mouse);
        mRoot->addFrameListener(mFrameListener);
        return true;
    }
    //clean Ogre
    void destroyScene()
    {
        //OIS
        inputManager->destroyInputObject(mouse);             mouse = 0;
        inputManager->destroyInputObject(keyboard);          keyboard = 0;
        OIS::InputManager::destroyInputSystem(inputManager); inputManager = 0;
        //listeners
        delete mFrameListener;
        delete mouseListener;
        delete keyListener;
    }
private:
    Root* mRoot;
    Camera* mCamera;
    SceneManager* mSceneMgr;
    RenderWindow* mWindow;
    //OIS
    OIS::InputManager* inputManager;
    OIS::Keyboard* keyboard;
    OIS::Mouse* mouse;
    //Listener
    SimpleKeyListener* keyListener;
    SimpleMouseListener* mouseListener;
    SimpleFrameListener* mFrameListener;
};
#endif //__SimpleApplication_H__

 

下面是main.cpp的內容。

 

#include "SimpleApplication.h"
#if OGRE_PLATFORM == OGRE_PLATFORM_WIN32
#define WIN32_LEAN_AND_MEAN
#include "windows.h"
#endif
#ifdef __cplusplus
extern "C" {
#endif
#if OGRE_PLATFORM == OGRE_PLATFORM_WIN32
INT WINAPI WinMain( HINSTANCE hInst, HINSTANCE, LPSTR strCmdLine, INT )
#else
int main(int argc, char **argv)
#endif
{
    // Create application object
    SimpleApplication app;
    srand(time(0));
    try {
        app.go();
    } catch( Exception& e ) {
#if OGRE_PLATFORM == OGRE_PLATFORM_WIN32
        MessageBoxA( NULL, e.getFullDescription().c_str(), "An exception has occured!", MB_OK | MB_ICONERROR | MB_TASKMODAL);
#else
        std::cerr << "An exception has occured: " << e.getFullDescription();
#endif
    }
    return 0;
}
#ifdef __cplusplus
}
#endif