OGRE之输入系统笔记

OGRE之输入系统笔记

     一个基本的例子：
    

#include "ExampleApplication.h"

class TutorialFrameListener : public ExampleFrameListener, public OIS::MouseListener, public OIS::KeyListener
{
public:
    TutorialFrameListener(RenderWindow* win, Camera* cam, SceneManager *sceneMgr)
        : ExampleFrameListener(win, cam, true, true)
    {
        // Populate the camera and scene manager containers
        mCamNode = cam->getParentSceneNode();
        mSceneMgr = sceneMgr;

        // set the rotation and move speed
        mRotate = 0.13;
        mMove = 250;

        // continue rendering
        mContinue = true;

        mMouse->setEventCallback(this);
        mKeyboard->setEventCallback(this);

        mDirection = Vector3::ZERO;
    }

    bool frameStarted(const FrameEvent &evt)
    {
        if(mMouse)
            mMouse->capture();
        if(mKeyboard) 
            mKeyboard->capture();

        mCamNode->translate(mDirection * evt.timeSinceLastFrame, Node::TS_LOCAL);
        return mContinue;
    }

    // MouseListener
    bool mouseMoved(const OIS::MouseEvent &e)
    {
        if (e.state.buttonDown(OIS::MB_Right))
        {
            mCamNode->yaw(Degree(-mRotate * e.state.X.rel), Node::TS_WORLD);
            mCamNode->pitch(Degree(-mRotate * e.state.Y.rel), Node::TS_LOCAL);
        }
        return true;
    }

    bool mousePressed(const OIS::MouseEvent &e, OIS::MouseButtonID id)
    {
        Light *light = mSceneMgr->getLight("Light1");
        switch (id)
        {
        case OIS::MB_Left:
            light->setVisible(! light->isVisible());
            break;
        }
        return true;
    }

    bool mouseReleased(const OIS::MouseEvent &e, OIS::MouseButtonID id) { return true; }

    // KeyListener
    bool keyPressed(const OIS::KeyEvent &e)
    {
        switch (e.key)
        {
        case OIS::KC_ESCAPE: 
            mContinue = false;
            break;

        case OIS::KC_1:
            mCamera->getParentSceneNode()->detachObject(mCamera);
            mCamNode = mSceneMgr->getSceneNode("CamNode1");
            mCamNode->attachObject(mCamera);
            break;

        case OIS::KC_2:
            mCamera->getParentSceneNode()->detachObject(mCamera);
            mCamNode = mSceneMgr->getSceneNode("CamNode2");
            mCamNode->attachObject(mCamera);
            break;

        case OIS::KC_UP:
        case OIS::KC_W:
            mDirection.z -= mMove;
            break;

        case OIS::KC_DOWN:
        case OIS::KC_S:
            mDirection.z += mMove;
            break;

        case OIS::KC_LEFT:
        case OIS::KC_A:
            mDirection.x -= mMove;
            break;

        case OIS::KC_RIGHT:
        case OIS::KC_D:
            mDirection.x += mMove;
            break;

        case OIS::KC_PGDOWN:
        case OIS::KC_E:
            mDirection.y -= mMove;
            break;

        case OIS::KC_PGUP:
        case OIS::KC_Q:
            mDirection.y += mMove;
            break;
        }
        return true;
    }

    bool keyReleased(const OIS::KeyEvent &e)
    {
        switch (e.key)
        {
        case OIS::KC_UP:
        case OIS::KC_W:
            mDirection.z += mMove;
            break;

        case OIS::KC_DOWN:
        case OIS::KC_S:
            mDirection.z -= mMove;
            break;

        case OIS::KC_LEFT:
        case OIS::KC_A:
            mDirection.x += mMove;
            break;

        case OIS::KC_RIGHT:
        case OIS::KC_D:
            mDirection.x -= mMove;
            break;

        case OIS::KC_PGDOWN:
        case OIS::KC_E:
            mDirection.y += mMove;
            break;

        case OIS::KC_PGUP:
        case OIS::KC_Q:
            mDirection.y -= mMove;
            break;
        } // switch
        return true;
    }
protected:
    Real mRotate;          // The rotate constant
    Real mMove;            // The movement constant

    SceneManager *mSceneMgr;   // The current SceneManager
    SceneNode *mCamNode;   // The SceneNode the camera is currently attached to

    bool mContinue;        // Whether to continue rendering or not
    Vector3 mDirection;     // Value to move in the correct direction
};

class TutorialApplication : public ExampleApplication
{
public:
    void createCamera(void)
    {
        // create camera, but leave at default position
        mCamera = mSceneMgr->createCamera("PlayerCam"); 
        mCamera->setNearClipDistance(5);
    }

    void createScene(void)
    {
        mSceneMgr->setAmbientLight(ColourValue(0.25, 0.25, 0.25));

        // add the ninja
        Entity *ent = mSceneMgr->createEntity("Ninja", "ninja.mesh");
        SceneNode *node = mSceneMgr->getRootSceneNode()->createChildSceneNode("NinjaNode");
        node->attachObject(ent);

        // create the light
        Light *light = mSceneMgr->createLight("Light1");
        light->setType(Light::LT_POINT);
        light->setPosition(Vector3(250, 150, 250));
        light->setDiffuseColour(ColourValue::White);
        light->setSpecularColour(ColourValue::White);

        // Create the scene node
        node = mSceneMgr->getRootSceneNode()->createChildSceneNode("CamNode1", Vector3(-400, 200, 400));
        node->yaw(Degree(-45));
        node->attachObject(mCamera);

        // create the second camera node/pitch node
        node = mSceneMgr->getRootSceneNode()->createChildSceneNode("CamNode2", Vector3(0, 200, 400));
    }

    void createFrameListener(void)
    {
        // Create the FrameListener
        mFrameListener = new TutorialFrameListener(mWindow, mCamera, mSceneMgr);
        mRoot->addFrameListener(mFrameListener);

        // Show the frame stats overlay
        mFrameListener->showDebugOverlay(true);
    }
};

#if OGRE_PLATFORM == PLATFORM_WIN32 || OGRE_PLATFORM == OGRE_PLATFORM_WIN32
#define WIN32_LEAN_AND_MEAN
#include "windows.h"

INT WINAPI WinMain(HINSTANCE hInst, HINSTANCE, LPSTR strCmdLine, INT)
#else
int main(int argc, char **argv)
#endif
{
    // Create application object
    TutorialApplication app;

    try {
        app.go();
    } catch(Exception& e) {
#if OGRE_PLATFORM == PLATFORM_WIN32 || OGRE_PLATFORM == OGRE_PLATFORM_WIN32
        MessageBox(NULL, e.getFullDescription().c_str(), "An exception has occurred!", MB_OK | MB_ICONERROR | MB_TASKMODAL);
#else
        fprintf(stderr, "An exception has occurred: %s\n",
            e.getFullDescription().c_str());
#endif
    }

    return 0;
}

按照理论来说
unbuffered：不断的响应按键信息，直到按键放开。例如，按下上下左右，使得角色持续移动。 
               一般来讲适合于3D场景漫游过程，当在每帧渲染之前，系统捕获输入设备状态，并根据这些状态对场景中的物体和摄象机进行控制。 
buffered：在一个按键放开之前，只处理一次输入信息。 
             例如呼出主菜单。适合于GUI界面的情况（如设置菜单），输入设备状态可以被发送到各GUI元素进行处理（如按钮被按下）。

这个例子试图说明缓冲输入和非缓冲输入的区别，但是让我困惑的是为什么采用了缓冲输入系统还能响应持续按键呢？编译后运行按住WSAD照样移动摄像机。