GLUT的一个简洁OO封装

#ifndef GLUT_APP_H
#define GLUT_APP_H

class GlutApp 
{
public:
	typedef void (*MenuFuncPtr)(void);

	struct MenuEntry 
	{
		int id;
		const char* str;
		MenuFuncPtr fun;
	};

	// 当前 App 实例指针,指向子类实例
	static GlutApp* s_pCurrentApp;

	// 右键菜单 项数最大值
	static const int MAX_MENU = 32;

	// ctor
	GlutApp();

	// getter and setters:
	static void initGlut(int argc, char** argv) { s_argc = argc; s_argv = argv; }

	void setDisplayMode(unsigned int mode) { m_displayMode = mode; }

	void setWindowsSize(int w, int h) { m_winWidth = w; m_winHeight = h; }

	int getWindowWidth() { return m_winWidth; }

	int getWindowHeight() { return m_winHeight; }

	void setWindowsPos(int x, int y) { m_winPosX = x; m_winPosY = y; }

	void setTitle(char *title) { m_title = title; }

	void run();

	void addRightMenu(const char *str, MenuFuncPtr fun);

	// 初始化
	virtual void onInit(){}

	//////////////////////////////////////////////////////////////////////////
	// GLUT delegate callbacks:

	// 空闲函数
	virtual void onIdle(){}

	// 图形显示（OpenGL绘图指令）
	virtual void onDisplay() = 0; // 子类必须重写；不能实例化该类

	// 窗口大小改变
	virtual void onResize(int w, int h){}

	//////////////////////////////////////////////////////////////////////////
	// 键盘事件响应 方法:

	// 一般按键（可打印字符，ESC）
	virtual void onKey(unsigned char key, int x, int y){}

	// 一般按键 按下
	virtual void onKeyDown(unsigned char key, int x, int y) {}

	// 特殊按键（除一般按键外按键）
	virtual void onSpecialKey(int key, int x, int y){}

	// 特殊按键按下
	virtual void onSpecialKeyDown(int key, int x, int y){}

	//////////////////////////////////////////////////////////////////////////
	// 鼠标事件响应 方法:

	// 鼠标按键
	//! @param button: The button parameter is one of GLUT LEFT BUTTON, GLUT MIDDLE BUTTON, or GLUT RIGHT BUTTON.
	//! @param state: The state parameter is either GLUT UP or GLUT DOWN indicating 
	//                 whether the callback was due to a release or press respectively.
	virtual void onMousePress(int button, int state, int x, int y){}

	// 鼠标移动
	virtual void onMouseMove(int x, int y){}

	// 鼠标拖动
	virtual void onMousePressMove(int x,int y){}

	//////////////////////////////////////////////////////////////////////////
	// 定时器相关 方法：
	virtual void onTimer() {}

	void setTimer(int delay, int period = 0);

protected:
	void registerMenus();

	// actual GLUT callback functions:
	static void KeyboardCallback(unsigned char key, int x, int y);

	static void KeyboardUpCallback(unsigned char key, int x, int y);

	static void SpecialKeyboardCallback(int key, int x, int y);

	static void SpecialKeyboardUpCallback(int key, int x, int y);

	static void ReshapeCallback(int w, int h);

	static void IdleCallback();

	static void MouseFuncCallback(int button, int state, int x, int y);

	static void	MotionFuncCallback(int x,int y);

	static void MousePassiveCallback(int x, int y);

	static void DisplayCallback();

	static void MenuCallback(int menuId);
	
	static void TimerCallback(int period);
private:
	unsigned int m_displayMode;

	// for glutInit
	static int s_argc;
	static char** s_argv;

	char *m_title;

	// for glutSetWindowSize
	int m_winWidth;
	int m_winHeight;

	// for windows position
	int m_winPosX;
	int m_winPosY;

	// for menus:
	int       m_menuCount;
	MenuEntry m_menuEntry[MAX_MENU];

	// for timer:
	int m_delay;
	int m_period;
};

#endif // GLUT_APP_H

#include <gl/glut.h>
#include <assert.h>
#include <stdio.h>

#include "GlutApp.h"

int GlutApp::s_argc = 0;

char** GlutApp::s_argv = 0;

GlutApp* GlutApp::s_pCurrentApp = 0;

int g_iLastWindow = 0;

void GlutApp::run()
{
	GlutApp* lastApp = GlutApp::s_pCurrentApp;
	GlutApp::s_pCurrentApp = this;

	GlutApp* app = GlutApp::s_pCurrentApp;
	assert(app);

	int screenW = glutGet(GLUT_SCREEN_WIDTH);
	int screenH = glutGet(GLUT_SCREEN_HEIGHT);

	if (!app->m_winWidth)
	{
		app->m_winWidth = screenW / 2;
		app->m_winHeight = screenH / 2;
	}
	
	if (!app->m_winPosX)
	{
		app->m_winPosX = (screenW - app->m_winWidth) / 2;
		app->m_winPosY = (screenH - app->m_winHeight) / 2;
	}

	if (!lastApp) // first time calling Glut::run().
	{
		// glutInit that should only be called exactly once in a GLUT program.
		glutInit(&this->s_argc, this->s_argv);

		glutInitDisplayMode(this->m_displayMode);
		glutInitWindowPosition(app->m_winPosX, app->m_winPosY);
		glutInitWindowSize(app->m_winWidth, app->m_winHeight);

		glutCreateWindow(app->m_title);
		g_iLastWindow = glutGetWindow();
		// printf("create window: %d\n", g_iLastWindow);
	}
	else
	{
		glutDestroyWindow(g_iLastWindow);

		glutInitDisplayMode(this->m_displayMode);
		glutInitWindowPosition(app->m_winPosX, app->m_winPosY);
		glutInitWindowSize(app->m_winWidth, app->m_winHeight);

		glutCreateWindow(app->m_title);
		g_iLastWindow = glutGetWindow();
		// printf("create window: %d\n", g_iLastWindow);
	}

	app->onInit();

	// register keyboard callbacks
	glutKeyboardFunc(GlutApp::KeyboardCallback);
	glutKeyboardUpFunc(GlutApp::KeyboardUpCallback);
	glutSpecialFunc(GlutApp::SpecialKeyboardCallback);
	glutSpecialUpFunc(GlutApp::SpecialKeyboardUpCallback);

	// register mouse callbacks
	glutMouseFunc(GlutApp::MouseFuncCallback);
	glutMotionFunc(GlutApp::MotionFuncCallback);
	glutPassiveMotionFunc(GlutApp::MousePassiveCallback);

	// register menus:
	registerMenus();

	// regitser windows resize callback
	glutReshapeFunc(GlutApp::ReshapeCallback);

	// register render callback
	glutDisplayFunc(GlutApp::DisplayCallback);

	// register timer callbacks:
	if (app->m_delay)
	{
		glutTimerFunc(app->m_delay, GlutApp::TimerCallback, app->m_period);
	}

	// register idle callback
	glutIdleFunc(GlutApp::IdleCallback);

	GlutApp::IdleCallback();

	glutMainLoop();
}

GlutApp::GlutApp()
{
	m_displayMode = GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH | GLUT_STENCIL;
	m_menuCount = 0;
	m_delay = 0;
	m_period = 0;

	m_winPosX = 0;
	m_winPosY = 0;
	m_winWidth = 0;
	m_winHeight = 0;
}

void GlutApp::KeyboardCallback( unsigned char key, int x, int y )
{
	GlutApp::s_pCurrentApp->onKey(key,x,y);
}

void GlutApp::KeyboardUpCallback( unsigned char key, int x, int y )
{
	GlutApp::s_pCurrentApp->onKeyDown(key,x,y);
}

void GlutApp::SpecialKeyboardCallback( int key, int x, int y )
{
	GlutApp::s_pCurrentApp->onSpecialKey(key,x,y);
}

void GlutApp::SpecialKeyboardUpCallback( int key, int x, int y )
{
	GlutApp::s_pCurrentApp->onSpecialKeyDown(key,x,y);
}

void GlutApp::ReshapeCallback( int w, int h )
{
	GlutApp::s_pCurrentApp->setWindowsSize(w, h);
	GlutApp::s_pCurrentApp->onResize(w,h);
}

void GlutApp::IdleCallback()
{
	GlutApp::s_pCurrentApp->onIdle();
}

void GlutApp::MouseFuncCallback( int button, int state, int x, int y )
{
	GlutApp::s_pCurrentApp->onMousePress(button,state,x,y);
}

void GlutApp::MotionFuncCallback( int x,int y )
{
	GlutApp::s_pCurrentApp->onMousePressMove(x,y);
}

void GlutApp::MousePassiveCallback( int x, int y )
{
	GlutApp::s_pCurrentApp->onMouseMove(x, y);
}

void GlutApp::DisplayCallback( void )
{
	GlutApp::s_pCurrentApp->onDisplay();
}

void GlutApp::addRightMenu( const char *str, MenuFuncPtr fun )
{
	m_menuEntry[m_menuCount].id = m_menuCount;
	m_menuEntry[m_menuCount].str = str;
	m_menuEntry[m_menuCount].fun = fun;
	m_menuCount++;
}

void GlutApp::registerMenus()
{
	if (m_menuCount > 0)
	{
		glutCreateMenu(GlutApp::MenuCallback);
		for (int i=0; i<m_menuCount; ++i)
		{
			glutAddMenuEntry(m_menuEntry[i].str, m_menuEntry[i].id);
		}
		glutAttachMenu(GLUT_RIGHT_BUTTON);
	}
}

void GlutApp::MenuCallback( int menuId )
{
	for (int i=0; i<GlutApp::s_pCurrentApp->m_menuCount; ++i)
	{
		if (menuId == GlutApp::s_pCurrentApp->m_menuEntry[i].id)
		{
			GlutApp::s_pCurrentApp->m_menuEntry[i].fun();
		}
	}
}

void GlutApp::setTimer( int delay, int period )
{
	this->m_delay = delay;
	this->m_period = period;
}

void GlutApp::TimerCallback( int period )
{
	// printf("Timer Alarm!\n");
	GlutApp::s_pCurrentApp->onTimer();
	if (period)
	{
		glutTimerFunc(period, GlutApp::TimerCallback, period);
	}
}