简单的重力

CODE:

/***************************************************************************************************** 
* File name:               Game.cpp 
* Create time:             2015/03/28
* Module:                  View 
* Author:                  zengqh 
* Blog:                    http://blog.youkuaiyun.com/aimyton 
* --------------------------------------------------------------------------------------------------- 
* Memo: 
* 
*****************************************************************************************************/  
#include "Game.h"
/***************************************************************************************************** 
*                                  Macro and Struct definition 
*****************************************************************************************************/  
#define DYNAMIC_RANGE		(200)
#define ACCELERATION		(1000)
/***************************************************************************************************** 
*                                  Global variables 
*****************************************************************************************************/
extern HINSTANCE HInstance;
f32 g_start_speed = 0.0f;
f32 g_circle_time = 0.0f;
/***************************************************************************************************** 
*                                  Global function declare 
*****************************************************************************************************/  

/***************************************************************************************************** 
*                                  Global function definition 
*****************************************************************************************************/

/***************************************************************************************************** 
*                                  Class declare 
******************************************************************************************************/
Game::Game()
: m_surface_width(640)
, m_surface_height(480)
, m_hwnd(0)
, m_backbuff_bitmap(0)
, m_back_buffer(NULL)
, m_should_exit_game(false)
, m_start_render_time(0)
, m_min_y(480)
{
	g_circle_time = 2 * sqrtf(2 * DYNAMIC_RANGE / (float)ACCELERATION);
	g_start_speed = ACCELERATION * (g_circle_time / 2.0f);
}

Game::~Game()
{

}

bool Game::Initalize()
{
	if(!initDriver()) return false;

	return true;
}

bool Game::UnInitialize()
{
	return true;
}

bool Game::Loop()
{
	handleMessage();
	return true;
}

void Game::handleMessage()
{
	MSG msg;
	::ZeroMemory(&msg, sizeof(MSG));

	static float lastTime = (float)timeGetTime(); 

	while(msg.message != WM_QUIT)
	{
		if(m_should_exit_game)
		{
			PostMessage(m_hwnd, WM_QUIT, 0, 0);
		}

		if(::PeekMessage(&msg, 0, 0, 0, PM_REMOVE))
		{
			::TranslateMessage(&msg);
			::DispatchMessage(&msg);
		}
		else
		{	
			float timeLog=1.0f / 100.0f;
			float currTime	=(float)timeGetTime();
			float timeDelta	 =(currTime-lastTime) * 0.001f;
			if(timeDelta < timeLog)
			{
				float sleep=1000 * (timeLog - timeDelta);
				Sleep(sleep); 
			}

			currTime =(float)timeGetTime();
			timeDelta =(currTime-lastTime)*0.001f;

			gameLoop(timeDelta);
			lastTime = currTime;
		}
	}
}

void Game::gameLoop(float time_delta)
{
	frameStarted();
	render();
	frameEnded();

	swap();
}

void Game::frameStarted()
{
	memset(m_back_buffer, 0x0, m_surface_width * m_surface_height * 4);
}

void Game::render()
{
	renderTextFixed(m_surface_width / 2 - 200, m_surface_height / 2, "hello world");
	renderTextBottom(m_surface_width / 2, m_surface_height / 2, "hello world");
	renderTextCenter(m_surface_width / 2 - 100, m_surface_height / 2, "hello world");
}

void Game::frameEnded()
{

}

void Game::swap()
{
	BitBlt(m_hdc, 0, 0, m_surface_width, m_surface_height, m_bdc, 0, 0, SRCCOPY);
}

bool Game::initDriver()
{
	createWindow();
	createBackBuffer();

	return true;
}

bool Game::createWindow()
{
	WNDCLASS wc;

	wc.style         = CS_HREDRAW | CS_VREDRAW;
	wc.lpfnWndProc   = (WNDPROC)WndProc; 
	wc.cbClsExtra    = 0;
	wc.cbWndExtra    = 0;
	wc.hInstance     = HInstance;
	wc.hIcon         = LoadIcon(0, IDI_APPLICATION);
	wc.hCursor       = LoadCursor(0, IDC_ARROW);
	wc.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
	wc.lpszMenuName  = 0;
	wc.lpszClassName = "GameDemo";

	if( !RegisterClass(&wc) ) 
	{
		::MessageBox(0, "RegisterClass() - FAILED", 0, 0);
		return false;
	}

	RECT rect = {0, 0, m_surface_width, m_surface_height};

	::AdjustWindowRect(&rect, WS_OVERLAPPEDWINDOW, FALSE);

	HWND hwnd = 0;
	hwnd = ::CreateWindow("GameDemo", "GameDemo", 
		WS_OVERLAPPEDWINDOW,
		0, 0, rect.right - rect.left, rect.bottom - rect.top,
		0 /*parent hwnd*/, 0 /* menu */, HInstance, 0 /*extra*/); 

	if( !hwnd )
	{
		::MessageBox(0, "CreateWindow() - FAILED", 0, 0);
		return false;
	}

	m_hwnd = hwnd;
	m_hdc = ::GetDC(m_hwnd);

	::ShowWindow(hwnd, SW_SHOW);
	::UpdateWindow(hwnd);

	return true;
}

bool Game::createBackBuffer()
{
	BITMAPINFO bitmap_info = {0};

	bitmap_info.bmiHeader.biSize					= sizeof(bitmap_info);
	bitmap_info.bmiHeader.biWidth					= m_surface_width;
	bitmap_info.bmiHeader.biHeight					= m_surface_height;
	bitmap_info.bmiHeader.biPlanes					= 1;
	bitmap_info.bmiHeader.biSizeImage				= 0;
	bitmap_info.bmiHeader.biXPelsPerMeter			= 0;
	bitmap_info.bmiHeader.biYPelsPerMeter			= 0;
	bitmap_info.bmiHeader.biClrUsed					= 0;
	bitmap_info.bmiHeader.biClrImportant			= 0;
	bitmap_info.bmiHeader.biBitCount				= 32;
	bitmap_info.bmiHeader.biCompression				= BI_RGB;

	m_bdc = CreateCompatibleDC(m_hdc);

	m_backbuff_bitmap = CreateDIBSection(
		NULL,
		&bitmap_info,
		0,
		(void**)&m_back_buffer,
		0,
		0);

	::SelectObject(m_bdc, m_backbuff_bitmap);

	return (m_back_buffer != NULL ? true : false);
}

void Game::renderTextFixed(int x, int y, char* str)
{
	::TextOutA(m_bdc, x, y, str, strlen(str));
}

void Game::renderTextBottom(int x, int y, char* str)
{
	if(m_start_render_time == 0)
	{
		m_start_render_time = GetTickCount();
	}
	else
	{
		u32 curr_time = GetTickCount();
		
		float time_delta = (curr_time - m_start_render_time) / 1000.0f;

		float one_circle_time = time_delta - (u32)(time_delta / g_circle_time) * g_circle_time;
		float accer = ACCELERATION;

		y += -g_start_speed * one_circle_time + 0.5f * accer * one_circle_time * one_circle_time;

		::TextOutA(m_bdc, x, y, str, strlen(str));
	}
}

void Game::renderTextCenter(int x, int y, char* str)
{
	if(m_start_render_time == 0)
	{
		m_start_render_time = GetTickCount();
	}
	else
	{
		u32 curr_time = GetTickCount();

		float time_delta = (curr_time - m_start_render_time) / 1000.0f;

		float one_circle_time = time_delta - (u32)(time_delta / g_circle_time) * g_circle_time;
		float accer = ACCELERATION;

		y += -g_start_speed * one_circle_time + 0.5f * accer * one_circle_time * one_circle_time;

		if(y < m_min_y)
		{
			m_min_y = y;
		}

		y += (DYNAMIC_RANGE >> 1);

		::TextOutA(m_bdc, x, y, str, strlen(str));
	}
}

LRESULT CALLBACK Game::WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	switch( msg )
	{
	case WM_DESTROY:
		::PostQuitMessage(0);
		break;
	}
	return ::DefWindowProc(hwnd, msg, wParam, lParam);
}
/***************************************************************************************************** 
*                                  Class definition 
*****************************************************************************************************/

/***********************************End of File*******************************************************/