// Circles.cpp ///////////////////////////////////////////////////////////////// This example is used to demonstrate the movement and collision of two// balls with the bounds of the screen and each other.  This program uses// a frame based loop rather than relying on windows messages, in order to // regulate the speed of the balls.//////////////////////////////////////////////////////////////////////////////#define WIN32_LEAN_AND_MEAN				// We don't need any MFC objects// INCLUDES ////////////////////////////////////////////////////////////////#include <windows.h>					// Include std windows library#include <time.h>#include <stdlib.h>#include "Ball.h"						// Our Ball Class// DEFINES /////////////////////////////////////////////////////////////////#define WINDOW_CLASS_NAME "WINCLASS1"	// The name of our window class#define WINDOW_WIDTH 640				// The initial width of the window#define WINDOW_HEIGHT 480				// The initial height of the window// GLOBALS /////////////////////////////////////////////////////////////////HWND g_main_window_handle = NULL;		// globally track main windowHINSTANCE hinstance_app = NULL;			// globally track hinstance// FUNCTIONS ///////////////////////////////////////////////////////////////LRESULT CALLBACK WindowProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam){	// what is the message 	switch(msg)	{			// Make sure that the user can not resize the screen smaller than 400 x 300		case WM_GETMINMAXINFO:		{			// Retrieve the window size info from the lParam			LPMINMAXINFO lpnmi = (LPMINMAXINFO)lParam;			// Create a new point set to the min width and min height of the screen			POINT ts;			ts.x = 400;			ts.y = 300;			// Set the minTrackSize (the smallest size the window can be set to) 			// to the new POINT			lpnmi->ptMinTrackSize = ts;		}		break;		case WM_DESTROY: 		{			// Kill the application, this sends a WM_QUIT message 			PostQuitMessage(0);			// Return success			return(0);		} 		break;		default:break;	} // end switch	// Process any messages that we didn't take care of 	return (DefWindowProc(hWnd, msg, wParam, lParam));} // end WinProc// WINMAIN /////////////////////////////////////////////////////////////////int WINAPI WinMain(	HINSTANCE hinstance,					HINSTANCE hprevinstance,					LPSTR lpcmdline,					int ncmdshow){	WNDCLASSEX winclass; // this will hold the class we create	HWND	   hWnd;	 // generic window handle	MSG		   msg;		 // generic message	// first fill in the window class stucture	winclass.cbSize         = sizeof(WNDCLASSEX);	winclass.style			= CS_DBLCLKS | CS_OWNDC | 							  CS_HREDRAW | CS_VREDRAW;	winclass.lpfnWndProc	= WindowProc;	winclass.cbClsExtra		= 0;	winclass.cbWndExtra		= 0;	winclass.hInstance		= hinstance;	winclass.hIcon			= NULL;	winclass.hCursor		= LoadCursor(NULL, IDC_ARROW); 	winclass.hbrBackground	= (HBRUSH)GetStockObject(BLACK_BRUSH);	winclass.lpszMenuName	= NULL;	winclass.lpszClassName	= WINDOW_CLASS_NAME;	winclass.hIconSm        = NULL;	// Save hinstance globally	hinstance_app = hinstance;	// Register the window class	if (!RegisterClassEx(&winclass))		return(0);	// Create the window	if (!(hWnd = CreateWindowEx(NULL,						// extended window style								WINDOW_CLASS_NAME,			// class								"CIRCLES",					// title								WS_OVERLAPPEDWINDOW | WS_VISIBLE,	// window style					 			100,20,						// initial x,y								WINDOW_WIDTH,WINDOW_HEIGHT,	// initial width, height								NULL,						// handle to parent 								NULL,						// handle to menu								hinstance,					// instance of this application								NULL)))						// extra creation parms		return(0);	// Save main window handle	g_main_window_handle = hWnd;	HDC	hDC, hMemDC;		// Handles to a device context	HBITMAP hOldBmp, hBmp;	// Bitmaps used for blitting the screen	// Seed the random number generator	srand(time(0));	// Create the balls	Ball ball1;	Ball ball2;	// Make some new pens and brushes for drawing the balls	HPEN green_pen = CreatePen(PS_SOLID, 1, RGB(0,255,0));	HBRUSH green_brush = CreateSolidBrush(RGB(0,255,0));	HPEN blue_pen = CreatePen(PS_SOLID, 1, RGB(0,0,255));	HBRUSH blue_brush = CreateSolidBrush(RGB(0,0,255));		// Create a variable to store the time a collision happened.  This will be used to display 	// a collision message to the screen for 1.5 seconds	DWORD dwCollisionTime = 0;	// Enter main loop	while(TRUE)	{		// Get the client area		RECT cr;		GetClientRect(hWnd, &cr);		// Test if there is a message in queue, if so get it		if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))		{ 			// Test if this is a quit			if (msg.message == WM_QUIT)			   break;			// Translate any messages			TranslateMessage(&msg);			// Send the message to the window proc			DispatchMessage(&msg);		} // end if		// Get the time this function began executing		DWORD dwStartTime = GetTickCount();		// Get the display device context		hDC = GetDC(hWnd);		// Get the client retangle for the display bitmap		GetClientRect(hWnd, &cr);		// Create a new memory device context		hMemDC = CreateCompatibleDC(hDC);		// Create a bitmap for the memory DC		hBmp = CreateCompatibleBitmap(hDC, cr.right, cr.bottom);		// Attach the new bitmap to the memory DC		hOldBmp = (HBITMAP)SelectObject(hMemDC, hBmp); 				// Move the balls		ball1.move();		ball2.move();		// Check for a collision with the wall		ball1.checkWallCollision();		ball2.checkWallCollision();		// Check to see if the two balls collided, and if it's been more than 		// 500 milliseconds since the last collision, to ensure the balls 		// don't 'stick' to each other		if (GetTickCount() - dwCollisionTime > 500 && ball1.checkBallCollision(ball2))		{			// They collided, so set the collision time to the current time			dwCollisionTime = GetTickCount();		} // end if		// Display a message showing the collision for 1.5 seconds after a collision has occured		if (GetTickCount() - dwCollisionTime < 1500)		{			// The string we want to output			char string[] = "Collision Detected";			// Set the Colors for outputing text to the screen			// Set the foreground color to green			SetTextColor(hMemDC, RGB(0,255,0));			// Set the background color to black			SetBkColor(hMemDC, RGB(0,0,0));			// Set the transparency mode to OPAQUE			SetBkMode(hMemDC, OPAQUE);			// Show the message at the bottom center of the screen			TextOut(hMemDC,(cr.right - cr.left) / 2 - (strlen(string) / 2) * 7,					cr.bottom - 15, string, strlen(string));		} // end if		// Save the original pen and brush and select the Green ones into the DC		HPEN original_pen = (HPEN)SelectObject(hMemDC, green_pen);		HBRUSH original_brush = (HBRUSH)SelectObject(hMemDC, green_brush);		// Draw the first ball to the screen		ball1.show(hMemDC);		// Select the Blue pen and brush into the DC		SelectObject(hMemDC, blue_pen);		SelectObject(hMemDC, blue_brush);		// Draw the second ball to the screen		ball2.show(hMemDC);		// Select the original drawing tools back into the DC		SelectObject(hMemDC, original_pen);		SelectObject(hMemDC, original_brush);		// Blit the new bitmap to the screen		BitBlt(hDC, cr.left, cr.top, cr.right, cr.bottom, hMemDC, cr.left, cr.top, SRCCOPY);		// Attach the old bitmap to the memory DC		SelectObject(hMemDC, hOldBmp);		// Delete the memory DC		DeleteDC(hMemDC);		// Delete the bitmap		DeleteObject(hBmp);		// Release the display DC		ReleaseDC(hWnd, hDC); 		// Wait until a frame phase has passed		while((GetTickCount() - dwStartTime) < 33); 	} // end while	// Delete all of the pens and brushes that we created	DeleteObject(green_pen);	DeleteObject(green_brush);	DeleteObject(blue_pen);	DeleteObject(blue_brush);	// Return to Windows	return(msg.wParam);} // end WinMain////////////////////////////////////////////////////////////////////////////