小球和窗口边框碰撞的问题。

[cryinghawk]

请问各位大虾。。用C++写的
画一个圆形，圆形自由移动。圆形可以和窗口边框碰撞然后反弹。。。。
主要是碰撞反弹的问题。。
麻烦各位解决下。。。。。
O(∩_∩)O


我下课来看贴，，，结贴。。。。。。。。。


先谢谢了。。。。。

[三文鱼也会飞]

设置好边际，当小球的圆心距离边际一个半径的时候，计算角度，反弹

[shyli]

设置一个Vx, Vy，表明X和Y轴方向的速度。
碰到左或右边框则Vx=-Vx；
碰到上或下边框则Vy=-Vy；
碰到4个角则Vx=-Vx，Vy=-Vy。

[cryinghawk]

为什么没人理我呢，，，，，
郁闷啊。。。

[星羽]

帮你写了个，自己改改吧

win32程序

// win32.cpp : Defines the entry point for the application.
//


#include <windowsx.h>
#include <tchar.h>

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

HPEN gPen1;
HPEN gPen2;
HBRUSH gBrush;

int WINAPI _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)
{
	MSG msg;
    WNDCLASSEX wcex;

    ZeroMemory(&wcex, sizeof(wcex));
    wcex.cbSize         = sizeof(WNDCLASSEX);
    wcex.style			= CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc	= WndProc;
    wcex.cbClsExtra		= 0;
    wcex.cbWndExtra		= 0;
    wcex.hInstance		= hInstance;
    wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszClassName	= TEXT("Win32");

    RegisterClassEx(&wcex);

    HWND hWnd = CreateWindow(
        TEXT("Win32"), 
        TEXT("Win32"), 
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, 
        0, 
        CW_USEDEFAULT, 
        0, 
        NULL, 
        NULL, 
        hInstance, 
        NULL);

    if (!hWnd)
        return FALSE;

    gPen1 = CreatePen(PS_SOLID, 1, RGB(198, 198, 198));
    gPen2 = CreatePen(PS_SOLID, 1, RGB(0, 0, 255));
    gBrush = CreateSolidBrush(RGB(198, 198, 198));

    ShowWindow(hWnd, nCmdShow);
    UpdateWindow(hWnd);

    SetTimer(hWnd, 1, 10, NULL);

	while (GetMessage(&msg, NULL, 0, 0))
	{
        TranslateMessage(&msg);
        DispatchMessage(&msg);
	}

    DeletePen(gPen1);
    DeletePen(gPen2);
    DeleteBrush(gBrush);

	return (int) msg.wParam;
}

long gx = 100;
long gy = 100;
long gSpeedx = 10;
long gSpeedy = 10;

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	PAINTSTRUCT ps;
	HDC hdc;

	switch (message)
	{
	case WM_PAINT:
        {
            RECT rectClient;
            GetClientRect(hWnd, &rectClient);

		    hdc = BeginPaint(hWnd, &ps);

            SelectBrush(hdc, gBrush);
            SelectPen(hdc, gPen1);

            Ellipse(hdc, gx, gy, gx + 50, gy + 50);
            
            gx += gSpeedx;
            gy += gSpeedy;

            if (gx < rectClient.left || gx + 25 > rectClient.right)
            {
                gSpeedx = -gSpeedx;
                break;
            }

            if (gy < rectClient.top || gy + 25 > rectClient.bottom)
            {
                gSpeedy = -gSpeedy;
                break;
            }

            SelectPen(hdc, gPen2);
            Ellipse(hdc, gx, gy, gx + 50, gy + 50);

		    EndPaint(hWnd, &ps);
        }
		break;
    case WM_ERASEBKGND :
        {
            RECT rect;
            hdc = (HDC)wParam;
            GetClipBox(hdc, &rect);
            FillRect(hdc, &rect, gBrush);
            return 0;
        }
        break;
    case WM_TIMER :
        {
            if (wParam == 1)
            {
                InvalidateRect(hWnd, NULL, FALSE);
            }
        }
        break;
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
	default:
		return DefWindowProc(hWnd, message, wParam, lParam);
	}
	return 0;
}

[Felix.Peng]

楼上的牛人呀！顶一个!

[icesky_ff]

星羽还是很强悍啊