Графика в Visual c

#include <Windows.h>
#include <cmath>
 
BOOL CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
void Draw(HWND);
 
int APIENTRY _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                       LPTSTR lpCmdLine, int nCmdShow)
{
    MSG msg;
    DialogBox(hInstance, MAKEINTRESOURCE(IDD_DIALOG1), NULL, WndProc);
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return (int)msg.wParam;
}
int count[10] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
HBRUSH brush[10] = 
    {CreateSolidBrush(RGB(255, 255, 0)),   CreateSolidBrush( RGB(255,  0,   255)),
     CreateSolidBrush( RGB(0,    255, 255)), CreateSolidBrush(RGB(128, 255, 0)),
     CreateSolidBrush( RGB(0,    0,    255)), CreateSolidBrush(RGB(255, 255, 128)),
     CreateSolidBrush( RGB(255, 128, 255)), CreateSolidBrush(RGB(128, 255, 255)),
     CreateSolidBrush( RGB(128, 255, 128)), CreateSolidBrush(RGB(0,    128, 255))};
BOOL CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch(message)
    {
        case WM_COMMAND:
            if(LOWORD(wParam) == IDC_BUTTON1)
            {
                int i;
                for(i = 0; i < 10; count[i] ^= count[i], ++i);
                for(i = 0; i < 360; ++count[rand() % 10], ++i);
                Draw(hWnd);
            }
            break;
        case WM_ACTIVATE:
            Draw(hWnd);
            break;
        case WM_CLOSE:
            PostQuitMessage(WM_QUIT);
            break;
    }
    return FALSE;
}
void Draw(HWND hWnd)
{
    HDC cdc = GetDC(hWnd);
    int i, val(count[0]), prevx(20), prevy(235);
    RECT* rect = new RECT;
    GetClientRect(hWnd, rect);
    for(i = 0; i < 10; val += count[++i])
    {
        SelectObject(cdc, brush[i]);
        Pie(cdc, rect->left + 20, rect->top + 20, rect->right - 20, rect->bottom - 20, 
            235 - (int)(215 * cos(val * (3.14159 / 180))), 
            235 - (int)(215 * sin(val * (3.14159 / 180))),
            prevx, prevy);
        prevx = 235 - (int)(215 * cos(val * (3.14159 / 180)));
        prevy = 235 - (int)(215 * sin(val * (3.14159 / 180)));  
    }
    ReleaseDC(hWnd, cdc);
}