/Samples/Chap14/Bounce/Bounce.d

/+
 + Copyright (c) Charles Petzold, 1998.
 + Ported to the D Programming Language by Andrej Mitrovic, 2011.
 +/

module Bounce;

import core.memory;
import core.runtime;
import core.thread;
import std.algorithm : max, min;
import std.conv;
import std.math;
import std.range;
import std.string;
import std.utf;

auto toUTF16z(S)(S s)
{
    return toUTFz!(const(wchar)*)(s);
}

pragma(lib, "gdi32.lib");

import core.sys.windows.windef;
import core.sys.windows.winuser;
import core.sys.windows.wingdi;
import core.sys.windows.winbase;

enum ID_TIMER = 1;
string appName     = "Bounce";
string description = "Bouncing Ball";
HINSTANCE hinst;

extern (Windows)
int WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int iCmdShow)
{
    int result;

    try
    {
        Runtime.initialize();
        result = myWinMain(hInstance, hPrevInstance, lpCmdLine, iCmdShow);
        Runtime.terminate();
    }
    catch (Throwable o)
    {
        MessageBox(null, o.toString().toUTF16z, "Error", MB_OK | MB_ICONEXCLAMATION);
        result = 0;
    }

    return result;
}

int myWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int iCmdShow)
{
    hinst = hInstance;
    HACCEL hAccel;
    HWND hwnd;
    MSG  msg;
    WNDCLASS wndclass;

    wndclass.style         = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc   = &WndProc;
    wndclass.cbClsExtra    = 0;
    wndclass.cbWndExtra    = 0;
    wndclass.hInstance     = hInstance;
    wndclass.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = cast(HBRUSH) GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName  = appName.toUTF16z;
    wndclass.lpszClassName = appName.toUTF16z;

    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, "This program requires Windows NT!", appName.toUTF16z, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(appName.toUTF16z,              // window class name
                        description.toUTF16z,          // window caption
                        WS_OVERLAPPEDWINDOW,           // window style
                        CW_USEDEFAULT,                 // initial x position
                        CW_USEDEFAULT,                 // initial y position
                        CW_USEDEFAULT,                 // initial x size
                        CW_USEDEFAULT,                 // initial y size
                        NULL,                          // parent window handle
                        NULL,                          // window menu handle
                        hInstance,                     // program instance handle
                        NULL);                         // creation parameters

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

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

    return msg.wParam;
}

extern (Windows)
LRESULT WndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
{
    static HBITMAP hBitmap;
    static int cxClient, cyClient, xCenter, yCenter, cxTotal, cyTotal,
               cxRadius, cyRadius, cxMove, cyMove, xPixel, yPixel;
    HBRUSH hBrush;
    HDC hdc, hdcMem;
    int iScale;

    switch (iMsg)
    {
        case WM_CREATE:
            hdc    = GetDC(hwnd);
            xPixel = GetDeviceCaps(hdc, ASPECTX);
            yPixel = GetDeviceCaps(hdc, ASPECTY);
            ReleaseDC(hwnd, hdc);

            SetTimer(hwnd, ID_TIMER, 50, NULL);
            return 0;

        case WM_SIZE:
            xCenter = (cxClient = LOWORD(lParam)) / 2;
            yCenter = (cyClient = HIWORD(lParam)) / 2;

            iScale = min(cxClient * xPixel, cyClient * yPixel) / 16;

            cxRadius = iScale / xPixel;
            cyRadius = iScale / yPixel;

            cxMove = max(1, cxRadius / 2);
            cyMove = max(1, cyRadius / 2);

            cxTotal = 2 * (cxRadius + cxMove);
            cyTotal = 2 * (cyRadius + cyMove);

            if (hBitmap)
                DeleteObject(hBitmap);

            hdc     = GetDC(hwnd);
            hdcMem  = CreateCompatibleDC(hdc);
            hBitmap = CreateCompatibleBitmap(hdc, cxTotal, cyTotal);
            ReleaseDC(hwnd, hdc);

            SelectObject(hdcMem, hBitmap);
            Rectangle(hdcMem, -1, -1, cxTotal + 1, cyTotal + 1);

            hBrush = CreateHatchBrush(HS_DIAGCROSS, 0L);
            SelectObject(hdcMem, hBrush);
            SetBkColor(hdcMem, RGB(255, 0, 255));
            Ellipse(hdcMem, cxMove, cyMove, cxTotal - cxMove, cyTotal - cyMove);
            DeleteDC(hdcMem);
            DeleteObject(hBrush);
            return 0;

        case WM_TIMER:

            if (!hBitmap)
                break;

            hdc    = GetDC(hwnd);
            hdcMem = CreateCompatibleDC(hdc);
            SelectObject(hdcMem, hBitmap);

            BitBlt(hdc, xCenter - cxTotal / 2,
                   yCenter - cyTotal / 2, cxTotal, cyTotal,
                   hdcMem, 0, 0, SRCCOPY);

            ReleaseDC(hwnd, hdc);
            DeleteDC(hdcMem);

            xCenter += cxMove;
            yCenter += cyMove;

            if ((xCenter + cxRadius >= cxClient) || (xCenter - cxRadius <= 0))
                cxMove = -cxMove;

            if ((yCenter + cyRadius >= cyClient) || (yCenter - cyRadius <= 0))
                cyMove = -cyMove;

            return 0;

        case WM_DESTROY:

            if (hBitmap)
                DeleteObject(hBitmap);

            KillTimer(hwnd, ID_TIMER);
            PostQuitMessage(0);
            return 0;

        default:
    }

    return DefWindowProc(hwnd, iMsg, wParam, lParam);
}