Boing64 (OpenGL layered animation)

[Patrice Terrier]

Do you remember that?



The AMIGA Boing Ball, was a mythical object in the computer industry created during a night at the 1984 CES by Dale Luck and R. J. Mical.



This reworked 64-bit version is only 19 Kb in size including the icon resource.
It is using the same concept exposed in the T-Rex animation posted here:
https://www.codeproject.com/Articles/763207/T-Rex-animation
except that the multi-frame animation has been replaced by a real 3D object.

It uses a popup transparent layered window to render the sphere animation with OpenGL.
Not much to say about the C++ source code, that should be self explanatory for those familiar with the low level procedural SDK programming style.

RenderAnimation is the masterpiece where the Amiga logo and the OpenGL 3D sphere are mixed together into the same DC using DrawAndSetupAlphaChannel.

Code: [Select]

void RenderAnimation(IN HWND hWnd) {
    RECT rw = { 0 };
    BLENDFUNCTION bf = { 0 };
    POINT lp = { 0 }, ptSrc = { 0 };
    SIZEL lpSize = { 0 };

    LONG_PTR graphics = 0, imgAttr = 0, lpCallback = 0, callbackdata = 0;

    static long imgW, imgH, xDir, yDir;

    GetWindowRect(hWnd, &rw);
    lpSize.cx = rw.right - rw.left; lpSize.cy = rw.bottom - rw.top;
    lp.x = rw.left; lp.y = rw.top;

    HDC DesktopDC = GetDC(0);

    // Create our memory DC
    HDC hMemDC = CreateCompatibleDC(DesktopDC);
    HBITMAP hBmp = CreateDIB(DesktopDC, lpSize.cx, lpSize.cy, 32);
    if (hBmp) {
        SelectObject(hMemDC, hBmp);

        if (gP.shadow == 0) {
            WCHAR szFile[MAX_PATH] = { 0 };
            Path_Combine(szFile, EXEresource(), L"amiga.png");
            GdipLoadImageFromFile(szFile, gP.shadow);
            if (gP.shadow) { GetImageSize(gP.shadow, imgW, imgH); }
        }

        // Draw the OpenGL scene
        DrawTheScene();
        wglMakeCurrent(gP.gldc, gP.glrc);
        SwapBuffers(gP.gldc);
        DrawAndSetupAlphaChannel(hMemDC, -13, -14);

        if (gP.shadow) {
            if (GdipCreateFromHDC(hMemDC, graphics) == 0) {
                GdipSetInterpolationMode(graphics, 2);
                GdipDrawImageRectRectI(graphics, gP.shadow, 1, 14, imgW, imgH, 0, 0, imgW, imgH, 2, imgAttr, lpCallback, callbackdata);
                GdipDeleteGraphics(graphics);
            }
        }

        // Update the layered window
        bf.BlendOp             = AC_SRC_OVER;
        bf.BlendFlags          = 0;
        bf.AlphaFormat         = AC_SRC_ALPHA; // Use source alpha
        bf.SourceConstantAlpha = 255;
        UpdateLayeredWindow (hWnd, DesktopDC, &lp, &lpSize, hMemDC, &ptSrc, 0, &bf, ULW_ALPHA);

        DeleteObject(hBmp);
        DeleteDC(hMemDC);

        // Move the layered window around the screen
        long PlayIt = 0;
        if (xDir == 0) { xDir = MOVE_STEP; yDir = MOVE_STEP; }
        if (xDir > 0) {
            if (gP.x + FRAME_SizeX - 21 > GetSystemMetrics(SM_CXSCREEN)) { xDir = -xDir; PlayIt = -1; }
        } else {
            if (gP.x < 0) { xDir = -xDir; PlayIt = -1; }
        }
        if (yDir > 0) {
            if (gP.y + FRAME_SizeY - 21 > GetSystemMetrics(SM_CYSCREEN)) { yDir = -yDir; PlayIt = -1; }
        } else {
            if (gP.y < 0) { yDir = -yDir; PlayIt = -1; }
        }
        if (PlayIt) { PlayWav(); }
        gP.x += xDir; gP.y += yDir;
        MoveWindow(hWnd, gP.x, gP.y, FRAME_SizeX, FRAME_SizeY + LOGO_SizeY, 0);

    }
    ReleaseDC(0, DesktopDC);
}

To stop the demo, catch the ball and press the ESCAPE key. Or shut it down from the task bar.

Nostalgia of my eighties! 

...

[Patrice Terrier]

The zip file attached to the first post has been updated, to better show the mixing of an image and 3D OpenGL altogether (see RenderAnimation).