C++ animate anything correctly

someone 20

I want to understand how to correctly display something in win32.

For example, how to make a square that will move with sin() up and down, so that it is correct and not as I did it through CreateCompatibleDC and create a Bitmap and then move all of it and all this in one thread that was slower to respond with each line of code. Without using wm_paint and wm_timer*

I hope the translator got it right : 3

Darran Rowe 1,321 Reputation points

2024-12-28T14:04:25.03+00:00
There are ways of getting timers that are not see as low priority. The Thread Pool API can be used as one example. The Thread Pool API has the functions CreateThreadpoolTimer, SetThreadpoolTimer and CloseThreadpoolTimer. It is also possible to use the WinRT Thread Pool API. It is highly recommended to use C++/WinRT if the WinRT API is used.

I also find that using the WinRT DispatcherQueue, which can be created in desktop applications using CreateDispatcherQueueController, is nice too. Using the DispatcherQueue allows the use of the DispatcherQueueTimer.

There is also the possibility of using a message pump that is based around PeekMessage instead of GetMessage. This is the kind of message pump that is favoured by games.

int do_message_pump() { bool working{true}; MSG msg{}; while(working) { if(PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE)) { TranslateMessage(&msg); DispatchMessage(&msg); if(msg.message == WM_QUIT) { working = false; } } else { //Do animation work here. } } return static_cast<int>(msg.wParam); }

This kind of message pump allows any time when the thread would be blocked by GetMessage to go into work for the game. But the issue with this kind of message pump is that the main thread will not block.

There is one important point to be made here. None of these techniques are that useful if the drawing routines are slow. If the drawing routines take half a second to draw, then that will give a maximum of 2fps regardless of techniques used. It is possible to move work off of the main thread. This will keep the window more responsive, but it will not magically increase the performance of drawing code.
Roy Li - MSFT 33,586 Reputation points Microsoft Vendor

2025-01-06T07:45:01.5066667+00:00

Haven't heard from you for a while. Have you solved your issue? Does @Castorix31 's answer makes sense?

1 answer

Castorix31 86,481 Reputation points

2024-12-28T13:05:49.12+00:00

For animations, you must use Direct2D (it uses GPU, a lot smoother than GDI/GDI+, using CPU), with a Device Context for recent OS as explained at : https://learn.microsoft.com/en-us/windows/win32/direct2d/devices-and-device-contexts

It seems complicated the 1rst time, but afterwards you just have to copy/paste all same initializations, and the main drawing code is inside BeginDraw/EndDraw.

You can see MS SDK samples like SimplePathAnimationSample or TextAnimationSample at https://github.com/microsoft/Windows-classic-samples/tree/main/Samples/Win7Samples/multimedia/Direct2D

Animation is done "automatically" with InvalidateRect(m_hwnd, NULL, FALSE);

which generates frames at screen refresh rate (60 Hz on my PC)

For a lot of bitmaps, an efficient way is with ID2D1SpriteBatch

(I used sprites in some WinUI 3 / C# test samples (easy to convert into C++)

like WinUI3_SwapChainPanel_Direct2D or WinUI3_Direct2D_Composition )
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C++ animate anything correctly

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