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Fixed bug #750 Since many different event structures include windowID it should be placed near the beginning of the structure (preferably right after type) so it's position is the same between different events. This is to avoid code like this: if (event.type == SDL_WINDOWEVENT) win = event.window.windowID; else if ((SDL_EVENTMASK(event.type) & SDL_KEYEVENTMASK) != 0) win = event.key.windowID; else if (event.type == SDL_TEXTINPUT) win = event.text.windowID; else if (event.type == SDL_MOUSEMOTION) win = event.motion.windowID; else if ((SDL_EVENTMASK(event.type) & (SDL_MOUBUTTONDOWNMASK | SDL_MOUBUTTONUPMASK)) != 0) win = event.button.windowID; else if (event.type == SDL_MOUSEWHEEL) win = event.wheel.windowID; ... in favor of: win = event.window.windowID;
author Sam Lantinga <slouken@libsdl.org>
date Wed, 10 Jun 2009 14:00:21 +0000
parents 355632dca928
children
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<HTML
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>Events</TITLE
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>Chapter 8. Events</H1
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>Table of Contents</B
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><DT
><A
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>Introduction</A
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><DT
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>SDL Event Structures.</A
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>Event Functions.</A
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>Introduction</H1
><P
>Event handling allows your application to receive input from the user. Event handling is initalised (along with video) with a call to:
<PRE
CLASS="PROGRAMLISTING"
>SDL_Init(SDL_INIT_VIDEO);</PRE
>
Internally, SDL stores all the events waiting to be handled in an event queue. Using functions like <A
HREF="sdlpollevent.html"
><TT
CLASS="FUNCTION"
>SDL_PollEvent</TT
></A
> and <A
HREF="sdlpeepevents.html"
><TT
CLASS="FUNCTION"
>SDL_PeepEvents</TT
></A
> you can observe and handle waiting input events.</P
><P
>The key to event handling in SDL is the <A
HREF="sdlevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
></A
> union. The event queue itself is composed of a series of <SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
> unions, one for each waiting event. <SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
> unions are read from the queue with the <TT
CLASS="FUNCTION"
>SDL_PollEvent</TT
> function and it is then up to the application to process the information stored with them.</P
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