view VisualC.html @ 4139:568c9b3c0167 SDL-1.2

* Added configure option --enable-screensaver, to allow enabling the screensaver by default. * Use XResetScreenSaver() instead of disabling screensaver entirely. Full discussion summary from Erik on the SDL mailing list: Current behaviour ================= SDL changes the user's display power management settings without permission from the user and without telling the user. The interface that it uses to do so is DPMSDisable/DPMSEnable, which should only ever be used by configuration utilities like KControl, never by normal application programs, let alone by the libraries that they use. Using an interface that is not at all intended for what SDL tries to achieve means that it will not work as it should. Firstly, the power management is completely disabled during the whole lifetime of the SDL program, not only when it should be. Secondly, it makes SDL non-reentrant, meaning that things will break when multiple SDL programs are clients of the same X server simultaneously. Thirdly, no cleanup mechanism ensures that the setting is restored if the client does not do that (for example if it crashes). In addition to that, this interface is broken on xorg, [http://bugs.freedesktop.org/show_bug.cgi?id=13962], so what SDL tries to do does not work at all on that implementation of the X Window System. (The reason that the DPMSEnable works in KControl is that it calls DPMSSetTimeout immediately after, [http://websvn.kde.org/tags/KDE/3.5.9/kdebase/kcontrol/energy/energy.cpp?annotate=774532#l343]). The problems that the current behaviour causes ============================================== 1. Information leak. When the user is away, someone might see what the user has on the display when the user counts on the screensaver preventing this. This does not even require physical access to the workstation, it is enough to see it from a distance. 2. Draining battery. An SDL program that runs on a laptop will quickly drain the battery while the user is away. The system will soon shut down and require recharging before being usable again, while it should in fact have consumed very little energy if the user's settings would have been obeyed. 3. Wasting energy. Even if battery issues are not considered, energy as such is wasted. 4. Display wear. The display may be worn out. The problems that the current behaviour tries to solve ====================================================== 1. Preventing screensaver while playing movies. Many SDL applications are media players. They have reasons to prevent screensavers from being activated while a movie is being played. When a user clicks on the play button it can be interpreted as saying "play this movie, but do not turn off the display while playing it, because I will watch it even though I do not interact with the system". 2. Preventing screensaver when some input bypasses X. Sometimes SDL uses input from another source than the X server, so that the X server is bypassed. This obviously breaks the screensaver handling. SDL tries to work around that. 3. Preventing screensaver when all input bypasses X. There is something called Direct Graphics Access mode, where a program takes control of both the display and the input devices from the X server. This obviously means that the X server can not handle the screensaver alone, since screensaver handling depends on input handling. SDL does not do what it should to help the X server to handle the screensaver. Nor does SDL take care of screeensaver handling itself. SDL simply disables the screensaver completely. How the problems should be solved ================================= The correct way for an application program to prevent the screensaver under X is to call XResetScreenSaver. This was recently discovered and implemented by the mplayer developers, [http://svn.mplayerhq.hu/mplayer?view=rev&revision=25637]. SDL needs to wrap this in an API call (SDL_ResetScreenSaver) and implement it for the other video targets (if they do not have a corresponding call, SDL should do what it takes on that particular target, for example sending fake key events). 1. When a movie is played, the player should reset the screensaver when the animation is advanced to a new frame. The same applies to anything similar, like slideshows. 2. When the X server is handling input, it must handle all input (keyboards, mice, gamepads, ...). This is necessary, not only to be able to handle the screensaver, but also so that it can send the events to the correct (the currently active) client. If there is an input device that the X server can not handle for some reason (such as lack of Plug and Play capability), the program that handles the device as a workaround must simulate what would happen if the X server would have handled the device, by calling XResetScreenSaver when input is received from the device. 3. When the X server is not handling the input, it depends on the program that does to call XResetScreenSaver whenever an input event occurs. Alternatively the program must handle the screensaver countdown internally and call XActivateScreenSaver.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 29 Feb 2008 13:55:44 +0000
parents b004c6c24a98
children d63e9f5944ae
line wrap: on
line source

<HTML>
	<HEAD>
		<TITLE>Using SDL with Microsoft Visual C++</TITLE>
	</HEAD>
	<BODY>
		<H1>
			Using SDL with Microsoft Visual C++ 5,6&nbsp;and 7
		</H1>
		<H3>
			by <A HREF="mailto:snowlion@sprynet.com">Lion Kimbro </A>and additions by <A HREF="mailto:james@conceptofzero.net">
				James Turk</A>
		</H3>
		<p>
			You can either use the precompiled libraries from <A HREF="http://www.libsdl.org/download.php">
				the SDL Download web site </A>, or you can build SDL yourself.
		</p>
		<H3>
			Building SDL
		</H3>
		<P>
			Unzip the <CODE>VisualC.zip</CODE> file into the directory that contains this 
			file (<CODE>VisualC.html</CODE>).
		</P>
		<P>
			Be certain that you unzip the zip file for your compiler into <strong>this</strong>
			directory and not any other directory. If you are using WinZip, be careful to 
			make sure that it extracts to <strong>this</strong> folder, because it's 
			convenient feature of unzipping to a folder with the name of the file currently 
			being unzipped will get you in trouble if you use it right now. And that's all 
			I have to say about that.
		</P>
		<P>
			Now that it's unzipped, go into the VisualC 
			directory that is created, and double-click on the VC++ file "<CODE>SDL.dsw</CODE>"<STRONG><FONT color="#009900">
					("<CODE>SDL.sln</CODE>").</FONT></STRONG> This should open up the IDE.
		</P>
		<P>
			You may be prompted at this point to upgrade the workspace, should you be using 
			a more recent version of Visual C++. If so, allow the workspace to be upgraded.
		</P>
		<P>
			Build the <CODE>.dll</CODE> and <CODE>.lib</CODE> files.
		</P>
		<P>
			This is done by right clicking on each project in turn (Projects are listed in 
			the Workspace panel in the FileView tab), and selecting "Build".
		</P>
		<P>
			If you get an error about SDL_config.h being missing, you should
			copy include/SDL_config.h.default to include/SDL_config.h and try again.
		</P>
		<P>
			You may get a few warnings, but you should not get any errors. You do have to 
			have at least the DirectX 5 SDK installed, however. The latest 
			version of DirectX can be downloaded or purchased on a cheap CD (my 
			recommendation) from <A HREF="http://www.microsoft.com">Microsoft </A>.
		</P>
		<P>
			Later, we will refer to the following .lib and .dll files that have just been 
			generated:
		</P>
		<ul>
    <li> SDL.dll</li>
    <li> SDL.lib</li>
    <li> SDLmain.lib</li>
    </ul>
		<P>
			Search for these using the Windows Find (Windows-F) utility, if you don't 
			already know where they should be. For those of you with a clue, look inside 
			the Debug or Release directories of the subdirectories of the Project folder. 
			(It might be easier to just use Windows Find if this sounds confusing. And 
			don't worry about needing a clue; we all need visits from the clue fairy 
			frequently.)
		</P>
		<H3>
			Creating a Project with SDL
		</H3>
		<P>
			Create a project as a Win32 Application.
		</P>
		<P>
			Create a C++ file for your project.
		</P>
		<P>
			Set the C runtime to "Multi-threaded DLL" in the menu: <CODE>Project|Settings|C/C++ 
				tab|Code Generation|Runtime Library </CODE>.
		</P>
		<P>
			Add the SDL <CODE>include</CODE> directory to your list of includes in the 
			menu: <CODE>Project|Settings|C/C++ tab|Preprocessor|Additional include directories </CODE>
			.
			<br>
			<STRONG><FONT color="#009900">VC7 Specific: Instead of doing this I find it easier to 
					add the include and library directories to the list that VC7 keeps. Do this by 
					selecting Tools|Options|Projects|VC++ Directories and under the "Show 
					Directories For:" dropbox select "Include Files", and click the "New Directory 
					Icon" and add the [SDLROOT]\include directory (ex. If you installed to 
					c:\SDL-1.2.5\ add c:\SDL-1.2.5\include).&nbsp;Proceed to&nbsp;change the 
					dropbox selection to "Library Files" and add [SDLROOT]\lib.</FONT></STRONG>
		</P>
			<P>
				The "include directory" I am referring to is the <CODE>include</CODE> folder 
				within the main SDL directory (the one that this HTML file located within).
			</P>
			<P>
				Now we're going to use the files that we had created earlier in the Build SDL 
				step.
			</P>
			<P>
				Copy the following files into your Project directory:
			</P>
			<ul>
     <li> SDL.dll</li>
     </ul>
			<P>
				Add the following files to your project (It is not necessary to copy them to 
				your project directory):
			</P>
			<ul>
     <li> SDL.lib </li>
     <li> SDLmain.lib</li>
     </ul>
			<P>
				(To add them to your project, right click on your project, and select "Add 
				files to project")
			</P>
		<P><STRONG><FONT color="#009900">Instead of adding the files to your project it is more 
					desireable to add them to the linker options: Project|Properties|Linker|Command 
					Line and type the names of the libraries to link with in the "Additional 
					Options:" box.&nbsp; Note: This must be done&nbsp;for&nbsp;each&nbsp;build 
					configuration (eg. Release,Debug).</FONT></STRONG></P>
		<H3>
			SDL 101, First Day of Class
		</H3>
		<P>
			Now create the basic body of your project. The body of your program should take 
			the following form: <CODE>
				<PRE>
#include "SDL.h"

int main( int argc, char* argv[] )
{
  // Body of the program goes here.
  return 0;
}
</PRE>
			</CODE>
		<P></P>
		<H3>
			That's it!
		</H3>
		<P>
			I hope that this document has helped you get through the most difficult part of 
			using the SDL: installing it. Suggestions for improvements to this document 
			should be sent to the writers of this document.
		</P>
		<P>
			Thanks to Paulus Esterhazy (pesterhazy@gmx.net), for the work on VC++ port.
		</P>
		<P>
			This document was originally called "VisualC.txt", and was written by <A HREF="mailto:slouken@libsdl.org">
				Sam Lantinga</A>.
		</P>
		<P>
			Later, it was converted to HTML and expanded into the document that you see 
			today by <A HREF="mailto:snowlion@sprynet.com">Lion Kimbro</A>.
		</P>
		<P>Minor Fixes and Visual C++ 7 Information (In Green) was added by <A HREF="mailto:james@conceptofzero.net">James Turk</A>
		</P>
	</BODY>
</HTML>