Game development - Revision history

amigadave: /* SDL specific notes */ tidy

amigadave — Tue, 11 May 2010 10:42:20 GMT

SDL specific notes: tidy

← Older revision		Revision as of 10:42, 11 May 2010
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	Things to remember:		Things to remember:
-	* The screen is natively 800x480. No resolution changes are supported. Maybe in the future we might have support for 400x240 res for faster graphics but this is quite unlikely. If trying to set fullscreen window smaller than the native screen size, you will just have black borders.	+	* The screen is natively 800x480 pixels. No resolution changes are supported. Maybe in the future we might have support for 400x240 res for faster graphics but this is quite unlikely. If trying to set a fullscreen window that is smaller than the native screen size, you will just have black borders.
-	* In windowed mode matchbox will force the window to certain size (you should look at the UI specifications to see the actual window size). If your requested window is smaller than this, your window will be aligned to the upper-left and have black borders on the lower-right.	+	* In windowed mode, matchbox will force the window to certain size (you should look at the UI specifications to see the actual window size). If your requested window is smaller than this, your window will be aligned to the upper-left and have black borders on the lower-right. Generally, SDL windows (not fullscreen) look quite bad with the theme, if nothing for the theme is done inside the SDL window, but it's up to you to decide.
-	Generally SDL windows (not fullscreen) look quite bad with the theme if nothing for the theme is done inside the SDL window, but it's up to you to decide.	+	* Avoid full 800x480 screen updates. Memory bandwidth is limited. If you still have to do these for some reason, you should make the area smaller (for example, having some statusbar or any GUI elements which doesn't need to be updated each time). Also do not use <code>SDL_Flip()</code>, since it will update the whole screen. Use rect updating functions instead. Thank you.
-	* Avoid full 800x480 screen updates. Memory bandwidth is limited. If you still have to do these for some reason, you should make the area smaller (eg having some statusbar or any GUI elements which doesn't need to be updated each time). Also do not use SDL_Flip(), since it will update whole screen. Use rect updating functions instead. Thank you.	+	* 32 bit mode doesn't work. The reason was that there was a bug that caused SDL to segfault when you had 32 bit window and you recreated the window. Since the display is only 16 bit, there is no reason to support 32 bit mode, which would just give an extra round of pixel conversion and therefore slow things down. Convert your images on loading to native 16-bit with SDL.
-	* 32 bit mode doesn't work. The reason was that there was a bug that caused SDL to segfault when you had 32 bit window and you recreated the window. Since the display is only 16 bit, there is no reason to support 32 bit mode, which would just give extra round of pixel conversion and therefore slow things down. Convert your images on loading to native 16-bit with SDL.	+	* Mouse events. There is touchscreen, and you cannot assume that an average end user would hack the device to give USB host mode and use the USB mouse. So, use absolute coordinates as much as possible. One example where relative coordinates are used is scummvm. If you use the keypad to move the cursor, and then use the touchscreen, the actuall cursor will be at offset from original touchpadpress. Think absolutely, not relatively ;)
-	* Mouse events. There is touchscreen, and you ~~can't~~ assume average end user ~~Billy-Bob~~ would hack the device to USB host mode and use the USB mouse. So use absolute coordinates as much as possible. One example where relative coordinates are used is scummvm. If you use keypad to move the cursor, and then use the touchscreen, the actuall cursor will be at offset from original touchpadpress. Think absolutely, not relatively ;)	+
-		+

	===Adding support for the Task Navigator===		===Adding support for the Task Navigator===

amigadave: wikify

amigadave — Tue, 11 May 2010 10:38:20 GMT

wikify

← Older revision		Revision as of 10:38, 11 May 2010
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	This page contains tips on game development and SDL library usage for internet tablets.		This page contains tips on game development and SDL library usage for internet tablets.

-	=Useful Tips=	+	==Useful Tips==

-	==Hardware notes==	+	===Hardware notes===

	* Internet tablets use a touchscreen, which enables new ways to implement game-features, such as on-screen buttons, in-game drawing, moving * character by tapping screen. etc.		* Internet tablets use a touchscreen, which enables new ways to implement game-features, such as on-screen buttons, in-game drawing, moving * character by tapping screen. etc.
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	* When using screen's vertical orientation (as in tetris) think other use for esc button than exiting game. It's so close to the rocker that accidental presses will happen.		* When using screen's vertical orientation (as in tetris) think other use for esc button than exiting game. It's so close to the rocker that accidental presses will happen.

-	==SDL specific notes==	+	===SDL specific notes===

	Things to remember:		Things to remember:
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-	==Adding support for the Task Navigator==	+	===Adding support for the Task Navigator===

-	===Create an entry in the task list===	+	====Create an entry in the task list====

	The Maemo Task Navigator identifies non-Maemo programs (like pure SDL applications) by matching the <code>StartupWMClass</code>-variable in the <code>.desktop</code>-file and the application "window manager class" name. By default all SDL applications have the name <code>SDL_App</code>. This can be changed with the environment variable <code>SDL_VIDEO_X11_WMCLASS</code>.		The Maemo Task Navigator identifies non-Maemo programs (like pure SDL applications) by matching the <code>StartupWMClass</code>-variable in the <code>.desktop</code>-file and the application "window manager class" name. By default all SDL applications have the name <code>SDL_App</code>. This can be changed with the environment variable <code>SDL_VIDEO_X11_WMCLASS</code>.
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	* Alternative 1: Here <code>app.bin</code> is the binary executable and <code>app</code> is a wrapper script:		* Alternative 1: Here <code>app.bin</code> is the binary executable and <code>app</code> is a wrapper script:

-	<~~pre~~>	+	<source lang="bash">
	#!/bin/sh		#!/bin/sh
	BASENAME=`basename $0`		BASENAME=`basename $0`
	export SDL_VIDEO_X11_WMCLASS=${BASENAME}		export SDL_VIDEO_X11_WMCLASS=${BASENAME}
	exec ${0}.bin "$@"		exec ${0}.bin "$@"
-	</~~pre~~>	+	</source>

	Notice that <code>StartupWMClass == SDL_VIDEO_X11_WMCLASS</code>, and that <code>Exec</code> points to the wrapper script, not the main program.		Notice that <code>StartupWMClass == SDL_VIDEO_X11_WMCLASS</code>, and that <code>Exec</code> points to the wrapper script, not the main program.
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	* Alternative 2: An other possibility that doesn't need a script is the following. Put the line		* Alternative 2: An other possibility that doesn't need a script is the following. Put the line

-	<~~pre~~>	+	<source lang="c">
	putenv("SDL_VIDEO_X11_WMCLASS=app");		putenv("SDL_VIDEO_X11_WMCLASS=app");
-	</~~pre~~>	+	</source>

	in your code. A good position is directly at the beginning of the <code>main</code> method. This way there is no need for a helper script.		in your code. A good position is directly at the beginning of the <code>main</code> method. This way there is no need for a helper script.

-	===Set the window title===	+	====Set the window title====

	If you see "unknown" title in task list (OS2008 bug/feature), you can set it by using:		If you see "unknown" title in task list (OS2008 bug/feature), you can set it by using:

-	<~~pre~~>	+	<source lang="c">
	#include <SDL/SDL_syswm.h>		#include <SDL/SDL_syswm.h>
	#include <X11/Xutil.h>		#include <X11/Xutil.h>
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	if (dpy && win) XStoreName(dpy, win, "Title");		if (dpy && win) XStoreName(dpy, win, "Title");
	}		}
-	</~~pre~~>	+	</source>
		+
	Alternatively you can try to set title for both windows no matter if fullscreen or not. This seems to work and saves you setting the title again after fullscreen switch.		Alternatively you can try to set title for both windows no matter if fullscreen or not. This seems to work and saves you setting the title again after fullscreen switch.
-	<~~pre~~>	+
		+	<source lang="c">
	Display *dpy = info.info.x11.display;		Display *dpy = info.info.x11.display;
	Window win;		Window win;
Line 93:		Line 95:
	if (win) XStoreName(dpy, win, "Title");		if (win) XStoreName(dpy, win, "Title");
	}		}
-	</~~pre~~>	+	</source>

-	If SDL_WM_SetCaption is present in the code, add the code above after that call. Or, just remove SDL_WM_SetCaption as the code above will set the window title and the icon for the window is handled by hildon-desktop using the Icon field in your desktop file.	+	If <code>SDL_WM_SetCaption</code> is present in the code, add the code above after that call. Or, just remove <code>SDL_WM_SetCaption</code> as the code above will set the window title and the icon for the window is handled by hildon-desktop using the Icon field in your desktop file.

	If you wish for text to appear in the task navigator on the second line corresponding to your game; make "Title" be: "'text to display on first line' - 'text to display on second line'". The " - " (with spaces) are important.		If you wish for text to appear in the task navigator on the second line corresponding to your game; make "Title" be: "'text to display on first line' - 'text to display on second line'". The " - " (with spaces) are important.

-	==Utilizing pixel doubling inside SDL==	+	===Utilizing pixel doubling inside SDL===

	As there is support for pixel-doubled drawing to the screen inside the HW, there is implementations to utilize that up to X. So if you want to use it you have to do some xlib code, therefore it might be a good idea to put this small piece of code to switch pixel doubling mode to a separate file.		As there is support for pixel-doubled drawing to the screen inside the HW, there is implementations to utilize that up to X. So if you want to use it you have to do some xlib code, therefore it might be a good idea to put this small piece of code to switch pixel doubling mode to a separate file.

-	'''NOTE:''' There is no Xsp scaling on N900 anymore. You might want to use Hildon Animation Actor to scale the pixmap. Either with [http://git.maemo.org/git/sdlhildon/?p=sdlhildon;a=tree;f=sdlhaa SDL_haa] or [~~http://wiki.maemo.org/~~Documentation/Maemo_5_Developer_Guide/Porting_Software/Scaling_Fixed_Size_Windows directly].	+	'''NOTE:''' There is no Xsp scaling on [[Nokia N900\|N900]] anymore. You might want to use Hildon Animation Actor to scale the pixmap. Either with [http://git.maemo.org/git/sdlhildon/?p=sdlhildon;a=tree;f=sdlhaa SDL_haa] or [[Documentation/Maemo_5_Developer_Guide/Porting_Software/Scaling_Fixed_Size_Windows\|directly]].
		+
	====What is pixel doubling?====		====What is pixel doubling?====

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	There exists one X extension (Xsp), which can be used for that. Sample piece of code with SDL:		There exists one X extension (Xsp), which can be used for that. Sample piece of code with SDL:

-	<~~pre~~>	+	<source lang="c">
	#include <X11/Xlib.h>		#include <X11/Xlib.h>
	#include <X11/extensions/Xsp.h>		#include <X11/extensions/Xsp.h>
Line 136:		Line 139:
	XSPSetPixelDoubling(wminfo.info.x11.display, 0, enable);		XSPSetPixelDoubling(wminfo.info.x11.display, 0, enable);
	}		}
-	</~~pre~~>	+	</source>

	Note that when you compile it you have to include X include path and link this with libXsp (-lXsp).		Note that when you compile it you have to include X include path and link this with libXsp (-lXsp).

-	=External Links=	+	==External Links==
-		+
-	~~[http://www.libsdl.org/ Simple DirectMedia Layer Homepage]~~	+

-	[http://www.gamedev.net/ Game Development Resources]	+	* [http://www.libsdl.org/ Simple DirectMedia Layer Homepage]
		+	* [http://www.gamedev.net/ Game Development Resources]

	[[Category:Development]]		[[Category:Development]]
	[[Category:Games]]		[[Category:Games]]

217.17.35.154: Using HAA on N900

217.17.35.154 — Mon, 29 Mar 2010 15:24:57 GMT

Using HAA on N900

← Older revision		Revision as of 15:24, 29 March 2010
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	As there is support for pixel-doubled drawing to the screen inside the HW, there is implementations to utilize that up to X. So if you want to use it you have to do some xlib code, therefore it might be a good idea to put this small piece of code to switch pixel doubling mode to a separate file.		As there is support for pixel-doubled drawing to the screen inside the HW, there is implementations to utilize that up to X. So if you want to use it you have to do some xlib code, therefore it might be a good idea to put this small piece of code to switch pixel doubling mode to a separate file.

		+	'''NOTE:''' There is no Xsp scaling on N900 anymore. You might want to use Hildon Animation Actor to scale the pixmap. Either with [http://git.maemo.org/git/sdlhildon/?p=sdlhildon;a=tree;f=sdlhaa SDL_haa] or [http://wiki.maemo.org/Documentation/Maemo_5_Developer_Guide/Porting_Software/Scaling_Fixed_Size_Windows directly].
	====What is pixel doubling?====		====What is pixel doubling?====

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	Note that when you compile it you have to include X include path and link this with libXsp (-lXsp).		Note that when you compile it you have to include X include path and link this with libXsp (-lXsp).
-

	=External Links=		=External Links=

amigadave: no longer merely a midgard wiki page

amigadave — Thu, 11 Feb 2010 14:36:23 GMT

no longer merely a midgard wiki page

← Older revision		Revision as of 14:36, 11 February 2010
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-	~~[[Category:Games]]~~
-	~~{{Midgard article}}~~
-
	This page contains tips on game development and SDL library usage for internet tablets.		This page contains tips on game development and SDL library usage for internet tablets.

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	[[Category:Development]]		[[Category:Development]]
-	[[Category:~~Midgard wiki~~]]	+	[[Category:Games]]

hypoxic at 04:34, 19 January 2010

hypoxic — Tue, 19 Jan 2010 04:34:35 GMT

← Older revision		Revision as of 04:34, 19 January 2010
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		+	[[Category:Games]]
	{{Midgard article}}		{{Midgard article}}

fanoush: /* Set the window title */

fanoush — Thu, 30 Apr 2009 08:37:50 GMT

Set the window title

← Older revision		Revision as of 08:37, 30 April 2009
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	===Set the window title===		===Set the window title===

-	~~You can set the~~ title ~~shown~~ in ~~the~~ task list by using:	+	If you see "unknown" title in task list (OS2008 bug/feature), you can set it by using:

	<pre>		<pre>

fanoush: /* Set the window title */ you can try to set title for both windows no matter if fullscreen or not

fanoush — Thu, 30 Apr 2009 08:31:42 GMT

Set the window title: you can try to set title for both windows no matter if fullscreen or not

← Older revision		Revision as of 08:31, 30 April 2009
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	if (dpy && win) XStoreName(dpy, win, "Title");		if (dpy && win) XStoreName(dpy, win, "Title");
	}		}
		+	</pre>
		+	Alternatively you can try to set title for both windows no matter if fullscreen or not. This seems to work and saves you setting the title again after fullscreen switch.
		+	<pre>
		+	Display *dpy = info.info.x11.display;
		+	Window win;
		+	if (dpy){
		+	win = info.info.x11.fswindow;
		+	if (win) XStoreName(dpy, win, "Title");
		+	win = info.info.x11.wmwindow;
		+	if (win) XStoreName(dpy, win, "Title");
		+	}
	</pre>		</pre>

qwerty12: add description on how to display text on second line

qwerty12 — Wed, 29 Apr 2009 23:02:53 GMT

add description on how to display text on second line

← Older revision		Revision as of 23:02, 29 April 2009
Line 87:		Line 87:

	If SDL_WM_SetCaption is present in the code, add the code above after that call. Or, just remove SDL_WM_SetCaption as the code above will set the window title and the icon for the window is handled by hildon-desktop using the Icon field in your desktop file.		If SDL_WM_SetCaption is present in the code, add the code above after that call. Or, just remove SDL_WM_SetCaption as the code above will set the window title and the icon for the window is handled by hildon-desktop using the Icon field in your desktop file.
		+
		+	If you wish for text to appear in the task navigator on the second line corresponding to your game; make "Title" be: "'text to display on first line' - 'text to display on second line'". The " - " (with spaces) are important.

	==Utilizing pixel doubling inside SDL==		==Utilizing pixel doubling inside SDL==

qwerty12: Add wmcaption note

qwerty12 — Wed, 29 Apr 2009 22:11:48 GMT

Add wmcaption note

← Older revision		Revision as of 22:11, 29 April 2009
Line 85:		Line 85:
	}		}
	</pre>		</pre>
		+
		+	If SDL_WM_SetCaption is present in the code, add the code above after that call. Or, just remove SDL_WM_SetCaption as the code above will set the window title and the icon for the window is handled by hildon-desktop using the Icon field in your desktop file.

	==Utilizing pixel doubling inside SDL==		==Utilizing pixel doubling inside SDL==

qwerty12: Sorry, remove false set wmcaption 'hint'

qwerty12 — Wed, 29 Apr 2009 21:59:10 GMT

Sorry, remove false set wmcaption 'hint'

← Older revision		Revision as of 21:59, 29 April 2009
Line 84:		Line 84:
	if (dpy && win) XStoreName(dpy, win, "Title");		if (dpy && win) XStoreName(dpy, win, "Title");
	}		}
-	~~</pre>~~
-
-	~~To set the title shown in the titlebar at the top (for a non-fullscreen SDL program) use (the code above is still needed to see it in the task list):~~
-	~~<pre>~~
-	~~SDL_WM_SetCaption("title", NULL);~~
	</pre>		</pre>