KDE Games/Porting

Targets of porting

• Graphics stack: QGraphicsView is currently the recommended solution. Some games still use KGameCanvas; these should be ported to QGraphicsView. In the future, we likely want to move to Qt Quick instead, but this needs proper investigation and changes in libkdegames.
• Rendering method: Current solutions commonly include usage of a QSvgRenderer, combined either with QGraphicsSvgItems or with (Q/K)PixmapCache. It is suggested to migrate to KGameRenderer instead. Integration with QGraphicsView is available through the KGameRenderedItem and KGameRenderedObjectItem classes. Integration with KGameCanvas is available through the KGameCanvasRenderedPixmap.
• Theme selection: When one game supports multiple themes, the KGameTheme class has commonly been used. Starting with the 4.9 release, the new KgTheme class supersedes KGameTheme.
• Sounds: Some games used Phonon, some KNotify. Both libraries are bad because of their commonly high playback latencies. The new KgSound classes in libkdegames are specialized on low-latency playback of small sound samples.
• (more to come)

Porting status

This table explains the usage of relevant libraries and highlights those parts of the code which need porting. "N/A" means "not applicable", that is: This application does not use this specific type of library functionality at all (e.g. it does not play any sounds). When the "Sounds" column says "none", there is no code that plays sounds (like "N/A"), but there are sound files in the source tree, so the application should (probably?) be playing sounds.

If you want to take part in porting, pick an app, contact the author or the kde-games-devel mailing list to coordinate your effort, read into the API documentation and start hacking! Please note that the complexity of ports (roughly) increases from right to left. Porting to KgSound is largely unproblematic, while porting from KGameCanvas to QGraphicsView is a very deep cut that likely introduces subtle errors if not executed properly.

Warning: When porting to KGameRenderer, it is advised not to use the primaryView property of KGameRenderedObjectItem class in new ports. The existing ports using it (KDiamond and Klickety/KSame) made it clear that the primaryView property has design flaws (concerning performance), so it will probably be removed again.

Application	Graphics stack	Rendering method	Theme selection	Sounds
bomber	QGraphicsView	KGameRenderer	KgTheme	Phonon
bovo	QGraphicsView	QGraphicsSvgItem	N/A	N/A
granatier	QGraphicsView	KGameRenderer	KgTheme+custom	KgSound
kajongg	QGraphicsView	libkmahjongg	N/A	custom
kapman	QGraphicsView	QGraphicsSvgItem	KGameTheme	KgSound
katomic	QGraphicsView	KGameRenderer	KgTheme	N/A
kbattleship (see knavalbattle)
kblackbox	QGraphicsView	QGraphicsSvgItem	N/A	N/A
kblocks	QGraphicsView	QGraphicsSvgItem	KGameTheme	Phonon
kbounce	QGraphicsView	KGameRenderer	N/A	KgSound
kbreakout	QtQuick	KGameRenderer	KgTheme	none
kdiamond	QGraphicsView	KGameRenderer	KgTheme	KNotify
kfourinline	QGraphicsView	PixmapCache (client pattern)	N/A	N/A
kgoldrunner	KGameCanvas	KPixmapCache	N/A	KgSound
kigo	QGraphicsView	KPixmapCache	KGameTheme	N/A
killbots	QGraphicsView	KGameRenderer	KgTheme	N/A
kiriki	QWidget with pre-rendered PNG		N/A	N/A
kjumpingcube	QWidget	QSvgRenderer	N/A	N/A
klickety	QGraphicsView	KGameRenderer	KgTheme	KNotify
klines	QGraphicsView	KPixmapCache	N/A	N/A
kmahjongg	KGameCanvas	libkmahjongg	N/A	N/A
kmines	QGraphicsView	KGameRenderer	KgTheme	N/A
knavalbattle	KGameCanvas	QSvgRenderer, QHash	N/A	Phonon
knetwalk	QGraphicsView	KGameRenderer	KgTheme	KNotify
kolf	QGraphicsView	KGameRenderer	KgTheme	Phonon
kollision	QGraphicsView	KGameRenderer	KgTheme	KgSound
konquest	QGraphicsView	KPixmapCache	N/A	N/A
kpat	QGraphicsView	KGameRenderer	KgTheme+KCardTheme	KgSound
kreversi	QGraphicsView	KGameRenderer	KgTheme	none
kshisen	QWidget	libkmahjongg	N/A	KgSound
ksirk	QGraphicsView	QGraphicsSvgItem+KPixmapCache	N/A	Phonon
kspaceduel	QGraphicsView	QGraphicsSvgItem	N/A	N/A
ksquares	QGraphicsView	N/A	N/A	N/A
ksudoku	QGraphicsView	KPixmapCache	KGameTheme	N/A
ktron	QWidget	KPixmapCache	KGameTheme	N/A
ktuberling	QGraphicsView	QGraphicsSvgItem	N/A	Phonon
kubrick	QGLWidget	N/A	N/A	N/A
libkmahjongg	N/A	QPixmapCache	N/A	N/A
lskat	QGraphicsView	PixmapCache (client pattern)	N/A	none
palapeli	QGraphicsView	N/A	N/A	N/A