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Public Types | Public Member Functions | Protected Member Functions | Protected Attributes

OSystem_POSIX Class Reference

Inheritance diagram for OSystem_POSIX:
Inheritance graph
Collaboration diagram for OSystem_POSIX:
Collaboration graph

List of all members.

Public Types

enum  SdlEvent { kSdlEventExpose = 100, kSdlEventResize = 101 }
Feature flags
enum  Feature {
  kFeatureFullscreenMode, kFeatureAspectRatioCorrection, kFeatureVirtualKeyboard, kFeatureCursorHasPalette,
  kFeatureOverlaySupportsAlpha, kFeatureIconifyWindow, kFeatureDisableKeyFiltering
Mutex handling

Historically, the OSystem API used to have a method which allowed creating threads. Hence mutex support was needed for thread syncing. To ease portability, though, we decided to remove the threading API. Instead, we now use timers (see setTimerCallback() and Common::Timer). But since those may be implemented using threads (and in fact, that's how our primary backend, the SDL one, does it on many systems), we still have to do mutex syncing in our timer callbacks. In addition, the sound mixer uses a mutex in case the backend runs it from a dedicated thread (as e.g. the SDL backend does).

Hence backends which do not use threads to implement the timers simply can use dummy implementations for these methods.

typedef struct OpaqueMutex * MutexRef

Public Member Functions

virtual void addSysArchivesToSearchSet (Common::SearchSet &s, int priority=0)
createConfigReadStream ()
virtual Common::WriteStreamcreateConfigWriteStream ()
virtual void delayMillis (uint msecs)
virtual void engineDone ()
virtual void engineInit ()
virtual void fatalError ()
virtual Common::HardwareKeySet * getHardwareKeySet ()
virtual uint32 getMillis ()
virtual Audio::MixergetMixer ()
virtual SdlMixerManagergetMixerManager ()
virtual Common::String getSystemLanguage () const
virtual void getTimeAndDate (TimeDate &td) const
virtual void init ()
virtual void initBackend ()
virtual void logMessage (LogMessageType::Type type, const char *message)
 OSystem_POSIX (Common::String baseConfigName=".scummvmrc")
virtual void quit ()
virtual void setWindowCaption (const char *caption)
virtual bool hasFeature (Feature f)
virtual void setFeatureState (Feature f, bool enable)
virtual bool getFeatureState (Feature f)
virtual GraphicsManagergetGraphicsManager ()
virtual const GraphicsModegetSupportedGraphicsModes () const
virtual int getDefaultGraphicsMode () const
virtual bool setGraphicsMode (int mode)
virtual int getGraphicsMode () const
virtual void resetGraphicsScale ()
virtual void initSize (uint width, uint height, const Graphics::PixelFormat *format=NULL)
virtual int getScreenChangeID () const
virtual void beginGFXTransaction ()
virtual OSystem::TransactionError endGFXTransaction ()
virtual int16 getHeight ()
virtual int16 getWidth ()
virtual PaletteManagergetPaletteManager ()
virtual void copyRectToScreen (const byte *buf, int pitch, int x, int y, int w, int h)
virtual Graphics::SurfacelockScreen ()
virtual void unlockScreen ()
virtual void fillScreen (uint32 col)
virtual void updateScreen ()
virtual void setShakePos (int shakeOffset)
virtual void setFocusRectangle (const Common::Rect &rect)
virtual void clearFocusRectangle ()
virtual void showOverlay ()
virtual void hideOverlay ()
virtual Graphics::PixelFormat getOverlayFormat () const
virtual void clearOverlay ()
virtual void grabOverlay (OverlayColor *buf, int pitch)
virtual void copyRectToOverlay (const OverlayColor *buf, int pitch, int x, int y, int w, int h)
virtual int16 getOverlayHeight ()
virtual int16 getOverlayWidth ()
virtual bool showMouse (bool visible)
virtual void warpMouse (int x, int y)
virtual void setMouseCursor (const byte *buf, uint w, uint h, int hotspotX, int hotspotY, uint32 keycolor, int cursorTargetScale=1, const Graphics::PixelFormat *format=NULL)
virtual void setCursorPalette (const byte *colors, uint start, uint num)
virtual void disableCursorPalette (bool disable)
Events and Time
virtual Common::TimerManagergetTimerManager ()
virtual Common::EventManagergetEventManager ()
Mutex handling
virtual MutexRef createMutex ()
virtual void lockMutex (MutexRef mutex)
virtual void unlockMutex (MutexRef mutex)
virtual void deleteMutex (MutexRef mutex)
Audio CD
virtual AudioCDManagergetAudioCDManager ()
virtual Common::SaveFileManagergetSavefileManager ()
virtual FilesystemFactorygetFilesystemFactory ()
virtual void displayMessageOnOSD (const char *msg)

Protected Member Functions

virtual Common::WriteStreamcreateLogFile ()
virtual Common::String getDefaultConfigFileName ()
virtual void initSDL ()
virtual void setupIcon ()

Protected Attributes

Common::String _baseConfigName
bool _inited
bool _initedSDL
Managers variables


The way graphics work in the class OSystem are meant to make it possible for game frontends to implement all they need in an efficient manner. The downside of this is that it may be rather complicated for backend authors to fully understand and implement the semantics of the OSystem interface.

The graphics visible to the user in the end are actually composed in three layers: the game graphics, the overlay graphics, and the mouse.

First, there are the game graphics. The methods in this section deal with them exclusively. In particular, the size of the game graphics is defined by a call to initSize(), and copyRectToScreen() blits the data in the current pixel format into the game layer. Let W and H denote the width and height of the game graphics.

Before the user sees these graphics, the backend may apply some transformations to it; for example, the may be scaled to better fit on the visible screen; or aspect ratio correction may be performed (see kFeatureAspectRatioCorrection). As a result of this, a pixel of the game graphics may occupy a region bigger than a single pixel on the screen. We define p_w and p_h to be the width resp. height of a game pixel on the screen.

In addition, there is a vertical "shake offset" (as defined by setShakePos) which is used in some games to provide a shaking effect. Note that shaking is applied to all three layers, i.e. also to the overlay and the mouse. We denote the shake offset by S.

Putting this together, a pixel (x,y) of the game graphics is transformed to a rectangle of height p_h and width p_w appearing at position (p_w * x, p_hw * (y + S)) on the real screen (in addition, a backend may choose to offset everything, e.g. to center the graphics on the screen).

The next layer is the overlay. It is composed over the game graphics. By default, it has exactly the same size and resolution as the game graphics. However, client code can specify an overlay scale (as an additional parameter to initSize()). This is meant to increase the resolution of the overlay while keeping its size the same as that of the game graphics. For example, if the overlay scale is 2, and the game graphics have a resolution of 320x200; then the overlay shall have a resolution of 640x400, but it still has the same physical size as the game graphics. The overlay usually uses 16bpp, but on some ports, only 8bpp are availble, so that is supported, too, via a compile time switch (see also the OverlayColor typedef in scummsys.h).

Finally, there is the mouse layer. This layer doesn't have to actually exist within the backend -- it all depends on how a backend chooses to implement mouse cursors, but in the default SDL backend, it really is a separate layer. The mouse can have a palette of its own, if the backend supports it. The scale of the mouse cursor is called 'cursorTargetScale'. This is meant as a hint to the backend. For example, let us assume the overlay is not visible, and the game graphics are displayed using a 2x scaler. If a mouse cursor with a cursorTargetScale of 1 is set, then it should be scaled by factor 2x, too, just like the game graphics. But if it has a cursorTargetScale of 2, then it shouldn't be scaled again by the game graphics scaler.

bool setGraphicsMode (const char *name)
Graphics::PixelFormat getScreenFormat () const
< Graphics::PixelFormat
getSupportedFormats () const
enum  TransactionError {
  kTransactionSuccess = 0, kTransactionAspectRatioFailed = (1 << 0), kTransactionFullscreenFailed = (1 << 1), kTransactionModeSwitchFailed = (1 << 2),
  kTransactionSizeChangeFailed = (1 << 3), kTransactionFormatNotSupported = (1 << 4)

Detailed Description

Definition at line 31 of file posix.h.

The documentation for this class was generated from the following file:

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