TSLAcceleratedRenderControl Class Reference

Inheritance diagram for TSLAcceleratedRenderControl:

Detailed Description

This class provides the interface between the OpenGL Accelerated drawing surface and the TSLAcceleratedRenderer.

The class is abstract to allow the user control on how the map tiles are generated (sequentially, separate thread or process [limitations apply]).

The user may also define their own behaviour by inheriting from this class.

When a tile needs to be rendered the method 'renderTile()' will be called.

The derived 'renderTile()' method will need to call the following methods:

renderer->renderTile(tile); // Draws the tile. renderer->tileRendered(); // Notifies the Accelerated Surface // tile has been rendered. callTileRenderedCallback(); // Call the user's callbacks. callRedrawCallback(numberOfTilesLeftToDraw);

When 'renderTile()' is called ownership of the tile passes to this class (or derived class). It is then the responsibility of this class to return ownership once the tile has been drawn by calling 'tileRendered()'.

Before any tiles are rendered via the TSLAcceleratedRenderer the initialise method must be called. This is particularly important on X11 where we need to open a second connection to the X-Server if we are using a thread method. The derived class TSLAcceleratedMTRenderControl takes this approach internally.

Limitations:

A separate process model can only be implemented if process memory can be shared. This is the model adopted on VxWorks (via pthread library).

On Linux it is possible using the clone method. However this may not be fully supported because MapLink uses pthread's internally (there are use group messages that say this approach is not supported).

On X11 we only support 16 True Colour Visuals. The display connection must be to a local X-Server as must the OpenGL display connection as shared pixmaps are used for creating the Texture Tiles.

Public Member Functions
virtual	~TSLAcceleratedRenderControl ()
virtual void	cancelTiles ()
TSLAcceleratedRenderer *	getRenderer ()
virtual bool	isThreaded () const =0
virtual void	renderTile (TSLTextureTile *tile, TSLAcceleratedRenderer *renderer)=0
virtual void	returnObject (void *object, TSLAcceleratedRenderer *renderer)=0

Protected Member Functions
	TSLAcceleratedRenderControl (TSLAcceleratedRedrawCallback redrawCallback=NULL, void *redrawArg=NULL, TSLTextureTileRenderedCallback tileRenderedCallback=NULL, void *tileRenderedArg=NULL)
void	callTileRenderedCallback (int numberLeft=0)
void	callRedrawCallback ()

Constructor & Destructor Documentation

~TSLAcceleratedRenderControl()

virtual TSLAcceleratedRenderControl::~TSLAcceleratedRenderControl ( )

virtual

Destructor.

NOTE: A user derived class must only return once a thread has exited.

On the thread being deleted all outstanding tiles should be returned by calling tileRendered. If they are not then the tiles will probably be leaked.

TSLAcceleratedRenderControl()

TSLAcceleratedRenderControl::TSLAcceleratedRenderControl ( TSLAcceleratedRedrawCallback redrawCallback = NULL, void * redrawArg = NULL, TSLTextureTileRenderedCallback tileRenderedCallback = NULL, void * tileRenderedArg = NULL )

protected

Constructor for TSLAcceleratedRenderControl.

This class can not be created by the user.

Two classes have been implemented:

TSLAcceleratedBlockingRenderControl TSLAcceleratedMTRenderControl

The user may also derive from this class to implement their own tile rendering behaviour.

Parameters

redrawCallback	User supplied callback which will be called once all the pending tiles have been rendered.
redrawArg	User supplied argument to pass to the callback.
tileRenderedCallback	User supplied callback which will be called after each tile has been rendered. A count of the number of tiles pending is also passed to the user method.
tileRenderedArg	User supplied argument to pass to the callback.
See	Also TSLTextureTileRenderedCallback TSLAcceleratedRedrawTile.

Member Function Documentation

callRedrawCallback()

void TSLAcceleratedRenderControl::callRedrawCallback ( )

protected

Calls the user supplied redraw callback if it is valid.

callTileRenderedCallback()

void TSLAcceleratedRenderControl::callTileRenderedCallback ( int numberLeft = 0 )

protected

Calls the user supplied tile rendered callback if it is valid.

Parameters

numberLeft

the number of tiles left to render.

cancelTiles()

virtual void TSLAcceleratedRenderControl::cancelTiles ( )

virtual

Cancel any pending rendering of tiles.

This method should be overridden in a derived class to supply the expected behaviour.

This method should not be called by any user code.

getRenderer()

TSLAcceleratedRenderer * TSLAcceleratedRenderControl::getRenderer

(

)

Returns a pointer to a specialised TSLAcceleratedRenderer.

If NULL is returned then the renderer has not yet been added.

Once the renderer is available a copy of the pointer can be retained for future reference.

isThreaded()

virtual bool TSLAcceleratedRenderControl::isThreaded ( ) const

pure virtual

This method returns true if the Render Control is multi-threaded.

Implemented in TSLAcceleratedBlockingRenderControl, and TSLAcceleratedMTRenderControl.

renderTile()

virtual void TSLAcceleratedRenderControl::renderTile ( TSLTextureTile * tile, TSLAcceleratedRenderer * renderer )

pure virtual

This method is called by the Accelerated Surface to render a tile.

This method should not be called by any user code.

Implemented in TSLAcceleratedBlockingRenderControl, and TSLAcceleratedMTRenderControl.

returnObject()

virtual void TSLAcceleratedRenderControl::returnObject ( void * object, TSLAcceleratedRenderer * renderer )

pure virtual

This method is called by the Accelerated Surface to return an object to the Render Control cache.

This method should not be called by any user code.

Implemented in TSLAcceleratedBlockingRenderControl, and TSLAcceleratedMTRenderControl.