proland::ReadbackManager Class Reference
[terrain]

A manager for asynchronous readbacks from a framebuffer. More...

#include <ReadbackManager.h>

List of all members.

Classes
class	Callback
	A callback function called when a readback is done; see ReadbackManager. More...
Public Member Functions
	ReadbackManager (int maxReadbackPerFrame, int readbackDelay, int bufferSize)
	Creates a new readback manager.
virtual	~ReadbackManager ()
	Destroys this readback manager.
bool	canReadback ()
	Returns true if a new readback can be started for the current frame.
bool	readback (ptr< FrameBuffer > fb, int x, int y, int w, int h, TextureFormat f, PixelType t, ptr< Callback > cb)
	Starts a new readback and returns immediately.
void	newFrame ()
	Informs this manager that a new frame has started.

---

Detailed Description

A manager for asynchronous readbacks from a framebuffer.

Asynchronous means that readbacks are non blocking: a read operation returns immediately with an empty result, and the actual result is passed via a callback function when it becomes available (in practice n frames after the read was started, where n is user defined).

Authors:

Eric Bruneton, Antoine Begault

---

Constructor & Destructor Documentation

proland::ReadbackManager::ReadbackManager	(	int	maxReadbackPerFrame,
		int	readbackDelay,
		int	bufferSize
	)

Creates a new readback manager.

Parameters:

	maxReadbackPerFrame	maximum number of readbacks that can be started per frame.
	readbackDelay	number of frames between the start of a readback and its end.
	bufferSize	maximum number of bytes per readback.

virtual proland::ReadbackManager::~ReadbackManager

(

)

[virtual]

Destroys this readback manager.

---

Member Function Documentation

bool proland::ReadbackManager::canReadback

(

)

Returns true if a new readback can be started for the current frame.

void proland::ReadbackManager::newFrame

(

)

Informs this manager that a new frame has started.

bool proland::ReadbackManager::readback	(	ptr< FrameBuffer >	fb,
		int	x,
		int	y,
		int	w,
		int	h,
		TextureFormat	f,
		PixelType	t,
		ptr< Callback >	cb
	)

Starts a new readback and returns immediately.

Returns true if the readback has effectively started (see canReadback()).

Parameters:

	fb	the framebuffer from which the data must be read. Data will be read from the last buffer specified with FrameBuffer::setReadBuffer for this framebuffer.
	x	x coordinate of the lower left corner of the region to be read.
	y	x coordinate of the lower left corner of the region to be read.
	w	width of the region to be read.
	h	height the region to be read.
	f	the components to be read.
	t	the type to be used to store the read data.
	cb	the function to be called when the readback is finished.