makVrv::DtGlBuffer Class Reference

A generic OpenGL buffer. More...

Public Member Functions
	DtGlBuffer (const char *name, DtBufferType type, int sizeInBytes, DtUsage usage, DtCpuAccess accessType, bool hasStagingBuffer, const GLvoid *data=0)
	CTOR.
virtual	~DtGlBuffer ()
	DTOR.
virtual void	resizeBuffer (int sizeInBytes, const GLvoid *data)
	Resize the buffer so that the GPU know about a resize instead of deleting and recreating the buffer.
int	sizeInBytes (void) const
	The size in bytes of the buffer.
GLenum	type (void) const
	The internal OpenGL type of the buffer of the gl buffer.
void	bufferSubData (GLuint offset, GLuint sizeInBytes, const GLvoid *data)
	Optional API to upload data directly to the buffer, side stepping the staging buffer.
GLuint	handle (void) const
	The internal GL handle of the buffer.
void	tearDown (void) const
void	bind ()
	bind/unbind the buffer
void	unbind ()
void	bind (GLenum type)
	Bind/Unbind the buffer.
void	unbind (GLenum type)
GLubyte *	findStagingBuffer (void) const
	Internally GLBuffer uses a 'staging buffer' This is because map/unmap and directly uploading to the buffer is horribly slow in OpenGL.
void	syncToGpu (GLuint offset, GLuint sizeInBytes)
	Use when you modified (and hence need to update) only part of the buffer [offset, offset+sizeInBytes].
void	syncToGpu ()
	Use when you modified (and hence need to update) the whole buffer [0, sizeInBytes()].

Static Public Member Functions
static bool	resizeBufferIfNecessary (DtGlBuffer *&buffer, const char *name, DtBufferType bufferType, int sizeInBytesNeeded, DtUsage usage, DtCpuAccess accessType, bool hasStaging, const void *data)
	Resize the buffer, only if necessary If buffer is null, will create a DtGlBuffer with the requested type and size If buffer is not null and requested size is < its actual size it will resize the buffer to be the requested size.

Protected Attributes
std::string	myName
GLuint	myHandle
GLenum	myType
int	mySizeInBytes
GLubyte *	myStagingBufffer
bool	myHasStagingBuffer
DtUsage	myUsage
DtCpuAccess	myAccessType

Detailed Description

A generic OpenGL buffer.

This can be: -> a vertex buffer -> an index buffer -> a shader storage buffer (SSBO), etc

Constructor & Destructor Documentation

makVrv::DtGlBuffer::DtGlBuffer	(	const char *	name,
		DtBufferType	type,
		int	sizeInBytes,
		DtUsage	usage,
		DtCpuAccess	accessType,
		bool	hasStagingBuffer,
		const GLvoid *	data = 0
	)

CTOR.

Parameters

type	Indicates the type of the buffer this will be (vertex buffer, index buffer, etc)
sizeInBytes	Requested size in bytes
usage	Indicates what the intended usage of this buffer will be (dynamic, const, etc)
accessType	Indicates what level of CPU access is needed (will CPU only ever write, etc)
hasStagingBuffer	indicates whether this buffer will have an internal staging buffer
data	is the (optional) initial data

virtual makVrv::DtGlBuffer::~DtGlBuffer ( )

virtual

DTOR.

Member Function Documentation

virtual void makVrv::DtGlBuffer::resizeBuffer ( int  sizeInBytes, const GLvoid *  data  )

virtual

Resize the buffer so that the GPU know about a resize instead of deleting and recreating the buffer.

void makVrv::DtGlBuffer::bind

(

)

bind/unbind the buffer

void makVrv::DtGlBuffer::unbind

(

)

void makVrv::DtGlBuffer::bind

(

GLenum

type

)

Bind/Unbind the buffer.

A buffer created as one type can be bound/interpreted as a completely different type by OpenGL

void makVrv::DtGlBuffer::unbind

(

GLenum

type

)

int makVrv::DtGlBuffer::sizeInBytes

(

void

)

const

The size in bytes of the buffer.

GLenum makVrv::DtGlBuffer::type

(

void

)

const

The internal OpenGL type of the buffer of the gl buffer.

GLubyte* makVrv::DtGlBuffer::findStagingBuffer

(

void

)

const

Internally GLBuffer uses a 'staging buffer' This is because map/unmap and directly uploading to the buffer is horribly slow in OpenGL.

The usage therefore is to get the staging buffer, modify it and then call syncToGPU

void makVrv::DtGlBuffer::syncToGpu	(	GLuint	offset,
		GLuint	sizeInBytes
	)

Use when you modified (and hence need to update) only part of the buffer [offset, offset+sizeInBytes].

void makVrv::DtGlBuffer::syncToGpu

(

)

Use when you modified (and hence need to update) the whole buffer [0, sizeInBytes()].

void makVrv::DtGlBuffer::bufferSubData	(	GLuint	offset,
		GLuint	sizeInBytes,
		const GLvoid *	data
	)

Optional API to upload data directly to the buffer, side stepping the staging buffer.

You can use one or the other. That is to say you cannot use this API if you specified that this buffer has a staging buffer, which means you'll use that API (getStagingBuffer, syncToGPU)

GLuint makVrv::DtGlBuffer::handle

(

void

)

const

The internal GL handle of the buffer.

void makVrv::DtGlBuffer::tearDown

(

void

)

const

static bool makVrv::DtGlBuffer::resizeBufferIfNecessary ( DtGlBuffer *&  buffer, const char *  name, DtBufferType  bufferType, int  sizeInBytesNeeded, DtUsage  usage, DtCpuAccess  accessType, bool  hasStaging, const void *  data  )

static

Resize the buffer, only if necessary If buffer is null, will create a DtGlBuffer with the requested type and size If buffer is not null and requested size is < its actual size it will resize the buffer to be the requested size.

This used to completely recreate the buffer but that does not work will with large buffers. It causes opengl to allocate way too much memory

Member Data Documentation

std::string makVrv::DtGlBuffer::myName

protected

GLuint makVrv::DtGlBuffer::myHandle

mutableprotected

GLenum makVrv::DtGlBuffer::myType

protected

int makVrv::DtGlBuffer::mySizeInBytes

protected

GLubyte* makVrv::DtGlBuffer::myStagingBufffer

protected

bool makVrv::DtGlBuffer::myHasStagingBuffer

protected

DtUsage makVrv::DtGlBuffer::myUsage

protected

DtCpuAccess makVrv::DtGlBuffer::myAccessType

protected

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

• /exports/nfedora7-1/nightly/docs/vrforcesDevelopment.vrf4-6-branch/include/vrvGraphicsUtils/DtGlBuffer.h