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The QGLBuffer class provides functions for creating and managing GL buffer objects. More...
#include <QGLBuffer>
This class was introduced in Qt 4.7.
enum | Access { ReadOnly, WriteOnly, ReadWrite } |
enum | Type { VertexBuffer, IndexBuffer, PixelPackBuffer, PixelUnpackBuffer } |
enum | UsagePattern { StreamDraw, StreamRead, StreamCopy, StaticDraw, ..., DynamicCopy } |
QGLBuffer ( QGLBuffer::Type type ) | |
~QGLBuffer () | |
void | allocate ( const void * data, int count ) |
void | allocate ( int count ) |
bool | bind () const |
uint | bufferId () const |
bool | create () |
bool | isCreated () const |
void * | map ( QGLBuffer::Access access ) |
bool | read ( int offset, void * data, int count ) |
void | release () const |
void | setUsagePattern ( QGLBuffer::UsagePattern value ) |
int | size () const |
QGLBuffer::Type | type () const |
bool | unmap () |
QGLBuffer::UsagePattern | usagePattern () const |
void | write ( int offset, const void * data, int count ) |
The QGLBuffer class provides functions for creating and managing GL buffer objects.
Buffer objects are created in the GL server so that the client application can avoid uploading vertices, indices, texture image data, etc every time they are needed.
This enum defines the access mode for QGLBuffer::map().
Constant | Value | Description |
---|---|---|
QGLBuffer::ReadOnly | 0x88B8 | The buffer will be mapped for reading only. |
QGLBuffer::WriteOnly | 0x88B9 | The buffer will be mapped for writing only. |
QGLBuffer::ReadWrite | 0x88BA | The buffer will be mapped for reading and writing. |
This enum defines the type of GL buffer object to create with QGLBuffer.
Constant | Value | Description |
---|---|---|
QGLBuffer::VertexBuffer | 0x8892 | Vertex buffer object for use when specifying vertex arrays. |
QGLBuffer::IndexBuffer | 0x8893 | Index buffer object for use with glDrawElements(). |
QGLBuffer::PixelPackBuffer | 0x88EB | Pixel pack buffer object for reading pixel data from the GL server (for example, with glReadPixels()). Not supported under OpenGL/ES. |
QGLBuffer::PixelUnpackBuffer | 0x88EC | Pixel unpack buffer object for writing pixel data to the GL server (for example, with glTexImage2D()). Not supported under OpenGL/ES. |
This enum defines the usage pattern of a QGLBuffer object.
Constant | Value | Description |
---|---|---|
QGLBuffer::StreamDraw | 0x88E0 | The data will be set once and used a few times for drawing operations. Under OpenGL/ES 1.1 this is identical to StaticDraw. |
QGLBuffer::StreamRead | 0x88E1 | The data will be set once and used a few times for reading data back from the GL server. Not supported under OpenGL/ES. |
QGLBuffer::StreamCopy | 0x88E2 | The data will be set once and used a few times for reading data back from the GL server for use in further drawing operations. Not supported under OpenGL/ES. |
QGLBuffer::StaticDraw | 0x88E4 | The data will be set once and used many times for drawing operations. |
QGLBuffer::StaticRead | 0x88E5 | The data will be set once and used many times for reading data back from the GL server. Not supported under OpenGL/ES. |
QGLBuffer::StaticCopy | 0x88E6 | The data will be set once and used many times for reading data back from the GL server for use in further drawing operations. Not supported under OpenGL/ES. |
QGLBuffer::DynamicDraw | 0x88E8 | The data will be modified repeatedly and used many times for drawing operations. |
QGLBuffer::DynamicRead | 0x88E9 | The data will be modified repeatedly and used many times for reading data back from the GL server. Not supported under OpenGL/ES. |
QGLBuffer::DynamicCopy | 0x88EA | The data will be modified repeatedly and used many times for reading data back from the GL server for use in further drawing operations. Not supported under OpenGL/ES. |
Constructs a new buffer object of type.
Note: this constructor just creates the QGLBuffer instance. The actual buffer object in the GL server is not created until create() is called.
See also create().
Destroys this buffer object, including the storage being used in the GL server.
Allocates count bytes of space to the buffer, initialized to the contents of data. Any previous contents will be removed.
It is assumed that create() has been called on this buffer and that it has been bound to the current context.
See also create(), read(), and write().
This is an overloaded function.
Allocates count bytes of space to the buffer. Any previous contents will be removed.
It is assumed that create() has been called on this buffer and that it has been bound to the current context.
See also create() and write().
Binds the buffer associated with this object to the current GL context. Returns false if binding was not possible, usually because type() is not supported on this GL implementation.
The buffer must be bound to the same QGLContext current when create() was called, or to another QGLContext that is sharing with it. Otherwise, false will be returned from this function.
See also release() and create().
Returns the GL identifier associated with this buffer; zero if the buffer has not been created.
See also isCreated().
Creates the buffer object in the GL server. Returns true if the object was created; false otherwise.
This function must be called with a current QGLContext. The buffer will be bound to and can only be used in that context (or any other context that is shared with it).
This function will return false if the GL implementation does not support buffers, or there is no current QGLContext.
See also isCreated(), allocate(), and write().
Returns true if this buffer has been created; false otherwise.
See also create().
Maps the contents of this buffer into the application's memory space and returns a pointer to it. Returns null if memory mapping is not possible. The access parameter indicates the type of access to be performed.
It is assumed that create() has been called on this buffer and that it has been bound to the current context.
This function is only supported under OpenGL/ES if the GL_OES_mapbuffer extension is present.
See also unmap(), create(), and bind().
Reads the count bytes in this buffer starting at offset into data. Returns true on success; false if reading from the buffer is not supported. Buffer reading is not supported under OpenGL/ES.
It is assumed that this buffer has been bound to the current context.
Releases the buffer associated with this object from the current GL context.
This function must be called with the same QGLContext current as when bind() was called on the buffer.
See also bind().
Sets the usage pattern for this buffer object to value. This function must be called before allocate() or write().
See also usagePattern(), allocate(), and write().
Returns the size of the data in this buffer, for reading operations. Returns -1 if fetching the buffer size is not supported, or the buffer has not been created.
It is assumed that this buffer has been bound to the current context.
See also isCreated() and bind().
Returns the type of buffer represented by this object.
Unmaps the buffer after it was mapped into the application's memory space with a previous call to map(). Returns true if the unmap succeeded; false otherwise.
It is assumed that this buffer has been bound to the current context, and that it was previously mapped with map().
This function is only supported under OpenGL/ES if the GL_OES_mapbuffer extension is present.
See also map().
Returns the usage pattern for this buffer object. The default value is StaticDraw.
See also setUsagePattern().
Replaces the count bytes of this buffer starting at offset with the contents of data. Any other bytes in the buffer will be left unmodified.
It is assumed that create() has been called on this buffer and that it has been bound to the current context.
See also create(), read(), and allocate().
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