QGLBuffer

Note

This class was introduced in Qt 4.7

Synopsis

Functions

• def allocate (count)
• def allocate (data[, count=-1])
• def bind ()
• def bufferId ()
• def create ()
• def destroy ()
• def isCreated ()
• def map (access)
• def read (offset, count)
• def release ()
• def setUsagePattern (value)
• def size ()
• def type ()
• def unmap ()
• def usagePattern ()
• def write (offset, data[, count=-1])

Static functions

• def release (type)

Detailed Description

The PySide.QtOpenGL.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.

PySide.QtOpenGL.QGLBuffer objects can be copied around as a reference to the underlying GL buffer object:

QGLBuffer buffer1(QGLBuffer::IndexBuffer);
buffer1.create();

QGLBuffer buffer2 = buffer1;

PySide.QtOpenGL.QGLBuffer performs a shallow copy when objects are copied in this manner, but does not implement copy-on-write semantics. The original object will be affected whenever the copy is modified.

class PySide.QtOpenGL.QGLBuffer

class PySide.QtOpenGL.QGLBuffer(type)

class PySide.QtOpenGL.QGLBuffer(other)

Parameters:

• other – PySide.QtOpenGL.QGLBuffer
• type – PySide.QtOpenGL.QGLBuffer.Type

Constructs a new buffer object of type QGLBuffer.VertexBuffer .

Note: this constructor just creates the PySide.QtOpenGL.QGLBuffer instance. The actual buffer object in the GL server is not created until PySide.QtOpenGL.QGLBuffer.create() is called.

See also

PySide.QtOpenGL.QGLBuffer.create()

Constructs a shallow copy of other .

Note: PySide.QtOpenGL.QGLBuffer does not implement copy-on-write semantics, so other will be affected whenever the copy is modified.

PySide.QtOpenGL.QGLBuffer.Access

This enum defines the access mode for QGLBuffer.map() .

Constant	Description
QGLBuffer.ReadOnly	The buffer will be mapped for reading only.
QGLBuffer.WriteOnly	The buffer will be mapped for writing only.
QGLBuffer.ReadWrite	The buffer will be mapped for reading and writing.

Note

This enum was introduced or modified in Qt 4.7

PySide.QtOpenGL.QGLBuffer.UsagePattern

This enum defines the usage pattern of a PySide.QtOpenGL.QGLBuffer object.

Constant	Description
QGLBuffer.StreamDraw	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	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	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	The data will be set once and used many times for drawing operations.
QGLBuffer.StaticRead	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	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	The data will be modified repeatedly and used many times for drawing operations.
QGLBuffer.DynamicRead	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	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.

Note

This enum was introduced or modified in Qt 4.7

PySide.QtOpenGL.QGLBuffer.Type

This enum defines the type of GL buffer object to create with PySide.QtOpenGL.QGLBuffer .

Constant	Description
QGLBuffer.VertexBuffer	Vertex buffer object for use when specifying vertex arrays.
QGLBuffer.IndexBuffer	Index buffer object for use with glDrawElements().
QGLBuffer.PixelPackBuffer	Pixel pack buffer object for reading pixel data from the GL server (for example, with glReadPixels()). Not supported under OpenGL/ES.
QGLBuffer.PixelUnpackBuffer	Pixel unpack buffer object for writing pixel data to the GL server (for example, with glTexImage2D()). Not supported under OpenGL/ES.

Note

This enum was introduced or modified in Qt 4.7

PySide.QtOpenGL.QGLBuffer.allocate(data[, count=-1])

Parameters:

• data – void
• count – PySide.QtCore.int

Allocates count bytes of space to the buffer, initialized to the contents of data . Any previous contents will be removed.

It is assumed that PySide.QtOpenGL.QGLBuffer.create() has been called on this buffer and that it has been bound to the current context.

See also

PySide.QtOpenGL.QGLBuffer.create() PySide.QtOpenGL.QGLBuffer.read() PySide.QtOpenGL.QGLBuffer.write()

PySide.QtOpenGL.QGLBuffer.allocate(count)

Parameters:count – PySide.QtCore.int

This is an overloaded function.

Allocates count bytes of space to the buffer. Any previous contents will be removed.

It is assumed that PySide.QtOpenGL.QGLBuffer.create() has been called on this buffer and that it has been bound to the current context.

See also

PySide.QtOpenGL.QGLBuffer.create() PySide.QtOpenGL.QGLBuffer.write()

PySide.QtOpenGL.QGLBuffer.bind()

Return type:PySide.QtCore.bool

Binds the buffer associated with this object to the current GL context. Returns false if binding was not possible, usually because PySide.QtOpenGL.QGLBuffer.type() is not supported on this GL implementation.

The buffer must be bound to the same PySide.QtOpenGL.QGLContext current when PySide.QtOpenGL.QGLBuffer.create() was called, or to another PySide.QtOpenGL.QGLContext that is sharing with it. Otherwise, false will be returned from this function.

See also

PySide.QtOpenGL.QGLBuffer.release() PySide.QtOpenGL.QGLBuffer.create()

PySide.QtOpenGL.QGLBuffer.bufferId()

Return type:long

Returns the GL identifier associated with this buffer; zero if the buffer has not been created.

See also

PySide.QtOpenGL.QGLBuffer.isCreated()

PySide.QtOpenGL.QGLBuffer.create()

Return type:PySide.QtCore.bool

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 PySide.QtOpenGL.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 PySide.QtOpenGL.QGLContext .

See also

PySide.QtOpenGL.QGLBuffer.isCreated() PySide.QtOpenGL.QGLBuffer.allocate() PySide.QtOpenGL.QGLBuffer.write() PySide.QtOpenGL.QGLBuffer.destroy()

PySide.QtOpenGL.QGLBuffer.destroy()

Destroys this buffer object, including the storage being used in the GL server. All references to the buffer will become invalid.

PySide.QtOpenGL.QGLBuffer.isCreated()

Return type:PySide.QtCore.bool

Returns true if this buffer has been created; false otherwise.

See also

PySide.QtOpenGL.QGLBuffer.create() PySide.QtOpenGL.QGLBuffer.destroy()

PySide.QtOpenGL.QGLBuffer.map(access)

Parameters:access – PySide.QtOpenGL.QGLBuffer.Access Return type:void

PySide.QtOpenGL.QGLBuffer.read(offset, count)

Parameters:

• offset – PySide.QtCore.int
• count – PySide.QtCore.int

Return type:

(retval, data)

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.

See also

PySide.QtOpenGL.QGLBuffer.write() PySide.QtOpenGL.QGLBuffer.bind()

static PySide.QtOpenGL.QGLBuffer.release(type)

Parameters:type – PySide.QtOpenGL.QGLBuffer.Type

PySide.QtOpenGL.QGLBuffer.release()

Releases the buffer associated with this object from the current GL context.

This function must be called with the same PySide.QtOpenGL.QGLContext current as when PySide.QtOpenGL.QGLBuffer.bind() was called on the buffer.

See also

PySide.QtOpenGL.QGLBuffer.bind()

PySide.QtOpenGL.QGLBuffer.setUsagePattern(value)

Parameters:value – PySide.QtOpenGL.QGLBuffer.UsagePattern

PySide.QtOpenGL.QGLBuffer.size()

Return type:PySide.QtCore.int

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

PySide.QtOpenGL.QGLBuffer.isCreated() PySide.QtOpenGL.QGLBuffer.bind()

PySide.QtOpenGL.QGLBuffer.type()

Return type:PySide.QtOpenGL.QGLBuffer.Type

Returns the type of buffer represented by this object.

PySide.QtOpenGL.QGLBuffer.unmap()

Return type:PySide.QtCore.bool

Unmaps the buffer after it was mapped into the application’s memory space with a previous call to PySide.QtOpenGL.QGLBuffer.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 PySide.QtOpenGL.QGLBuffer.map() .

This function is only supported under OpenGL/ES if the GL_OES_mapbuffer extension is present.

See also

PySide.QtOpenGL.QGLBuffer.map()

PySide.QtOpenGL.QGLBuffer.usagePattern()

Return type:PySide.QtOpenGL.QGLBuffer.UsagePattern

Returns the usage pattern for this buffer object. The default value is StaticDraw .

See also

PySide.QtOpenGL.QGLBuffer.setUsagePattern()

PySide.QtOpenGL.QGLBuffer.write(offset, data[, count=-1])

Parameters:

• offset – PySide.QtCore.int
• data – void
• count – PySide.QtCore.int

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 PySide.QtOpenGL.QGLBuffer.create() has been called on this buffer and that it has been bound to the current context.

See also

PySide.QtOpenGL.QGLBuffer.create() PySide.QtOpenGL.QGLBuffer.read() PySide.QtOpenGL.QGLBuffer.allocate()