The QOpenGLBuffer class provides functions for creating and managing OpenGL buffer objects. 更多...
| 头： | #include <QOpenGLBuffer> |
| qmake: | QT += gui |
| Since: | Qt 5.0 |
| enum | Access { ReadOnly, WriteOnly, ReadWrite } |
| enum | RangeAccessFlag { RangeRead, RangeWrite, RangeInvalidate, RangeInvalidateBuffer, RangeFlushExplicit, RangeUnsynchronized } |
| flags | RangeAccessFlags |
| enum | Type { VertexBuffer, IndexBuffer, PixelPackBuffer, PixelUnpackBuffer } |
| enum | UsagePattern { StreamDraw, StreamRead, StreamCopy, StaticDraw, ..., DynamicCopy } |
| QOpenGLBuffer () | |
| QOpenGLBuffer (QOpenGLBuffer::Type type ) | |
| QOpenGLBuffer (const QOpenGLBuffer & other ) | |
| ~QOpenGLBuffer () | |
| void | allocate (const void * data , int count ) |
| void | allocate (int count ) |
| bool | bind () |
| GLuint | bufferId () const |
| bool | create () |
| void | destroy () |
| bool | isCreated () const |
| void * | map (QOpenGLBuffer::Access access ) |
| void * | mapRange (int offset , int count , QOpenGLBuffer::RangeAccessFlags access ) |
| bool | read (int offset , void * data , int count ) |
| void | release () |
| void | setUsagePattern (QOpenGLBuffer::UsagePattern value ) |
| int | size () const |
| QOpenGLBuffer::Type | type () const |
| bool | unmap () |
| QOpenGLBuffer::UsagePattern | usagePattern () const |
| void | write (int offset , const void * data , int count ) |
| QOpenGLBuffer & | operator= (const QOpenGLBuffer & other ) |
| void | release (QOpenGLBuffer::Type type ) |
The QOpenGLBuffer class provides functions for creating and managing OpenGL buffer objects.
Buffer objects are created in the OpenGL server so that the client application can avoid uploading vertices, indices, texture image data, etc every time they are needed.
QOpenGLBuffer objects can be copied around as a reference to the underlying OpenGL buffer object:
QOpenGLBuffer buffer1(QOpenGLBuffer::IndexBuffer);
buffer1.create();
QOpenGLBuffer buffer2 = buffer1;
QOpenGLBuffer 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.
This enum defines the access mode for QOpenGLBuffer::map ().
| 常量 | 值 | 描述 |
|---|---|---|
QOpenGLBuffer::ReadOnly
|
0x88B8
|
The buffer will be mapped for reading only. |
QOpenGLBuffer::WriteOnly
|
0x88B9
|
The buffer will be mapped for writing only. |
QOpenGLBuffer::ReadWrite
|
0x88BA
|
The buffer will be mapped for reading and writing. |
This enum defines the access mode bits for QOpenGLBuffer::mapRange ().
| 常量 | 值 | 描述 |
|---|---|---|
QOpenGLBuffer::RangeRead
|
0x0001
|
The buffer will be mapped for reading. |
QOpenGLBuffer::RangeWrite
|
0x0002
|
The buffer will be mapped for writing. |
QOpenGLBuffer::RangeInvalidate
|
0x0004
|
Discard the previous contents of the specified range. |
QOpenGLBuffer::RangeInvalidateBuffer
|
0x0008
|
Discard the previous contents of the entire buffer. |
QOpenGLBuffer::RangeFlushExplicit
|
0x0010
|
Indicates that modifications are to be flushed explicitly via
glFlushMappedBufferRange
.
|
QOpenGLBuffer::RangeUnsynchronized
|
0x0020
|
Indicates that pending operations should not be synchronized before returning from mapRange (). |
The RangeAccessFlags type is a typedef for QFlags <RangeAccessFlag>. It stores an OR combination of RangeAccessFlag values.
This enum defines the type of OpenGL buffer object to create with QOpenGLBuffer .
| 常量 | 值 | 描述 |
|---|---|---|
QOpenGLBuffer::VertexBuffer
|
0x8892
|
Vertex buffer object for use when specifying vertex arrays. |
QOpenGLBuffer::IndexBuffer
|
0x8893
|
Index buffer object for use with
glDrawElements()
.
|
QOpenGLBuffer::PixelPackBuffer
|
0x88EB
|
Pixel pack buffer object for reading pixel data from the OpenGL server (for example, with
glReadPixels()
). Not supported under OpenGL/ES.
|
QOpenGLBuffer::PixelUnpackBuffer
|
0x88EC
|
Pixel unpack buffer object for writing pixel data to the OpenGL server (for example, with
glTexImage2D()
). Not supported under OpenGL/ES.
|
This enum defines the usage pattern of a QOpenGLBuffer 对象。
| 常量 | 值 | 描述 |
|---|---|---|
QOpenGLBuffer::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. |
QOpenGLBuffer::StreamRead
|
0x88E1
|
The data will be set once and used a few times for reading data back from the OpenGL server. Not supported under OpenGL/ES. |
QOpenGLBuffer::StreamCopy
|
0x88E2
|
The data will be set once and used a few times for reading data back from the OpenGL server for use in further drawing operations. Not supported under OpenGL/ES. |
QOpenGLBuffer::StaticDraw
|
0x88E4
|
The data will be set once and used many times for drawing operations. |
QOpenGLBuffer::StaticRead
|
0x88E5
|
The data will be set once and used many times for reading data back from the OpenGL server. Not supported under OpenGL/ES. |
QOpenGLBuffer::StaticCopy
|
0x88E6
|
The data will be set once and used many times for reading data back from the OpenGL server for use in further drawing operations. Not supported under OpenGL/ES. |
QOpenGLBuffer::DynamicDraw
|
0x88E8
|
The data will be modified repeatedly and used many times for drawing operations. |
QOpenGLBuffer::DynamicRead
|
0x88E9
|
The data will be modified repeatedly and used many times for reading data back from the OpenGL server. Not supported under OpenGL/ES. |
QOpenGLBuffer::DynamicCopy
|
0x88EA
|
The data will be modified repeatedly and used many times for reading data back from the OpenGL server for use in further drawing operations. Not supported under OpenGL/ES. |
Constructs a new buffer object of type QOpenGLBuffer::VertexBuffer .
Note: this constructor just creates the QOpenGLBuffer instance. The actual buffer object in the OpenGL server is not created until create () 被调用。
另请参阅 create ().
Constructs a new buffer object of type .
Note: this constructor just creates the QOpenGLBuffer instance. The actual buffer object in the OpenGL server is not created until create () 被调用。
另请参阅 create ().
Constructs a shallow copy of other .
注意： QOpenGLBuffer does not implement copy-on-write semantics, so other will be affected whenever the copy is modified.
Destroys this buffer object, including the storage being used in the OpenGL 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.
另请参阅 create (), read ()，和 write ().
这是重载函数。
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.
Binds the buffer associated with this object to the current OpenGL context. Returns
false
if binding was not possible, usually because
type
() is not supported on this OpenGL implementation.
The buffer must be bound to the same QOpenGLContext current when create () was called, or to another QOpenGLContext that is sharing with it. Otherwise, false will be returned from this function.
Returns the OpenGL identifier associated with this buffer; zero if the buffer has not been created.
另请参阅 isCreated ().
Creates the buffer object in the OpenGL server. Returns
true
if the object was created; false otherwise.
This function must be called with a current QOpenGLContext . 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 OpenGL implementation does not support buffers, or there is no current QOpenGLContext .
另请参阅 isCreated (), allocate (), write ()，和 destroy ().
Destroys this buffer object, including the storage being used in the OpenGL server. All references to the buffer will become invalid.
返回
true
if this buffer has been created; false otherwise.
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.
注意：
This function is only supported under OpenGL ES 2.0 or earlier if the
GL_OES_mapbuffer
extension is present.
注意：
On OpenGL ES 3.0 and newer, or, in case if desktop OpenGL, if
GL_ARB_map_buffer_range
is supported, this function uses
glMapBufferRange
而不是
glMapBuffer
.
另请参阅 unmap (), create (), bind ()，和 mapRange ().
Maps the range specified by offset and count of 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 specifies a combination of access flags.
It is assumed that create () has been called on this buffer and that it has been bound to the current context.
注意： This function is not available on OpenGL ES 2.0 and earlier.
另请参阅 unmap (), create ()，和 bind ().
读取
count
bytes in this buffer starting at
offset
into
data
。返回
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 OpenGL context.
This function must be called with the same QOpenGLContext current as when bind () was called on the buffer.
另请参阅 bind ().
[static]
void
QOpenGLBuffer::
release
(
QOpenGLBuffer::Type
type
)
Releases the buffer associated with type in the current QOpenGLContext .
This function is a direct call to
glBindBuffer(type, 0)
for use when the caller does not know which
QOpenGLBuffer
has been bound to the context but wants to make sure that it is released.
QOpenGLBuffer::release(QOpenGLBuffer::VertexBuffer);
Sets the usage pattern for this buffer object to value . This function must be called before allocate () 或 write ().
另请参阅 usagePattern (), allocate ()，和 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.
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
()。返回
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 ().
注意：
This function is only supported under OpenGL ES 2.0 and earlier if the
GL_OES_mapbuffer
extension is present.
另请参阅 map ().
Returns the usage pattern for this buffer object. The default value is StaticDraw .
另请参阅 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.
另请参阅 create (), read ()，和 allocate ().
Assigns a shallow copy of other 到此对象。
注意： QOpenGLBuffer does not implement copy-on-write semantics, so other will be affected whenever the copy is modified.