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glBufferData — creates and initializes a buffer object's data store
void glBufferData( | GLenum | target, |
| GLsizeiptr | size, | |
| const GLvoid * | data, | |
| GLenum | usage); |
target
Specifies the target buffer object.
The symbolic constant must be GL_ARRAY_BUFFER,
GL_ELEMENT_ARRAY_BUFFER,
GL_PIXEL_PACK_BUFFER, or
GL_PIXEL_UNPACK_BUFFER.
sizeSpecifies the size in bytes of the buffer object's new data store.
data
Specifies a pointer to data that will be copied into the data store for initialization,
or NULL if no data is to be copied.
usage
Specifies the expected usage pattern of the data store. The symbolic constant must be
GL_STREAM_DRAW, GL_STREAM_READ, GL_STREAM_COPY,
GL_STATIC_DRAW, GL_STATIC_READ, GL_STATIC_COPY,
GL_DYNAMIC_DRAW, GL_DYNAMIC_READ, or GL_DYNAMIC_COPY.
glBufferData creates a new data store for the buffer object currently bound to
target. Any pre-existing data store is deleted. The new data store is created with the
specified size in bytes and usage. If data
is not NULL, the data store is initialized with data from this pointer. In its initial
state, the new data store is not mapped, it has a NULL mapped pointer, and its mapped access
is GL_READ_WRITE.
usage is a hint to the GL implementation as to how a buffer object's data store will be
accessed. This enables the GL implementation to make more intelligent decisions that may significantly
impact buffer object performance. It does not, however, constrain the actual usage of the data store.
usage can be broken down into two parts: first, the frequency of access (modification
and usage), and second, the nature of that access. The frequency of access may be one of these:
The data store contents will be modified once and used at most a few times.
The data store contents will be modified once and used many times.
The data store contents will be modified repeatedly and used many times.
The nature of access may be one of these:
The data store contents are modified by the application, and used as the source for GL drawing and image specification commands.
The data store contents are modified by reading data from the GL, and used to return that data when queried by the application.
The data store contents are modified by reading data from the GL, and used as the source for GL drawing and image specification commands.
glBufferData is available only if the GL version is 1.5 or greater.
Targets GL_PIXEL_PACK_BUFFER and GL_PIXEL_UNPACK_BUFFER are available
only if the GL version is 2.1 or greater.
If data is NULL, a data store of the specified size is still created,
but its contents remain uninitialized and thus undefined.
Clients must align data elements consistent with the requirements of the client
platform, with an additional base-level requirement that an offset within a buffer to
a datum comprising
GL_INVALID_ENUM is generated if target is not
GL_ARRAY_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
GL_PIXEL_PACK_BUFFER, or GL_PIXEL_UNPACK_BUFFER.
GL_INVALID_ENUM is generated if usage is not
GL_STREAM_DRAW, GL_STREAM_READ, GL_STREAM_COPY,
GL_STATIC_DRAW, GL_STATIC_READ, GL_STATIC_COPY,
GL_DYNAMIC_DRAW, GL_DYNAMIC_READ, or GL_DYNAMIC_COPY.
GL_INVALID_VALUE is generated if size is negative.
GL_INVALID_OPERATION is generated if the reserved buffer object name 0 is bound to target.
GL_OUT_OF_MEMORY is generated if the GL is unable to create a data store with the specified size.
GL_INVALID_OPERATION is generated if glBufferData
is executed between the execution of
glBegin and the corresponding execution of
glEnd.
Copyright © 2005 Addison-Wesley. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.