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
.
size
Specifies 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 bytes be a multiple of .
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.
// data_size_in_bytes is the size in bytes of your vertex data. // data_vertices is your actual vertex data, probably a huge array of floats GLuint vertex_buffer; // Save this for later rendering glGenBuffers(1, &vertex_buffer); glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); glBufferData(GL_ARRAY_BUFFER, data_size_in_bytes, 0, GL_STATIC_DRAW); glBufferSubData(GL_ARRAY_BUFFER, 0, data_size_in_bytes, data_vertices); GLint size = 0; glGetBufferParameteriv(GL_ARRAY_BUFFER, GL_BUFFER_SIZE, &size); if(data_size_in_bytes != size) { glDeleteBuffers(1, &vertex_buffer); // Log the error return; } // Success
// data_size_in_bytes is the size in bytes of your vertex data. // data_indices is an array of integer offsets into your vertex data. GLuint index_buffer; // Save this for later rendering glGenBuffers(1, &index_buffer); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_buffer); glBufferData(GL_ELEMENT_ARRAY_BUFFER, data_size_in_bytes, 0, GL_STATIC_DRAW); glBufferSubData(GL_ELEMENT_ARRAY_BUFFER, 0, data_size_in_bytes, data_indices); GLint size = 0; glGetBufferParameteriv(GL_ELEMENT_ARRAY_BUFFER, GL_BUFFER_SIZE, &size); if(data_size_in_bytes != size) { glDeleteBuffers(1, &index_buffer); // Log the error return; } // Success
Songho - OpenGL Pixel Buffer Object (PBO)
Songho - OpenGL Vertex Buffer Object (VBO)
open.gl - The Graphics Pipeline
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. https://opencontent.org/openpub/.