glgetbufferparameteriv(3g) [debian man page]
GLGETBUFFERPARAMETER(3G) [FIXME: manual] GLGETBUFFERPARAMETER(3G) NAME
glGetBufferParameteriv - return parameters of a buffer object C SPECIFICATION
void glGetBufferParameteriv(GLenum target, GLenum value, GLint * data); PARAMETERS
target Specifies the target buffer object. The symbolic constant must be GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER, GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TEXTURE_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER, or GL_UNIFORM_BUFFER. value Specifies the symbolic name of a buffer object parameter. Accepted values are GL_BUFFER_ACCESS, GL_BUFFER_MAPPED, GL_BUFFER_SIZE, or GL_BUFFER_USAGE. data Returns the requested parameter. DESCRIPTION
glGetBufferParameteriv returns in data a selected parameter of the buffer object specified by target. value names a specific buffer object parameter, as follows: GL_BUFFER_ACCESS params returns the access policy set while mapping the buffer object. The initial value is GL_READ_WRITE. GL_BUFFER_MAPPED params returns a flag indicating whether the buffer object is currently mapped. The initial value is GL_FALSE. GL_BUFFER_SIZE params returns the size of the buffer object, measured in bytes. The initial value is 0. GL_BUFFER_USAGE params returns the buffer object's usage pattern. The initial value is GL_STATIC_DRAW. NOTES
If an error is generated, no change is made to the contents of data. ERRORS
GL_INVALID_ENUM is generated if target or value is not an accepted value. GL_INVALID_OPERATION is generated if the reserved buffer object name 0 is bound to target. SEE ALSO
glBindBuffer(), glBufferData(), glMapBuffer(), glUnmapBuffer() COPYRIGHT
Copyright (C) 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/. [FIXME: source] 05/30/2012 GLGETBUFFERPARAMETER(3G)
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GLMAPBUFFER(3G) OpenGL 3.3 GLMAPBUFFER(3G) NAME
glMapBuffer - map a buffer object's data store C SPECIFICATION
void * glMapBuffer(GLenum target, GLenum access); PARAMETERS
target Specifies the target buffer object being mapped. The symbolic constant must be GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER, GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TEXTURE_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER or GL_UNIFORM_BUFFER. access Specifies the access policy, indicating whether it will be possible to read from, write to, or both read from and write to the buffer object's mapped data store. The symbolic constant must be GL_READ_ONLY, GL_WRITE_ONLY, or GL_READ_WRITE. C SPECIFICATION
GLboolean glUnmapBuffer(GLenum target); PARAMETERS
target Specifies the target buffer object being unmapped. The symbolic constant must be GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER, GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TEXTURE_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER or GL_UNIFORM_BUFFER. DESCRIPTION
glMapBuffer maps to the client's address space the entire data store of the buffer object currently bound to target. The data can then be directly read and/or written relative to the returned pointer, depending on the specified access policy. If the GL is unable to map the buffer object's data store, glMapBuffer generates an error and returns NULL. This may occur for system-specific reasons, such as low virtual memory availability. If a mapped data store is accessed in a way inconsistent with the specified access policy, no error is generated, but performance may be negatively impacted and system errors, including program termination, may result. Unlike the usage parameter of glBufferData, access is not a hint, and does in fact constrain the usage of the mapped data store on some GL implementations. In order to achieve the highest performance available, a buffer object's data store should be used in ways consistent with both its specified usage and access parameters. A mapped data store must be unmapped with glUnmapBuffer before its buffer object is used. Otherwise an error will be generated by any GL command that attempts to dereference the buffer object's data store. When a data store is unmapped, the pointer to its data store becomes invalid. glUnmapBuffer returns GL_TRUE unless the data store contents have become corrupt during the time the data store was mapped. This can occur for system-specific reasons that affect the availability of graphics memory, such as screen mode changes. In such situations, GL_FALSE is returned and the data store contents are undefined. An application must detect this rare condition and reinitialize the data store. A buffer object's mapped data store is automatically unmapped when the buffer object is deleted or its data store is recreated with glBufferData. NOTES
If an error is generated, glMapBuffer returns NULL, and glUnmapBuffer returns GL_FALSE. Parameter values passed to GL commands may not be sourced from the returned pointer. No error will be generated, but results will be undefined and will likely vary across GL implementations. ERRORS
GL_INVALID_ENUM is generated if target is not GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER, GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TEXTURE_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER or GL_UNIFORM_BUFFER. GL_INVALID_ENUM is generated if access is not GL_READ_ONLY, GL_WRITE_ONLY, or GL_READ_WRITE. GL_OUT_OF_MEMORY is generated when glMapBuffer is executed if the GL is unable to map the buffer object's data store. This may occur for a variety of system-specific reasons, such as the absence of sufficient remaining virtual memory. GL_INVALID_OPERATION is generated if the reserved buffer object name 0 is bound to target. GL_INVALID_OPERATION is generated if glMapBuffer is executed for a buffer object whose data store is already mapped. GL_INVALID_OPERATION is generated if glUnmapBuffer is executed for a buffer object whose data store is not currently mapped. ASSOCIATED GETS
glGetBufferPointerv() with argument GL_BUFFER_MAP_POINTER glGetBufferParameter() with argument GL_BUFFER_MAPPED, GL_BUFFER_ACCESS, or GL_BUFFER_USAGE SEE ALSO
glBindBuffer(), glBindBufferBase(), glBindBufferRange(), glBufferData(), glBufferSubData(), glDeleteBuffers() COPYRIGHT
Copyright (C) 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/. OpenGL 3.3 03/08/2011 GLMAPBUFFER(3G)