Name ARB_buffer_storage Name Strings GL_ARB_buffer_storage Contact Graham Sellers (graham.sellers 'at' amd.com) Contributors Jeff Bolz, NVIDIA Daniel Koch, NVIDIA Jon Leech Mark Kilgard, NVIDIA Notice Copyright (c) 2013 The Khronos Group Inc. Copyright terms at http://www.khronos.org/registry/speccopyright.html Specification Update Policy Khronos-approved extension specifications are updated in response to issues and bugs prioritized by the Khronos OpenGL Working Group. For extensions which have been promoted to a core Specification, fixes will first appear in the latest version of that core Specification, and will eventually be backported to the extension document. This policy is described in more detail at https://www.khronos.org/registry/OpenGL/docs/update_policy.php Status Complete. Approved by the ARB on June 3, 2013. Ratified by the Khronos Board of Promoters on July 19, 2013. Version Last Modified Date: April 20, 2015 Revision: 25 Number ARB Extension #144 Dependencies This extension is written against version 4.3 of the Core Profile OpenGL Specification, dated August 6, 2012. The definition of this extension is affected by the presence of GL_EXT_direct_state_access. Overview OpenGL has long supported buffer objects as a means of storing data that may be used to source vertex attributes, pixel data for textures, uniforms and other elements. In un-extended GL, buffer data stores are mutable - that is, they may be de-allocated or resized while they are in use. The GL_ARB_texture_storage extension added immutable storage for texture object (and was subsequently incorporated into OpenGL 4.2). This extension further applies the concept of immutable storage to buffer objects. If an implementation is aware of a buffer's immutability, it may be able to make certain assumptions or apply particular optimizations in order to increase performance or reliability. Furthermore, this extension allows applications to pass additional information about a requested allocation to the implementation which it may use to select memory heaps, caching behavior or allocation strategies. Finally, this extension introduces the concept of persistent client mappings of buffer objects, which allow clients to retain pointers to a buffer's data store returned as the result of a mapping, and to issue drawing commands while those mappings are in place. New Procedures and Functions void BufferStorage(enum target, sizeiptr size, const void * data, bitfield flags); When EXT_direct_state_access is present: void NamedBufferStorageEXT(uint buffer, sizeiptr size, const void * data, bitfield flags); New Tokens Accepted in the parameter of BufferStorage and NamedBufferStorageEXT: MAP_READ_BIT 0x0001 (existing) MAP_WRITE_BIT 0x0002 (existing) MAP_PERSISTENT_BIT 0x0040 MAP_COHERENT_BIT 0x0080 DYNAMIC_STORAGE_BIT 0x0100 CLIENT_STORAGE_BIT 0x0200 Accepted as part of the parameter to MapBufferRange: MAP_PERSISTENT_BIT 0x00000040 MAP_COHERENT_BIT 0x00000080 Accepted by the parameter of GetBufferParameter{i|i64}v: BUFFER_IMMUTABLE_STORAGE 0x821F BUFFER_STORAGE_FLAGS 0x8220 Accepted by the parameter of MemoryBarrier: CLIENT_MAPPED_BUFFER_BARRIER_BIT 0x00004000 IP Status No known IP claims. Additions to Chapter 2 of the OpenGL Core Profile Specification, Version 4.3, "OpenGL Fundamentals" Insert before the last line of Section 2.5.2, "Buffer Objects", p. 26: Under certain circumstances, the data store of a buffer object may be shared between the client and server and accessed simultaneously by both. Additions to Chapter 6 of the OpenGL Core Profile Specification, Version 4.3, "Buffer Objects" Modify Section 6.2, "Creating and Modifying Buffer Object Data Stores", p. 57 as follows: The data store of a buffer object is created by calling void BufferStorage(enum target, sizeiptr size, const void * data, bitfield flags); with set to one of the targets listed in Table 6.1, set to the size of the data store in basic machine units and containing a bit-field describing the intended usage of the data store. The data store of the buffer object bound to is allocated as a result of a call to this function and cannot be de-allocated until the buffer is deleted with a call to DeleteBuffers. Such a store may not be re-allocated through further calls to BufferStorage or BufferData. specifies the address in client memory of the data that should be used to initialize the buffer's data store. If is NULL, the data store of the buffer is created, but contains undefined data. Otherwise, should point to an array of at least basic machine units. is the bitwise OR of flags describing the intended usage of the buffer object's data store by the application. Valid flags and their meanings are as follows: DYNAMIC_STORAGE_BIT The contents of the data store may be updated after creation through calls to BufferSubData. If this bit is not set, the buffer content may not be directly updated by the client. The argument may be used to specify the initial content of the buffer's data store regardless of the presence of the DYNAMIC_STORAGE_BIT. Regardless of the presence of this bit, buffers may always be updated with server-side calls such as CopyBufferSubData and ClearBufferSubData. MAP_READ_BIT The buffer's data store may be mapped by the client for read access and a pointer in the client's address space obtained that may be read from. MAP_WRITE_BIT The buffer's data store may be mapped by the client for write access and a pointer in the client's address space obtained that may be written to. MAP_PERSISTENT_BIT The client may request that the server read from or write to the buffer while it is mapped. The client's pointer to the data store remains valid so long as the data store is mapped, even during execution of drawing or dispatch commands. MAP_COHERENT_BIT Shared access to buffers that are simultaneously mapped for client access and are used by the server will be coherent, so long as that mapping is performed using MapBufferRange. That is, data written to the store by either the client or server will be immediately visible to the other with no further action taken by the application. In particular: - If MAP_COHERENT_BIT is not set and the client performs a write followed by a call to one of the FlushMapped*BufferRange commands with a range including the written range, then in subsequent commands the server will see the writes. - If MAP_COHERENT_BIT is set and the client performs a write, then in subsequent commands the server will see the writes. - If MAP_COHERENT_BIT is not set and the server performs a write, the application must call MemoryBarrier with the CLIENT_MAPPED_BUFFER_BARRIER_BIT set and then call FenceSync with SYNC_GPU_COMMANDS_COMPLETE (or Finish). Then the CPU will see the writes after the sync is complete. - If MAP_COHERENT_BIT is set and the server does a write, the app must call FenceSync with SYNC_GPU_COMMANDS_COMPLETE (or Finish). Then the CPU will see the writes after the sync is complete. CLIENT_STORAGE_BIT When all other criteria for the buffer storage allocation are met, this bit may be used by an implementation to determine whether to use storage that is local to the server or to the client to serve as the backing store for the buffer. If contains MAP_PERSISTENT_BIT, it must also contain at least one of MAP_READ_BIT or MAP_WRITE_BIT. It is an error to specify MAP_COHERENT_BIT without also specifying MAP_PERSISTENT_BIT. BufferStorage deletes any existing data store, and sets the values of the buffer object's state variables as shown in table 6.3. If any portion of the buffer object is mapped in the current context or any context current to another thread, it is as though UnmapBuffer (see section 6.3.1) is executed in each such context prior to deleting the existing data store. Name | Value for | Value for | BufferData | BufferStorage -------------------------+-----------------------+--------------- BUFFER_SIZE | | BUFFER_USAGE | | DYNAMIC_DRAW BUFFER_ACCESS | READ_WRITE | READ_WRITE BUFFER_ACCESS_FLAGS | 0 | 0 BUFFER_IMMUTABLE_STORAGE | FALSE | TRUE BUFFER_MAPPED | FALSE | FALSE BUFFER_MAP_POINTER | NULL | NULL BUFFER_MAP_OFFSET | 0 | 0 BUFFER_MAP_LENGTH | 0 | 0 BUFFER_STORAGE_FLAGS | MAP_READ_BIT | | | MAP_WRITE_BIT | | | DYNAMIC_STORAGE_BIT | Table 6.3: Buffer object state after calling BufferData or BufferStorage. A mutable data store may be allocated for a buffer object by calling void BufferData(...) . Calling BufferData is equivalent to calling BufferStorage with , and as specified, and set to the logical OR of DYNAMIC_STORAGE_BIT, MAP_READ_BIT and MAP_WRITE_BIT. The GL will use the value of parameter to BufferData as a hint to further determine the intended use of the buffer. However, BufferStorage allocates immutable storage whereas BufferData allocates mutable storage. Thus, when a buffer's data store is allocated through a call to BufferData, the buffer's BUFFER_IMMUTABLE_STORAGE flags is set to FALSE. Add the following errors: An INVALID_OPERATION error is generated by BufferData and BufferStorage if the BUFFER_IMMUTABLE_STORAGE flag of the buffer bound to is set to TRUE. An INVALID_OPERATION error is generated by BufferSubData if the BUFFER_IMMUTABLE_STORAGE flag of the buffer bound to is TRUE and the value of BUFFER_STORAGE_FLAGS for the buffer does not have the DYNAMIC_STORAGE_BIT set. The command: void NamedBufferStorageEXT(uint buffer, sizeiptr size, const void * data, bitfield flags); behaves similarly to BufferStorage, except that the buffer whose storage is to be defined is specified by rather than by the current binding to . Add the following error: An INVALID_OPERATION error is generated by NamedBufferStorageEXT if the BUFFER_IMMUTABLE_STORAGE flag of is set to TRUE. Append to Table 6.2, "Buffer object parameters and their values": +---------------------------+---------+-----------+------------------+ | | | Initial | Legal | | Name | Type | Value | Values | +---------------------------+---------+-----------+------------------+ | BUFFER_IMMUTABLE_STORAGE | boolean | FALSE | TRUE, FALSE | | BUFFER_STORAGE_FLAGS | int | 0 | See section 6.2 | +---------------------------+---------+-----------+------------------+ Append to Table 6.3, "Buffer object initial state": +---------------------------+-------------------------------------- + | Name | Value | +---------------------------+---------------------------------------+ | BUFFER_IMMUTABLE_STORAGE | TRUE if the buffer's storage is | | | immutable, FALSE otherwise | | BUFFER_STORAGE_FLAGS | 0 | +---------------------------+---------------------------------------+ Modify Section 6.3, "Mapping and Unmapping Buffer Data" Add to the bulleted list describing flags that modify buffer mappings, p.62. * MAP_PERSISTENT_BIT indicates that it is not an error for the GL to read data from or write data to the buffer while it is mapped (see section 6.3.2). If this bit is set, the value of BUFFER_STORAGE_FLAGS for the buffer being mapped must include MAP_PERSISTENT_BIT. * MAP_COHERENT_BIT indicates that the mapping should be performed coherently. That is, such a mapping follows the rules set forth in section 6.2, "Creating and Modifying Buffer Object Data Stores". If the MAP_COHERENT_BIT is set and the buffer's BUFFER_STORAGE_FLAGS does not include MAP_COHERENT_BIT, the error INVALID_OPERATION is generated. Modify Section 6.3.2, "Effects of Mapping Buffers on Other GL Commands" to read: An INVALID_OPERATION error is generated by most, but not all GL commands when an attempt is detected by such a command to read data from or write data to a mapped buffer object unless it was allocated with the by a call to BufferStorage with MAP_PERSISTENT_BIT set in . Any command which does not detect these attempts, and performs such an invalid read or write, has undefined results and may result in GL interruption or termination. Add the following to the description of FlushMappedBufferRange: If a buffer range is mapped with both the MAP_PERSISTENT_BIT and MAP_FLUSH_EXPLICIT_BIT set, then FlushMappedBufferRange may be called to ensure that data written by the client into the flushed region becomes visible to the server. Data written to a coherent store will always become visible to the server after an unspecified period of time. Modify Section 6.8, "Buffer Object State", p. 70: Add the following required state to a buffer object: ..., a boolean indicating whether or not buffer storage is immutable, an unsigned integer storing the flags with which it was allocated, ... Additions to Chapter 7 of the OpenGL Core Profile Specification, Version 4.3, "Programs and Shaders" Add to the list of flags accepted by the parameter to MemoryBarrier in Section 7.12.2, "Shader Memory Access Synchronization": * CLIENT_MAPPED_BUFFER_BARRIER_BIT: Access by the client to persistent mapped regions of buffer objects will reflect data written by shaders prior to the barrier. Note that this may cause additional synchronization operations. New State Append to Table 23.6, "Buffer Object State", p. 511: +---------------------------+-----------+----------------------+-------------------+---------------------------------+------------+ | Get Value | Type | Get Command | Initial Value | Description | Sec. | +---------------------------+-----------+----------------------+-------------------+---------------------------------+------------+ | BUFFER_IMMUTABLE_STORAGE | B | GetBufferParameteriv | FALSE | TRUE if buffer's data store is | 6 | | | | | | immutable, FALSE otherwise | | | BUFFER_STORAGE_FLAGS | Z+ | GetBufferParameteriv | 0 | The buffer object's storage | 6 | | | | | | flags. | | +---------------------------+-----------+----------------------+-------------------+---------------------------------+------------+ New Implementation Dependent State None. Errors INVALID_OPERATION is generated by BufferStorage if zero is bound to . INVALID_OPERATION is generated by BufferStorage, NamedBufferStorageEXT and BufferData if the buffer object already owns an immutable data store. INVALID_VALUE is generated by BufferStorage and NamedBufferStorageEXT if is less than or equal to zero. INVALID_VALUE is generated by BufferStorage and NamedBufferStorageEXT if contains MAP_PERSISTENT_BIT but does not contain at least one of MAP_READ_BIT or MAP_WRITE_BIT. INVALID_VALUE is generated by BufferStorage and NamedBufferStorageEXT if contains MAP_COHERENT_BIT, but does not also contain MAP_PERSISTENT_BIT. INVALID_OPERATION is generated by MapBufferRange if any of MAP_READ_BIT, MAP_WRITE_BIT, MAP_PERSISTENT_BIT, or MAP_COHERENT_BIT are included in , but the same bit is not included in the buffer's storage flags. INVALID_OPERATION is generated by MapBufferRange if MAP_PERSISTENT_BIT is included in but MAP_PERSISTENT_BIT is not included in the buffer's storage flags, or if MAP_COHERENT_BIT is included in but MAP_COHERENT_BIT is not included in the buffer's storage flags. OUT_OF_MEMORY is generated by BufferStorage and NamedBufferStorageEXT if the GL is not able to allocate a data store with the properties requested in . *REMOVE* all errors generated by any command should they detect access to a mapped buffer and replace with language such as: INVALID_OPERATION is generated by if the buffer is currently mapped by MapBuffer{Range} unless it was mapped with the MAP_PERSISTENT_BIT included in . Dependencies on GL_EXT_direct_state_access If GL_EXT_direct_state_access is not supported, remove all references to NamedBufferStorageEXT. Conformance Tests TBD Usage Examples Example 1: Updating the content of a buffer which does not have the DYNAMIC flag set: // Allocate two buffers, one of which will be our 'staging buffer'. GLuint bufs[2]; glGenBuffers(2, &bufs[0]); // Client can map this buffer for write. // One could possibly make this mapping persistent. glBindBuffer(GL_COPY_READ_BUFFER, bufs[0]); glBufferStorage(GL_COPY_READ_BUFFER, size, NULL, GL_MAP_WRITE_BIT); // Client cannot read or write this buffer, server can do both. glBindBuffer(GL_COPY_WRITE_BUFFER, bufs[1]); glBufferStorage(GL_COPY_WRITE_BUFFER, size, NULL, 0); // Now, map the staging buffer to put data into it. void * data = glMapBufferRange(GL_COPY_READ_BUFFER, 0, size, GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_BUFFER_BIT); memcpy(data, source_data, size); glUnmapBuffer(GL_COPY_READ_BUFFER); // Copy from the staging buffer to the server-side buffer. glCopyBufferSubData(GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, 0, 0, size); Example 2: Read from framebuffer into a buffer mapped into client's address space: // Create buffer, allocate storage, and create a persistent map. GLuint pbo; glGenBuffers(1, &pbo); glBindBuffer(GL_PIXEL_PACK_BUFFER, pbo); glBufferStorage(GL_PIXEL_PACK_BUFFER, size, NULL, GL_MAP_READ_BIT | GL_MAP_PERSISTENT_BIT); void * data = glMapBufferRange(GL_PIXEL_PACK_BUFFER, GL_MAP_READ_BIT | GL_MAP_PERSISTENT_BIT); glReadPixels(0, 0, width, height, format, type, NULL); glMemoryBarrier(GL_CLIENT_MAPPED_BUFFER_BARRIER_BIT); GLsync fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0); // Do stuff to use time... ReallyExpensiveFunction(); glClientWaitSync(fence); // Use the data written to the buffer UseDataInMemory(data); XXX TODO::: MORE EXAMPLES HERE Issues 1) What is the best strategy to allow 'render while mapped'? Options I can think of right now are (a) Allow the application to render when a buffer is mapped, so long as the MAP_PERSISTENT_BIT was set when it was allocated; (b) Continue to disallow 'render while mapped', but say that a client pointer obtained from MapBuffer{Range} remains valid even when the buffer is not mapped, so long as it has not been destroyed; (c) add a flag to glMapBufferRange's parameter to indicate the desire to render with it. RESOLVED: We choose a combination of (a) and (c). The application must both create the data store with MAP_PERSISTENT_BIT set _and_ map it with MAP_PERSISTENT_BIT set in . Did the same for coherency too. 2) The new flags don't directly map to the parameter for glBufferData and one cannot be expressed in terms of the other. Does that matter? RESOLVED: Most applications get wrong and they're only hints anyway. The flags are hard and fast rules that must be followed. They serve a different purpose. The idea here is to allow the implementation to not have to second guess the application and to perform less tracking, and for the application to have more control. We define BufferData in terms of BufferStorage with the most liberal allowed flags (essentially, anything goes), but still pass the hint to the implementation to allow it to continue to second guess the application. 3) Do we have all the flags we want? Are any problematic? RESOLVED: We don't want any more flags. We don't believe any are problematic. 4) Should we include MULTI_TARGET_BIT? There are legitimate use cases where a buffer could be used on two or three targets. However, this bit is an 'all or nothing' kind of thing. RESOLVED: No, not at this time. 5) How do you get data into a non-dynamic buffer if you can't write to it from the client? RESOLVED: The server is capable of writing to buffers that were not allocated with the DYNAMIC flag set. Therefore, it is possible to use CopyBufferSubData to copy from a dynamic buffer to a non-dynamic buffer. It's also possible to write to it with any other server-side mechanism such as transform feedback, image stores and so on. 6) If a buffer is allocated without the GL_BUFFER_STORAGE_SERVER_READ_BIT (or GL_BUFFER_STORAGE_SERVER_WRITE_BIT), what happens if an attempt is made use the buffer in a way that may cause the server to read (or write) to the buffer? RESOLVED: Nuked the SERVER_READ and SERVER_WRITE bits. They didn't serve the purpose for which they were intended. 7) Which operations are able to update buffers that are not dynamic? Non-dynamic buffers effectively don't allow direct transfer of data from client to server (i.e., glBufferSubData). Examples of operations that may write to non-dynamic buffers are transform feedback, image stores, ReadPixels, GetTexImage (PBO), CopyBufferSubData, ClearBufferSubData - essentially anything that doesn't transfer arbitrary amounts of data from client to server. 8) Are there any restrictions on calling GetBufferSubData on a buffer allocated using BufferStorage? RESOLVED: No, there are not. 9) What is the meaning of CLIENT_STORAGE_BIT? Is it one of those silly hint things? DISCUSSION: Unfortunately, yes, it is. For some platforms, such as UMA systems, it's irrelevant and all memory is both server and client accessible. The issue is, that on some platforms and for certain combinations of flags, there may be multiple regions of memory that can satisfy the request (visible to both server and client and coherent to both, for example), but may have substantially different performance characteristics for access from either. This bit essentially serves as a hint to say that that an application will access the store more frequently from the client than from the server. In practice, applications will still get it wrong (like setting it all the time or never setting it at all, for example), implementations will still have to second guess applications and end up full of heuristics to figure out where to put data and gobs of code to move things around based on what applications do, and eventually it'll make no difference whether applications set it or not. But hey, we tried. 10) Do we want to add flags for MapBufferRange for PERSISTENT and/or COHERENT mapping? In their absence, implementations must assume that any mapping performed on a buffer whose storage flags include the PERSISTENT or COHERENT flags must behave appropriately. RESOLVED. Added. 11) Do we need language to explicitly say that flushes of non-coherent mapped buffers need to occur on buffers mapped with the FLUSH_EXPLICIT bit? RESOLVED: No. The language already states that FlushMappedBufferRange should be used to perform the flush, and this command requires that the mapping be established with the FLUSH_EXPLICIT bit set. 12) Which functions can/cannot be used to update the content of a non-DYNAMIC buffer? Can the buffer be the target of an update operation at all? RESOLVED: BufferSubData is only allowed for DYNAMIC buffers. Updates through mappings are allowed so long as the STORAGE_MAP_WRITE_BIT is set. Server side commands, including CopyBufferSubData, ClearBufferSubData, ReadPixels, GetTexImage are allowed. Further, shader writes such as image stores, SSBO, atomic counters, transform feedback and so on are also allowed. 13) Why is there a gap between the MAP_WRITE_BIT and MAP_PERSISTENT_BIT token values? RESOLVED: MAP_PERSISTENT_BIT and MAP_COHERENT_BIT are allocated from the bitfield used for MapBufferRange, which include values that aren't relevant for BufferStorage. This allows the same tokens to be used as flags for BufferStorage and MapBufferRange, hopefully reducing confusion. Revision History Rev. Date Author Changes ---- -------- -------- ----------------------------------------- 1 01/16/2013 gsellers Initial draft 2 01/21/2013 gsellers Updates 3 01/22/2013 gsellers Change static->dynamic. Remove target restrictions. Get a little closer to expressing BufferData in terms of BufferStorage. 4 04/22/2013 gsellers Add CLIENT_MAPPED_BUFFER_ACCESS_BIT for MemoryBarrier. Add BUFFER_STORAGE_{READ|WRITE}_BIT and issue 6. Add example usage for non-dynamic buffers. Add issue 7. 5 04/23/2013 gsellers Nuked the BUFFER_STORAGE_{READ|WRITE}_BIT flags again. Make DYNAMIC and MAP_WRITE_BIT orthogonal. Rename CLIENT_MAPPED_BUFFER_ACCESS_BIT to CLIENT_MAPPED_BUFFER_BARRIER_BIT. Add another example. Update values of tokens. Add (and resolve) issue 8. 6 05/14/2013 gsellers Add BUFFER_STORAGE_SERVER_BIT. Define value of for buffers allocated with BufferStorage. Issue 9. 7 05/22/2013 gsellers Address several issues from bug 10246. 8 05/23/2013 gsellers Address issues from bug 10288. * Change BUFFER_STORAGE_SERVER_BIT to CLIENT_STORAGE_BIT (inverting its sense), which makes 0 'fast'. * Clarify that DYNAMIC_BIT only affects BufferSubData (i.e., direct, arbitrary client->server transfers). * Add issues 11 + 12. 9 05/28/2013 Jon Leech Fix various typos resulting from changes in token names, tweak language to match API spec, some paragraph reflowing, insert some questions marked by '**' inline. 10 05/29/2013 gsellers Remove parameter from NamedBufferStorageEXT. Incorporate new rules for coherency. Add COHERENT_MAP_BIT for MapBufferRange. 11 05/30/2013 Jon Leech Fix typos including COHERENT_MAP_BIT -> MAP_COHERENT_BIT and PERSISTENT_MAP_BIT -> MAP_PERSISTENT_BIT. 12 05/30/2013 gsellers Resolve issues 3 and 10. Fix typos. Resolve issues from bug 10326. Add (and resolve) issue 13. 13 05/30/2013 gsellers Change names of flags (again). Use same values for MapBufferRange flags and BufferStorage flags. 14 05/30/2013 Jon Leech Clean up language describing flags and some indentation issues. 15 05/31/2013 Jon Leech Add BUFFER_IMMUTABLE_STORAGE to table 6.2 (Bug 10288). 16 06/06/2013 Jon Leech Change default BUFFER_IMMUTABLE_STORAGE value in table 6.2 to FALSE, matching API spec, since these are values when created with BindBuffer. Fix typo from bug 10326. 17 06/27/2013 Jon Leech Add error for BufferSubData and fix example code (Bug 10326) 18 07/03/2013 gsellers Fix language describing DYNAMIC_STORAGE_BIT (mutated -> updated), and typo in description of usage parameter when storage is allocated with BufferStorage. (Bug 10471) 19 07/18/2013 gsellers Added missing values for MAP_PERSISTENT_BIT and MAP_COHERENT_BIT. 20 07/18/2013 Jon Leech Add BufferStorage initial state to table 6.3 and add error when zero is bound to (Bug 10335). 21 07/19/2013 Jon Leech Clean up table 6.3 captions to match API spec (Bug 10335). 22 08/15/2013 Jon Leech Remove error for BufferStorage and NamedBufferStorageEXT if contains MAP_WRITE_BIT but does not contain DYNAMIC_STORAGE_BIT (Bug 10561, public Bug 925). 23 08/16/2013 mjk Better indicate DSA entrypoints 24 06/09/2014 Jon Leech Change query commands for buffer storage state to GetBufferParameteriv (Bug 12307). 25 04/20/2015 Jon Leech Change description of MAP_COHERENT_BIT for buffer storage so that barriers with CLIENT_MAPPED_BUFFER_BARRIER_BIT do not need to make CPU writes visible to the GPU in this case without an explicit flush (Bug 13578).