| Name |
| |
| ARB_texture_buffer_range |
| |
| Name Strings |
| |
| GL_ARB_texture_buffer_range |
| |
| Contact |
| |
| Graham Sellers (graham.sellers 'at' amd.com) |
| |
| Contributors |
| |
| Jon Leech |
| Mark Kilgard, NVIDIA |
| |
| Notice |
| |
| Copyright (c) 2012-2013 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 2012/06/12. |
| |
| Version |
| |
| Last Modified Date: August 7, 2013 |
| Version: 8 |
| |
| Number |
| |
| ARB Extension #139 |
| |
| Dependencies |
| |
| ARB_texture_buffer_object or OpenGL 3.1 is required. |
| |
| The definition of this extension is dependent on EXT_direct_state_access. |
| |
| This extension is written against the OpenGL 4.2 (Core) Specification. |
| |
| Overview |
| |
| ARB_texture_buffer_object (which was promoted to core in OpenGL 3.1) |
| introduced the ability to attach the data store of a buffer object |
| to a buffer texture and access it from shaders. The extension only allows |
| the entire store of the buffer object to the texture. This extension |
| expands on this and allows a sub-range of the buffer's data store to |
| be attached to a texture. This can be used, for example, to allow multiple |
| buffer textures to be backed by independent sub-ranges of the same buffer |
| object, or for different sub-ranges of a single buffer object to be used |
| for different purposes. |
| |
| IP Status |
| |
| No known IP claims. |
| |
| New Procedures and Functions |
| |
| void TexBufferRange(enum target, |
| enum internalformat, |
| uint buffer, |
| intptr offset, |
| sizeiptr size); |
| |
| When EXT_direct_state_access is present: |
| |
| void TextureBufferRangeEXT(uint texture, |
| enum target, |
| enum internalformat, |
| uint buffer, |
| intptr offset, |
| sizeiptr size); |
| |
| New Tokens |
| |
| Accepted by the <pname> parameter of GetTexLevelParameter: |
| |
| TEXTURE_BUFFER_OFFSET 0x919D |
| TEXTURE_BUFFER_SIZE 0x919E |
| |
| Accepted by the <pname> parameter of GetBooleanv, GetIntegerv, GetFloatv, |
| and GetDoublev: |
| |
| TEXTURE_BUFFER_OFFSET_ALIGNMENT 0x919F |
| |
| Additions to Chapter 2 of the OpenGL 4.2 (Core Profile) Specification |
| (OpenGL Operation) |
| |
| None. |
| |
| Additions to Chapter 3 of the OpenGL 4.2 (Core Profile) Specification |
| (Rasterization) |
| |
| Modifications to Section 3.8.7 "Buffer Textures" |
| |
| Change the description of TexBuffer as follows: |
| |
| The command |
| |
| void TexBufferRange(enum target, |
| enum internalformat, |
| uint buffer, |
| intptr offset, |
| sizeiptr size); |
| |
| attaches the range of the storage for the buffer object named <buffer> |
| for <size> basic machine units, starting at <offset> (also in basic machine |
| units) to the active buffer texture, and specifies an internal format |
| for the texel array found in the range of the attached buffer object. If |
| <buffer> is zero, then any buffer object attached to the buffer texture |
| is detached, the values <offset> and <size> are ignored and the state for |
| <offset> and <size> for the buffer texture are reset to zero. If <buffer> |
| is non-zero, but is not the name of a buffer object, the error |
| INVALID_OPERATION is generated. If <offset> is negative or if <size> is |
| less than or equal to zero or if <offset> + <size> is greater than the |
| value of BUFFER_SIZE for the buffer bound to <target>, of if <offset> is |
| not an integer multiple of TEXTURE_BUFFER_OFFSET_ALIGNMENT, then the error |
| INVALID_VALUE is generated. <internalformat> specifies the storage format |
| and must be one of the sized internal formats found in Table 3.15. |
| |
| The command |
| |
| void TextureBufferRangeEXT(uint texture, |
| enum target, |
| enum internalformat, |
| uint buffer, |
| intptr offset, |
| sizeiptr size); |
| |
| behaves identically to TexBufferRange, except rather than updating the |
| currently bound texture object for the texture unit indicated by the current |
| active texture state, the texture object named <texture> is updated |
| directly. <texture> must be a name returned from a previous call to |
| GenTextures or be that of an existing texture matching <target>. If <texture> |
| is not the name of an existing texture, one is created with the name |
| <texture> for <target>. |
| |
| The command |
| |
| void TexBuffer(enum target, |
| enum internalformat, |
| uint buffer); |
| |
| is equivalent to calling TexBufferRange with the <target>, <internalformat> |
| and <buffer> parameters as specified, with <offset> set to zero, and |
| <size> set to the value of BUFFER_SIZE for <buffer>. |
| |
| When a range of the storage of a buffer object is attached to a buffer |
| texture, the range of the buffer's data store is taken as the texture's |
| texel array. The number of texels in the buffer texture's texel array is |
| given by |
| |
| | <size> | |
| | ------------------------------------ | |
| |_ <components> x sizeof(<base_type>) _| |
| |
| where <components> and <base_type> are the element count and base type for |
| elements, as specified in Table 3.15. |
| |
| Modifications to Section 3.9.15 "Texture and Proxy State" |
| |
| Add to the state required for buffer textures: |
| |
| ... The buffer texture target has associated an integer containing the name |
| of the buffer object that provided the data store for the texture, |
| initially zero, and two pointer sized integers containing the offset and |
| range of the buffer object's data store, also initially zero. |
| |
| Additions to Chapter 4 of the OpenGL 4.2 (Core Profile) Specification |
| (Per-Fragment Operations and the Frame Buffer) |
| |
| None. |
| |
| Additions to Chapter 5 of the OpenGL 4.2 (Core Profile) Specification |
| (Special Functions) |
| |
| None. |
| |
| Additions to Chapter 6 of the OpenGL 4.2 (Core Profile) Specification |
| (State and State Requests) |
| |
| None. |
| |
| Errors |
| |
| INVALID_ENUM is generated by TexBufferRange if <target> is not |
| TEXTURE_BUFFER. |
| |
| INVALID_VALUE is generated by TexBufferRange if <offset> is less than zero. |
| |
| INVALID_VALUE is generated by TexBufferRange if <size> is less than zero. |
| |
| INVALID_VALUE is generated by TexBufferRange if <offset> + <size> is |
| greater than the value of BUFFER_SIZE for <buffer>. |
| |
| INVALID_VALUE is generated by TexBufferRange if <offset> is not |
| an integer multiple of the value of TEXTURE_BUFFER_OFFSET_ALIGNMENT. |
| |
| New State |
| |
| Append to Table 6.17. Textures (state per texture image) |
| |
| +-------------------------+---------+----------------------+---------------+------------------------------------------+ |
| | Get Value | Type | Get Command | Initial Value | Description | |
| +-------------------------+---------+----------------------+---------------+------------------------------------------+ |
| | TEXTURE_BUFFER_OFFSET | n x Z | GetTexLevelParameter | 0 | Offset into buffer's data store used for | |
| | | | | | the active image unit's buffer texture | |
| | TEXTURE_BUFFER_SIZE | n x Z | GetTexLevelParameter | 0 | Size of the buffer's data store used for | |
| | | | | | the active image unit's buffer texture | |
| +-------------------------+---------+----------------------+---------------+------------------------------------------+ |
| |
| New Implementation Dependent State |
| |
| +---------------------------------+------+-------------+------------+----------------------------+---------+-----------+ |
| | | | | Minimum | | | | |
| | Get Value | Type | Get Command | Value | Description | Sec | Attribute | |
| +---------------------------------+------+-------------+------------+----------------------------+---------+-----------+ |
| | TEXTURE_BUFFER_OFFSET_ALIGNMENT | Z+ | GetIntegerv | 1 | Minimum required alignment | 3.8.7 | - | |
| | | | | | for texture buffer offsets | | | |
| +---------------------------------+------+-------------+------------+----------------------------+---------+-----------+ |
| |
| Conformance Tests |
| |
| TBD |
| |
| Issues |
| |
| 1) Do we need to have restrictions on the alignment of <offset> and/or |
| <size> for TexBufferRange? |
| |
| RESOLVED: Yes for offset, no for range. The minimum value here is 1, |
| essentially making it optional for offsets. |
| |
| Dependencies on EXT_direct_state_access |
| |
| If EXT_direct_state_access is not supported, remove all references to |
| TextureBufferRangeEXT. |
| |
| Revision History |
| |
| Rev. Date Author Changes |
| ---- ---------- -------- ----------------------------------------- |
| 8 08/07/2013 mjk Better indicate DSA entrypoints |
| 7 05/29/2012 Jon Leech Fix capitalization of <internalformat>. |
| 6 05/02/2012 drakos Add EXT suffix to TextureBufferRange. |
| 5 04/30/2012 gsellers Assign token values. |
| Add more error behavior. |
| Minor fixes. |
| 4 04/26/2012 gsellers Clarify that <offset> and <size> are reset for |
| TexBOs when a buffer is unbound. |
| 3 04/02/2012 gsellers Update token names. Correct typos. (bug 8131). |
| Add TEXTURE_BUFFER_OFFSET_ALIGNMENT. |
| Resolve issue (1). |
| 2 12/19/2011 gsellers Document interaction with EXT_dsa. Rename to |
| ARB. Remove ARB suffixes from APIs and tokens. |
| 1 09/26/2011 gsellers Initial draft |
