| Name |
| |
| EXT_shader_integer_mix |
| |
| Name Strings |
| |
| GL_EXT_shader_integer_mix |
| |
| Contact |
| |
| Matt Turner (matt.turner 'at' intel.com) |
| |
| Contributors |
| |
| Matt Turner, Intel |
| Ian Romanick, Intel |
| |
| Status |
| |
| Shipping |
| |
| Version |
| |
| Last Modified Date: 09/12/2013 |
| Author Revision: 6 |
| |
| Number |
| |
| TBD |
| |
| Dependencies |
| |
| OpenGL 3.0 or OpenGL ES 3.0 is required. This extension interacts with |
| GL_ARB_ES3_compatibility. |
| |
| This extension is written against the OpenGL 4.4 (core) specification |
| and the GLSL 4.40 specification. |
| |
| Overview |
| |
| GLSL 1.30 (and GLSL ES 3.00) expanded the mix() built-in function to |
| operate on a boolean third argument that does not interpolate but |
| selects. This extension extends mix() to select between int, uint, |
| and bool components. |
| |
| New Procedures and Functions |
| |
| None. |
| |
| New Tokens |
| |
| None. |
| |
| Additions to Chapter 8 of the GLSL 4.40 Specification (Built-in Functions) |
| |
| Modify Section 8.3, Common Functions |
| |
| Additions to the table listing common built-in functions: |
| |
| Syntax Description |
| --------------------------- -------------------------------------------------- |
| genIType mix(genIType x, Selects which vector each returned component comes |
| genIType y, from. For a component of a that is false, the |
| genBType a) corresponding component of x is returned. For a |
| genUType mix(genUType x, component of a that is true, the corresponding |
| genUType y, component of y is returned. |
| genBType a) |
| genBType mix(genBType x, |
| genBType y, |
| genBType a) |
| |
| Additions to the AGL/GLX/WGL Specifications |
| |
| None. |
| |
| Modifications to The OpenGL Shading Language Specification, Version 4.40 |
| |
| Including the following line in a shader can be used to control the |
| language features described in this extension: |
| |
| #extension GL_EXT_shader_integer_mix : <behavior> |
| |
| where <behavior> is as specified in section 3.3. |
| |
| New preprocessor #defines are added to the OpenGL Shading Language: |
| |
| #define GL_EXT_shader_integer_mix 1 |
| |
| Interactions with ARB_ES3_compatibility |
| |
| On desktop implementations that support ARB_ES3_compatibility, |
| GL_EXT_shader_integer_mix can be enabled (and the new functions |
| used) in shaders declared with '#version 300 es'. |
| |
| GLX Protocol |
| |
| None. |
| |
| Errors |
| |
| None. |
| |
| New State |
| |
| None. |
| |
| New Implementation Dependent State |
| |
| None. |
| |
| Issues |
| |
| 1) Should we allow linear interpolation of integers via a non-boolean |
| third component? |
| |
| RESOLVED: No. |
| |
| 2) Should we allow mix() to select between boolean components? |
| |
| RESOLVED: Yes. Implementing the same functionality using casts would be |
| possible but ugly. |
| |
| Revision History |
| |
| Rev. Date Author Changes |
| ---- -------- -------- --------------------------------------------- |
| 6 09/12/2013 idr After discussions in Khronos, change vendor |
| prefix to EXT. |
| |
| 5 09/09/2013 idr Add ARB_ES3_compatibility interaction. |
| |
| 4 09/06/2013 mattst88 Allow extension on OpenGL ES 3.0. |
| |
| 3 08/28/2013 mattst88 Add #extension/#define changes. |
| |
| 2 08/26/2013 mattst88 Change vendor prefix to MESA. Add mix() that |
| selects between boolean components. |
| 1 08/26/2013 mattst88 Initial revision |
