blob: b5cd1bb8192ca0fcc3758570e51c7fee9497cad2 [file] [log] [blame]
Name Strings
Geoff Lang, (geofflang 'at'
Timothy Lottes, AMD
Graham Sellers, AMD
Eric Werness, NVIDIA
Geoff Lang, Google
Daniel Koch, NVIDIA
Copyright (c) 2015 The Khronos Group Inc. Copyright terms at
Specification Update Policy
Khronos-approved extension specifications are updated in response to
issues and bugs prioritized by the Khronos OpenGL and OpenGL ES Working Groups. 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
Last Modified Date: 2017-04-24
Revision: 2
ARB Extension #192
OpenGL ES Extension #288
This extension is written against OpenGL 4.5 (CoreProfile) dated
May 28 2015.
OpenGL ES 2.0 is required (for mobile).
Compiling GLSL into implementation-specific code can be a time consuming
process, so a GL implementation may wish to perform the compilation in a
separate CPU thread. This extension provides a mechanism for the application
to provide a hint to limit the number of threads it wants to be used to
compile shaders, as well as a query to determine if the compilation process
is complete.
New Procedures and Functions
void MaxShaderCompilerThreadsKHR(uint count);
New Tokens
Accepted by the <pname> parameter of GetBooleanv, GetIntegerv,
GetInteger64v, GetFloatv, and GetDoublev:
Accepted as part of the <pname> parameter to GetShaderiv and
accepted as part of the <pname> parameter to GetProgramiv:
IP Status
Additions to Chapter 7 "Programs and Shaders",
Append to the end of 7.1 "Shader Objects",
Applications may use the following to hint to the driver the maximum
number background threads it would like to be used in the process of
compiling shaders or linking programs,
void MaxShaderCompilerThreadsKHR(uint count);
where <count> is the number of background threads. A <count> of zero
specifies a request for no parallel compiling or linking and a <count> of
0xFFFFFFFF requests an implementation-specific maximum.
An implementation may combine the maximum compiler thread request from
multiple contexts in a share group in an implementation-specific way.
An application can query the current MaxShaderCompilerThreadsKHR <count>
by calling GetIntegerv with <pname> set to MAX_SHADER_COMPILER_THREADS_KHR,
which returns the value of the current state (Table 23.51).
Add to 7.13 "Shader, Program, and Program Pipeline Queries" under the
descriptions for "pname" for "GetShaderiv",
If <pname> is COMPLETION_STATUS_KHR, TRUE is returned if the shader
compilation has completed, FALSE otherwise.
Add to 7.13 "Shader, Program, and Program Pipeline Queries" under the
descriptions for "pname" for "GetProgramiv",
If <pname> is COMPLETION_STATUS_KHR, TRUE is returned if the program
linking has completed, FALSE otherwise.
New State
Add to Table 23.51: Hints
Get Value Type Get Command Initial Value Description Sec
------------------------------- ---- ------------ ------------- -------------------- ----
MAX_SHADER_COMPILER_THREADS_KHR Z+ GetIntegerv 0xFFFFFFFF Max compile threads 7.13
Add to Table 23.32: Program Object State
Get Value Type Get Command Initial Value Description Sec
---------------------- ---- ------------ ------------- -------------------- ----
COMPLETION_STATUS_KHR B GetProgramiv TRUE Program linking has 7.13
Add to Table 23.30: Shader Object State
Get Value Type Get Command Initial Value Description Sec
--------------------- ---- ------------ ------------- -------------------- ----
COMPLETION_STATUS_KHR B GetShaderiv TRUE Shader compilation 7.13
has completed
Interactions with OpenGL ES
If implemented in OpenGL ES ignore all references to GetDoublev.
If the supported ES version is less than 3.0, ignore all references to
1) Where should the hint state be stored?
UNRESOLVED: Each context has its own value which may be specified and
queried, but an implementation may choose to combine the hints from multiple
contexts in an implmentation-specific manner. There isn't really any
precedent for per-share group state.
2) Can we make the requirements more strict?
RESOLVED: We could, but making sure all of the error behavior is correct and
fully specified would likely take more time than we have. This spec allows
an application to clearly request its intent even if there aren't guarantees
that the implementation will exactly obey the request.
3) Does glGetIntegerv(MAX_SHADER_COMPILER_THREADS_KHR) just return the
value set by MaxShaderCompilerThreadsKHR? Or, if the state is 0xFFFFFFFF
("do something implementation specific"), does it return the number of
threads the implementation has actually chosen to use?
RESOLVED: As with other state queries, this returns the value that was last
set, or if no value was set by the application it returns the default state
value (0xFFFFFFFF).
Revision History
Rev Date Author Changes
--- ---------- -------- ---------------------------------------------
1 2017-03-23 glang Cast as KHR based on v6 of
2 2017-04-24 dgkoch Spec clarifications, add issue 3.