glGetProgramResourceLocationIndex - query the fragment color index of a named variable within a program

GLintglGetProgramResourceLocationIndex(GLuintprogram,GLenumprogramInterface,constchar*name);

       Copyright © 2013-2014 Khronos Group

[FIXME: source]                                    11/18/2024                           GLGETPROGRAMRESOURCE(3G)

glGetProgramResourceLocationIndex returns the fragment color index assigned to the variable named name in
       interface programInterface of program object program.  program must be the name of a program that has
       been linked successfully.  programInterface must be GL_PROGRAM_OUTPUT.

       The value -1 will be returned if an error occurs, if name does not identify an active variable on
       programInterface, or if name identifies an active variable that does not have a valid location assigned,
       as described above. The locations returned by these commands are the same locations returned when
       querying the GL_LOCATION and GL_LOCATION_INDEX resource properties.

       A string provided to glGetProgramResourceLocationIndex is considered to match an active variable if:

       •   the string exactly matches the name of the active variable

       •   if the string identifies the base name of an active array, where the string would exactly match the
           name of the variable if the suffix "[0]" were appended to the string

       •   if the string identifies an active element of the array, where the string ends with the concatenation
           of the "[" character, an integer withno"+"sign,extraleadingzeroes,orwhitespace identifying an
           array element, and the "]" character, the integer is less than the number of active elements of the
           array variable, and where the string would exactly match the enumerated name of the array if the
           decimal integer were replaced with zero.

       Any other string is considered not to identify an active variable. If the string specifies an element of
       an array variable, glGetProgramResourceLocation returns the location assigned to that element. If it
       specifies the base name of an array, it identifies the resources associated with the first element of the
       array.

GL_INVALID_VALUE is generated if program is not the name of an existing program object.

       GL_INVALID_ENUM is generated if programInterface is not one of the accepted interface types.

       GL_INVALID_OPERATION is generated if program has not been linked successfully.

       glGetProgramResourceLocationIndex - query the fragment color index of a named variable within a program

program
           The name of a program object whose resources to query.

       programInterface
           A token identifying the interface within program containing the resource named name.

       name
           The name of the resource to query the location of.

glGetProgramResourceName(), glGetProgramResourceIndex(), glGetProgramResource(),
       glGetProgramResourceLocationIndex().

       ┌───────────────────────────────────┬───────────────────────────────────────────────────────────────────────┐
       │                                   │                OpenGLVersion                                         │
       ├───────────────────────────────────┼─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┤
       │ Function                          │ 2.0 │ 2.1 │ 3.0 │ 3.1 │ 3.2 │ 3.3 │ 4.0 │ 4.1 │ 4.2 │ 4.3 │ 4.4 │ 4.5 │
       │ /                                 │     │     │     │     │     │     │     │     │     │     │     │     │
       │ Feature                           │     │     │     │     │     │     │     │     │     │     │     │     │
       │ Name                              │     │     │     │     │     │     │     │     │     │     │     │     │
       ├───────────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
       │ glGetProgramResourceLocationIndex │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  ✔  │  ✔  │  ✔  │
       └───────────────────────────────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘