glGetUniformBlockIndex.3G - Man Page

retrieve the index of a named uniform block

C Specification

GLuint glGetUniformBlockIndex(GLuint program, const GLchar *uniformBlockName);

Parameters

program: Specifies the name of a program containing the uniform block.
uniformBlockName: Specifies the address an array of characters to containing the name of the uniform block whose index to retrieve.

Description

glGetUniformBlockIndex retrieves the index of a uniform block within program.

program must be the name of a program object for which the command glLinkProgram() must have been called in the past, although it is not required that glLinkProgram() must have succeeded. The link could have failed because the number of active uniforms exceeded the limit.

uniformBlockName must contain a nul-terminated string specifying the name of the uniform block.

glGetUniformBlockIndex returns the uniform block index for the uniform block named uniformBlockName of program. If uniformBlockName does not identify an active uniform block of program, glGetUniformBlockIndex returns the special identifier, GL_INVALID_INDEX. Indices of the active uniform blocks of a program are assigned in consecutive order, beginning with zero.

Errors

GL_INVALID_OPERATION is generated if program is not the name of a program object for which glLinkProgram() has been called in the past.

Notes

glGetUniformBlockIndex is available only if the GL version is 3.1 or greater.

Version Support

	OpenGL Version
Function / Feature Name	2.0	2.1	3.0	3.1	3.2	3.3	4.0	4.1	4.2	4.3	4.4	4.5
glGetUniformBlockIndex	-	-	-	✔	✔	✔	✔	✔	✔	✔	✔	✔