Gl.GetUniformLocation (gb.opengl.glsl)
Static Function GetUniformLocation ( Program As Integer, Name As String ) As Integer
Returns the location of a uniform variable.
Parameters
- program
-
Specifies the program object to be
queried.
- name
-
Points to a null terminated string containing
the name of the uniform variable whose location is
to be queried.
Description
Gl.GetUniformLocation * returns an
integer that represents the location of a specific uniform
variable within a program object.
name
must be a null terminated string that contains no white space.
name must be an active uniform variable
name in
program that is not a structure,
an array of structures, or a subcomponent of a vector or a
matrix. This function returns -1 if
name
does not correspond to an active uniform variable in
program or if
name
starts with the reserved prefix "gl_".
Uniform variables that are structures or arrays of
structures may be queried by calling
Gl.GetUniformLocation for each field within
the structure. The array element operator "[]" and the
structure field operator "." may be used in
name in order to select elements within
an array or fields within a structure. The result of using these
operators is not allowed to be another structure, an array of
structures, or a subcomponent of a vector or a matrix. Except if
the last part of
name indicates a uniform
variable array, the location of the first element of an array
can be retrieved by using the name of the array, or by using the
name appended by "
/edit/0".
The actual locations assigned to uniform variables are not
known until the program object is linked successfully. After
linking has occurred, the command
Gl.GetUniformLocation can be used to obtain
the location of a uniform variable. This location value can then
be passed to
Glu.niform
to set the value of the uniform variable or to
Gl.GetUniform
in order to query the current value of the uniform variable.
After a program object has been linked successfully, the index
values for uniform variables remain fixed until the next link
command occurs. Uniform variable locations and values can only
be queried after a link if the link was successful.
Errors
Gl.INVALID_VALUE is generated if
program is not a value generated by
OpenGL.
Gl.INVALID_OPERATION is generated if
program is not a program object.
Gl.INVALID_OPERATION is generated if
program has not been successfully
linked.
Associated Gets
Gl.GetActiveUniform
with arguments
program and the index of
an active uniform variable
Gl.GetProgram
with arguments
program and
Gl.ACTIVE_UNIFORMS or
Gl.ACTIVE_UNIFORM_MAX_LENGTH
Gl.GetUniform
with arguments
program and the name of a
uniform variable
Gl.IsProgram
See also
See original documentation on OpenGL website