glGetActiveUniformsiv — Returns information about several active uniform variables for the specified program object
void glGetActiveUniformsiv(  GLuint program, 
GLsizei uniformCount,  
const GLuint *uniformIndices,  
GLenum pname,  
GLint *params) ; 
program
Specifies the program object to be queried.
uniformCount
Specifies both the number of elements in the array of
indices uniformIndices
and the number of
parameters written to params
upon
successful return.
uniformIndices
Specifies the address of an array of
uniformCount
integers containing the
indices of uniforms within program
whose
parameter pname
should be queried.
pname
Specifies the property of each uniform in
uniformIndices
that should be written
into the corresponding element of
params
.
params
Specifies the address of an array of
uniformCount
integers which are to
receive the value of pname
for each
uniform in uniformIndices
.
glGetActiveUniformsiv
queries the value of
the parameter named pname
for each of the
uniforms within program
whose indices are
specified in the array of uniformCount
unsigned integers uniformIndices
. Upon
success, the value of the parameter for each uniform is written
into the corresponding entry in the array whose address is given
in params
. If an error is generated,
nothing is written into params
.
If pname
is
GL_UNIFORM_TYPE
, then an array identifying
the types of uniforms specified by the corresponding array of
uniformIndices
is returned. The returned
types can be any of the values from the following table:
Returned Symbolic Contant  Shader Uniform Type 

GL_FLOAT

float

GL_FLOAT_VEC2

vec2

GL_FLOAT_VEC3

vec3

GL_FLOAT_VEC4

vec4

GL_INT

int

GL_INT_VEC2

ivec2

GL_INT_VEC3

ivec3

GL_INT_VEC4

ivec4

GL_UNSIGNED_INT

unsigned int

GL_UNSIGNED_INT_VEC2

uvec2

GL_UNSIGNED_INT_VEC3

uvec3

GL_UNSIGNED_INT_VEC4

uvec4

GL_BOOL

bool

GL_BOOL_VEC2

bvec2

GL_BOOL_VEC3

bvec3

GL_BOOL_VEC4

bvec4

GL_FLOAT_MAT2

mat2

GL_FLOAT_MAT3

mat3

GL_FLOAT_MAT4

mat4

GL_FLOAT_MAT2x3

mat2x3

GL_FLOAT_MAT2x4

mat2x4

GL_FLOAT_MAT3x2

mat3x2

GL_FLOAT_MAT3x4

mat3x4

GL_FLOAT_MAT4x2

mat4x2

GL_FLOAT_MAT4x3

mat4x3

GL_SAMPLER_1D

sampler1D

GL_SAMPLER_2D

sampler2D

GL_SAMPLER_3D

sampler3D

GL_SAMPLER_CUBE

samplerCube

GL_SAMPLER_1D_SHADOW

sampler1DShadow

GL_SAMPLER_2D_SHADOW

sampler2DShadow

GL_SAMPLER_1D_ARRAY

sampler1DArray

GL_SAMPLER_2D_ARRAY

sampler2DArray

GL_SAMPLER_1D_ARRAY_SHADOW

sampler1DArrayShadow

GL_SAMPLER_2D_ARRAY_SHADOW

sampler2DArrayShadow

GL_SAMPLER_2D_MULTISAMPLE

sampler2DMS

GL_SAMPLER_2D_MULTISAMPLE_ARRAY

sampler2DMSArray

GL_SAMPLER_CUBE_SHADOW

samplerCubeShadow

GL_SAMPLER_BUFFER

samplerBuffer

GL_SAMPLER_2D_RECT

sampler2DRect

GL_SAMPLER_2D_RECT_SHADOW

sampler2DRectShadow

GL_INT_SAMPLER_1D

isampler1D

GL_INT_SAMPLER_2D

isampler2D

GL_INT_SAMPLER_3D

isampler3D

GL_INT_SAMPLER_CUBE

isamplerCube

GL_INT_SAMPLER_1D_ARRAY

isampler1DArray

GL_INT_SAMPLER_2D_ARRAY

isampler2DArray

GL_INT_SAMPLER_2D_MULTISAMPLE

isampler2DMS

GL_INT_SAMPLER_2D_MULTISAMPLE_ARRAY

isampler2DMSArray

GL_INT_SAMPLER_BUFFER

isamplerBuffer

GL_INT_SAMPLER_2D_RECT

isampler2DRect

GL_UNSIGNED_INT_SAMPLER_1D

usampler1D

GL_UNSIGNED_INT_SAMPLER_2D

usampler2D

GL_UNSIGNED_INT_SAMPLER_3D

usampler3D

GL_UNSIGNED_INT_SAMPLER_CUBE

usamplerCube

GL_UNSIGNED_INT_SAMPLER_1D_ARRAY

usampler2DArray

GL_UNSIGNED_INT_SAMPLER_2D_ARRAY

usampler2DArray

GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE

usampler2DMS

GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE_ARRAY

usampler2DMSArray

GL_UNSIGNED_INT_SAMPLER_BUFFER

usamplerBuffer

GL_UNSIGNED_INT_SAMPLER_2D_RECT

usampler2DRect

If pname
is GL_UNIFORM_SIZE
, then an array identifying the
size of the uniforms specified by the corresponding array of uniformIndices
is
returned. The sizes returned are in units of the type returned by a query of GL_UNIFORM_TYPE
.
For active uniforms that are arrays, the size is the number of active elements in the array;
for all other uniforms, the size is one.
If pname
is GL_UNIFORM_NAME_LENGTH
, then an array identifying the
length, including the terminating null character, of the uniform name strings specified by the corresponding
array of uniformIndices
is returned.
If pname
is GL_UNIFORM_BLOCK_INDEX
, then an array identifying the
the uniform block index of each of the uniforms specified by the corresponding array of uniformIndices
is returned. The uniform block index of a uniform associated with the default uniform block is 1.
If pname
is GL_UNIFORM_OFFSET
, then an array of uniform buffer
offsets is returned. For uniforms in a named uniform block, the returned value will be its offset, in basic
machine units, relative to the beginning of the uniform block in the buffer object data store. For uniforms
in the default uniform block, 1 will be returned.
If pname
is GL_UNIFORM_ARRAY_STRIDE
, then an array identifying the
stride between elements, in basic machine units, of each of the uniforms specified by the corresponding array of
uniformIndices
is returned. The stride of a uniform associated with the default uniform
block is 1. Note that this information only makes sense for uniforms that are arrays. For uniforms that are
not arrays, but are declared in a named uniform block, an array stride of zero is returned.
If pname
is GL_UNIFORM_MATRIX_STRIDE
, then an array identifying the stride
between columns of a columnmajor matrix or rows of a rowmajor matrix, in basic machine units, of each of the uniforms
specified by the corresponding array of uniformIndices
is returned. The matrix stride of a
uniform associated with the default uniform block is 1. Note that this information only makes sense for uniforms
that are matrices. For uniforms that are not matrices, but are declared in a named uniform block, a matrix stride of
zero is returned.
If pname
is GL_UNIFORM_IS_ROW_MAJOR
, then an array identifying whether each
of the uniforms specified by the corresponding array of uniformIndices
is a rowmajor matrix or not is returned. A
value of one indicates a rowmajor matrix, and a value of zero indicates a columnmajor matrix, a matrix in the default
uniform block, or a nonmatrix.
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_VALUE
is generated if
uniformCount
is greater than or equal to the
value of GL_ACTIVE_UNIFORMS
for
program
.
GL_INVALID_ENUM
is generated if pname
is not an accepted token.
glGet
with argument GL_MAX_VERTEX_UNIFORM_COMPONENTS
,
GL_MAX_GEOMETRY_UNIFORM_COMPONENTS
,
GL_MAX_FRAGMENT_UNIFORM_COMPONENTS
,
GL_MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS
,
GL_MAX_COMBINED_GEOMETRY_UNIFORM_COMPONENTS
,
GL_MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS
.
glGetProgram
with argument GL_ACTIVE_UNIFORMS
or
GL_ACTIVE_UNIFORM_MAX_LENGTH
.
glGetUniform, glGetActiveUniform, glGetUniformLocation, glLinkProgram, glUniform, glUseProgram
Copyright © 2011 Khronos Group This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.