glGetActiveUniformsiv 3G 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 pname. pname Specifies the property of the 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_DOUBLE double GL_DOUBLE_VEC2 dvec2 GL_DOUBLE_VEC3 dvec3 GL_DOUBLE_VEC4 dvec4 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_DOUBLE_MAT2 dmat2 GL_DOUBLE_MAT3 dmat3 GL_DOUBLE_MAT4 dmat4 GL_DOUBLE_MAT2x3 dmat2x3 GL_DOUBLE_MAT2x4 dmat2x4 GL_DOUBLE_MAT3x2 dmat3x2 GL_DOUBLE_MAT3x4 dmat3x4 GL_DOUBLE_MAT4x2 dmat4x2 GL_DOUBLE_MAT4x3 dmat4x3 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 atomic counter uniforms, the returned value will be its offset relative to the beginning of its active atomic counter buffer. For all other uniforms, -1 will be returned. If pname is GL_UNIFORM_ARRAY_STRIDE, then an array identifying the stride between elements of each of the uniforms specified by the corresponding array of uniformIndices is returned. For uniforms in named uniform blocks and for uniforms declared as atomic counters, the stride is the difference, in basic machine units, of consecutive elements in an array, or zero for uniforms not declared as an array. For all other uniforms, a stride of -1 will be returned. If pname is GL_UNIFORM_MATRIX_STRIDE, then an array identifying the stride between columns of a column-major matrix or rows of a row-major 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 row-major matrix or not is returned. A value of one indicates a row-major matrix, and a value of zero indicates a column-major matrix, a matrix in the default uniform block, or a non-matrix. If pname is GL_UNIFORM_ATOMIC_COUNTER_BUFFER_INDEX, then an array identifying the active atomic counter buffer index of each of the uniforms specified by the corresponding array of uniformIndices is returned. For uniforms other than atomic counters, the returned buffer index is -1. The returned indices may be passed to glGetActiveAtomicCounterBufferiv to query the properties of the associated buffer, and not necessarily the binding point specified in the uniform declaration. The double types, GL_DOUBLE, GL_DOUBLE_VEC2, GL_DOUBLE_VEC3, GL_DOUBLE_VEC4, GL_DOUBLE_MAT2, GL_DOUBLE_MAT3, GL_DOUBLE_MAT4, GL_DOUBLE_MAT2x3, GL_DOUBLE_MAT2x4, GL_DOUBLE_MAT3x2, GL_DOUBLE_MAT3x4, GL_DOUBLE_MAT4x2, and GL_DOUBLE_MAT4x3 are only available if the GL version is 4.1 or higher. GL_UNIFORM_ATOMIC_COUNTER_BUFFER_INDEX is only accepted by pname if the GL version is 4.2 or higher. 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_TESS_CONTROL_UNIFORM_COMPONENTS, GL_MAX_TESS_EVALUATION_UNIFORM_COMPONENTS, GL_MAX_GEOMETRY_UNIFORM_COMPONENTS, GL_MAX_FRAGMENT_UNIFORM_COMPONENTS, or GL_MAX_COMBINED_UNIFORM_COMPONENTS. glGetProgram with argument GL_ACTIVE_UNIFORMS or GL_ACTIVE_UNIFORM_MAX_LENGTH. glIsProgram 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/.