GLGET(3G)

NAME
glGet - return the value or values of a selected parameter

C SPECIFICATION

void glGetBooleanv(GLenum pname, GLboolean * params);

C SPECIFICATION

void glGetDoublev(GLenum pname, GLdouble * params);

C SPECIFICATION

void glGetFloatv(GLenum pname, GLfloat * params);

C SPECIFICATION

void glGetIntegerv(GLenum pname, GLint * params);

C SPECIFICATION

void glGetInteger64v(GLenum pname, GLint64 * params);

PARAMETERS

pname
    Specifies the parameter value to be returned. The symbolic constants in the list below are accepted.

params
    Returns the value or values of the specified parameter.

C SPECIFICATION

void glGetBooleani_v(GLenum pname, GLuint index, GLboolean * data);

C SPECIFICATION

void glGetIntegeri_v(GLenum pname, GLuint index, GLint * data);

C SPECIFICATION

void glGetInteger64i_v(GLenum pname, GLuint index, GLint64 * data);

PARAMETERS

pname
    Specifies the parameter value to be returned. The symbolic constants in the list below are accepted.

index
    Specifies the index of the particular element being queried.

data
    Returns the value or values of the specified parameter.

DESCRIPTION

These four commands return values for simple state variables in GL. pname is a symbolic constant indicating the state variable to be returned, and params is a pointer to an array of the indicated type in which to place the returned data.

Type conversion is performed if params has a different type than the state variable value being requested. If glGetBooleanv is called, a floating-point (or integer) value is converted to GL_FALSE if and only if it is 0.0 (or 0). Otherwise, it is converted to GL_TRUE. If glGetIntegerv is called, boolean values are returned as GL_TRUE or GL_FALSE, and most floating-point values are rounded to the nearest integer value. Floating-point colors and normals, however, are returned with a linear mapping that maps 1.0 to the most positive representable integer value and -1.0 to the most negative representable integer value. If glGetFloatv or glGetDoublev is called, boolean values are returned as GL_TRUE or GL_FALSE, and integer values are converted to floating-point values.

The following symbolic constants are accepted by pname:

GL_ACTIVE_TEXTURE

    params returns a single value indicating the active multitexture unit. The initial value is GL_TEXTURE0. See glActiveTexture().

GL_ALIASED_LINE_WIDTH_RANGE

    params returns a pair of values indicating the range of widths supported for aliased lines. See glLineWidth().

GL_SMOOTH_LINE_WIDTH_RANGE

    params returns a pair of values indicating the range of widths supported for smooth (antialiased) lines. See glLineWidth().

GL_SMOOTH_LINE_WIDTH_GRANULARITY

    params returns a single value indicating the level of quantization applied to smooth line width parameters.

GL_ARRAY_BUFFER_BINDING

    params returns a single value, the name of the buffer object currently bound to the target GL_ARRAY_BUFFER. If no buffer object is bound to this target, 0 is returned. The initial value is 0. See glBindBuffer().

GL_BLEND

    params returns a single boolean value indicating whether blending is enabled. The initial value is GL_FALSE. See glBlendFunc().

GL_BLEND_COLOR

    params returns four values, the red, green, blue, and alpha values which are the components of the blend color. See glBlendColor().

GL_BLEND_DST_ALPHA

    params returns one value, the symbolic constant identifying the alpha destination blend function. The initial value is GL_ZERO. See glBlendFunc() and glBlendFuncSeparate().

GL_BLEND_DST_RGB

    params returns one value, the symbolic constant identifying the RGB destination blend function. The initial value is GL_ZERO. See glBlendFunc() and glBlendFuncSeparate().

GL_BLEND_EQUATION_RGB

    params returns one value, a symbolic constant indicating whether the RGB blend equation is GL_FUNC_ADD, GL_FUNC_SUBTRACT, GL_FUNC_REVERSE_SUBTRACT, GL_MIN or GL_MAX. See glBlendEquationSeparate().

GL_BLEND_EQUATION_ALPHA

    params returns one value, a symbolic constant indicating whether the Alpha blend equation is GL_FUNC_ADD, GL_FUNC_SUBTRACT, GL_FUNC_REVERSE_SUBTRACT, GL_MIN or GL_MAX. See glBlendEquationSeparate().

GL_BLEND_SRC_ALPHA

    params returns one value, the symbolic constant identifying the alpha source blend function. The initial value is GL_ONE. See glBlendFunc() and glBlendFuncSeparate().

GL_BLEND_SRC_RGB

    params returns one value, the symbolic constant identifying the RGB source blend function. The initial value is GL_ONE. See glBlendFunc() and glBlendFuncSeparate().

GL_COLOR_CLEAR_VALUE

    params returns four values: the red, green, blue, and alpha values used to clear the color buffers. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (0, 0, 0, 0). See glClearColor().

GL_COLOR_LOGIC_OP

    params returns a single boolean value indicating whether a fragment's RGBA color values are merged into the framebuffer using a logical operation. The initial value is GL_FALSE. See glLogicOp().

GL_COLOR_WRITEMASK

    params returns four boolean values: the red, green, blue, and alpha write enables for the color buffers. The initial value is (GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE). See glColorMask().

GL_COMPRESSED_TEXTURE_FORMATS

    params returns a list of symbolic constants of length GL_NUM_COMPRESSED_TEXTURE_FORMATS indicating which compressed texture formats are available. See glCompressedTexImage2D().

GL_CULL_FACE

    params returns a single boolean value indicating whether polygon culling is enabled. The initial value is GL_FALSE. See glCullFace().

GL_CURRENT_PROGRAM

    params returns one value, the name of the program object that is currently active, or 0 if no program object is active. See glUseProgram().

GL_DEPTH_CLEAR_VALUE

    params returns one value, the value that is used to clear the depth buffer. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is 1. See glClearDepth().

GL_DEPTH_FUNC

    params returns one value, the symbolic constant that indicates the depth comparison function. The initial value is GL_LESS. See glDepthFunc().

GL_DEPTH_RANGE

    params returns two values: the near and far mapping limits for the depth buffer. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (0, 1). See glDepthRange().

GL_DEPTH_TEST

    params returns a single boolean value indicating whether depth testing of fragments is enabled. The initial value is GL_FALSE. See glDepthFunc() and glDepthRange().

GL_DEPTH_WRITEMASK

    params returns a single boolean value indicating if the depth buffer is enabled for writing. The initial value is GL_TRUE. See glDepthMask().

GL_DITHER

    params returns a single boolean value indicating whether dithering of fragment colors and indices is enabled. The initial value is GL_TRUE.

GL_DOUBLEBUFFER

    params returns a single boolean value indicating whether double buffering is supported.

GL_DRAW_BUFFER

    params returns one value, a symbolic constant indicating which buffers are being drawn to. See glDrawBuffer(). The initial value is GL_BACK if there are back buffers, otherwise it is GL_FRONT.

GL_DRAW_BUFFERi

    params returns one value, a symbolic constant indicating which buffers are being drawn to by the corresponding output color. See glDrawBuffers(). The initial value of GL_DRAW_BUFFER0 is GL_BACK if there are back buffers, otherwise it is GL_FRONT. The initial values of draw buffers for all other output colors is GL_NONE.

GL_DRAW_FRAMEBFUFER_BINDING

    params returns one value, the name of the framebuffer object currently bound to the GL_DRAW_FRAMEBUFFER target. If the default framebuffer is bound, this value will be zero. The initial value is zero. See glBindFramebuffer().

GL_READ_FRAMEBFUFER_BINDING

    params returns one value, the name of the framebuffer object currently bound to the GL_READ_FRAMEBUFFER target. If the default framebuffer is bound, this value will be zero. The initial value is zero. See glBindFramebuffer().

GL_ELEMENT_ARRAY_BUFFER_BINDING

    params returns a single value, the name of the buffer object currently bound to the target GL_ELEMENT_ARRAY_BUFFER. If no buffer object is bound to this target, 0 is returned. The initial value is 0. See glBindBuffer().

GL_RENDERBUFFER_BINDING

    params returns a single value, the name of the renderbuffer object currently bound to the target GL_RENDERBUFFER. If no renderbuffer object is bound to this target, 0 is returned. The initial value is 0. See glBindRenderbuffer().

GL_FRAGMENT_SHADER_DERIVATIVE_HINT

    params returns one value, a symbolic constant indicating the mode of the derivative accuracy hint for fragment shaders. The initial value is GL_DONT_CARE. See glHint().

GL_LINE_SMOOTH

    params returns a single boolean value indicating whether antialiasing of lines is enabled. The initial value is GL_FALSE. See glLineWidth().

GL_LINE_SMOOTH_HINT

    params returns one value, a symbolic constant indicating the mode of the line antialiasing hint. The initial value is GL_DONT_CARE. See glHint().

GL_LINE_WIDTH

    params returns one value, the line width as specified with glLineWidth(). The initial value is 1.

GL_LINE_WIDTH_GRANULARITY

    params returns one value, the width difference between adjacent supported widths for antialiased lines. See glLineWidth().

GL_LINE_WIDTH_RANGE

    params returns two values: the smallest and largest supported widths for antialiased lines. See glLineWidth().

GL_LOGIC_OP_MODE

    params returns one value, a symbolic constant indicating the selected logic operation mode. The initial value is GL_COPY. See glLogicOp().

GL_MAX_3D_TEXTURE_SIZE

    params returns one value, a rough estimate of the largest 3D texture that the GL can handle. The value must be at least 64. Use GL_PROXY_TEXTURE_3D to determine if a texture is too large. See glTexImage3D().

GL_MAX_CLIP_DISTANCES

    params returns one value, the maximum number of application-defined clipping distances. The value must be at least 8.

GL_MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS

    params returns one value, the number of words for fragment shader uniform variables in all uniform blocks (including default). The value must be at least 1. See glUniform().

GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS

    params returns one value, the maximum supported texture image units that can be used to access texture maps from the vertex shader and the fragment processor combined. If both the vertex shader and the fragment processing stage access the same texture image unit, then that counts as using two texture image units against this limit. The value must be at least 48. See glActiveTexture().

GL_MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS

    params returns one value, the number of words for vertex shader uniform variables in all uniform blocks (including default). The value must be at least 1. See glUniform().

GL_MAX_COMBINED_GEOMETRY_UNIFORM_COMPONENTS

    params returns one value, the number of words for geometry shader uniform variables in all uniform blocks (including default). The value must be at least 1. See glUniform().

GL_MAX_VARYING_COMPONENTS

    params returns one value, the number components for varying variables, which must be at least 60.

GL_MAX_COMBINED_UNIFORM_BLOCKS

    params returns one value, the maximum number of uniform blocks per program. The value must be at least 36. See glUniformBlockBinding().

GL_MAX_CUBE_MAP_TEXTURE_SIZE

    params returns one value. The value gives a rough estimate of the largest cube-map texture that the GL can handle. The value must be at least 1024. Use GL_PROXY_TEXTURE_CUBE_MAP to determine if a texture is too large. See glTexImage2D().

GL_MAX_DRAW_BUFFERS

    params returns one value, the maximum number of simultaneous outputs that may be written in a fragment shader. The value must be at least 8. See glDrawBuffers().

GL_MAX_DUALSOURCE_DRAW_BUFFERS

    params returns one value, the maximum number of active draw buffers when using dual-source blending. The value must be at least 1. See glBlendFunc() and glBlendFuncSeparate().

GL_MAX_ELEMENTS_INDICES

    params returns one value, the recommended maximum number of vertex array indices. See glDrawRangeElements().

GL_MAX_ELEMENTS_VERTICES

    params returns one value, the recommended maximum number of vertex array vertices. See glDrawRangeElements().

GL_MAX_FRAGMENT_UNIFORM_COMPONENTS

    params returns one value, the maximum number of individual floating-point, integer, or boolean values that can be held in uniform variable storage for a fragment shader. The value must be at least 1024. See glUniform().

GL_MAX_FRAGMENT_UNIFORM_BLOCKS

    params returns one value, the maximum number of uniform blocks per fragment shader. The value must be at least 12. See glUniformBlockBinding().

GL_MAX_FRAGMENT_INPUT_COMPONENTS

    params returns one value, the maximum number of components of the inputs read by the fragment shader, which must be at least 128.

GL_MIN_PROGRAM_TEXEL_OFFSET

    params returns one value, the minimum texel offset allowed in a texture lookup, which must be at most -8.

GL_MAX_PROGRAM_TEXEL_OFFSET

    params returns one value, the maximum texel offset allowed in a texture lookup, which must be at least 7.

GL_MAX_RECTANGLE_TEXTURE_SIZE

    params returns one value. The value gives a rough estimate of the largest rectangular texture that the GL can handle. The value must be at least 1024. Use GL_PROXY_RECTANGLE_TEXTURE to determine if a texture is too large. See glTexImage2D().

GL_MAX_TEXTURE_IMAGE_UNITS

    params returns one value, the maximum supported texture image units that can be used to access texture maps from the fragment shader. The value must be at least 16. See glActiveTexture().

GL_MAX_TEXTURE_LOD_BIAS

    params returns one value, the maximum, absolute value of the texture level-of-detail bias. The value must be at least 2.0.

GL_MAX_TEXTURE_SIZE

    params returns one value. The value gives a rough estimate of the largest texture that the GL can handle. The value must be at least 1024. Use a proxy texture target such as GL_PROXY_TEXTURE_1D or GL_PROXY_TEXTURE_2D to determine if a texture is too large. See glTexImage1D() and glTexImage2D().

GL_MAX_RENDERBUFFER_SIZE

    params returns one value. The value indicates the maximum supported size for renderbuffers. See glFramebufferRenderbuffer().

GL_MAX_ARRAY_TEXTURE_LAYERS

    params returns one value. The value indicates the maximum number of layers allowed in an array texture, and must be at least 256. See glTexImage2D().

GL_MAX_TEXTURE_BUFFER_SIZE

    params returns one value. The value gives the maximum number of texels allowed in the texel array of a texture buffer object. Value must be at least 65536.

GL_MAX_UNIFORM_BLOCK_SIZE

    params returns one value, the maximum size in basic machine units of a uniform block. The value must be at least 16384. See glUniformBlockBinding().

GL_MAX_VARYING_FLOATS

    params returns one value, the maximum number of interpolators available for processing varying variables used by vertex and fragment shaders. This value represents the number of individual floating-point values that can be interpolated; varying variables declared as vectors, matrices, and arrays will all consume multiple interpolators. The value must be at least 32.

GL_MAX_VERTEX_ATTRIBS

    params returns one value, the maximum number of 4-component generic vertex attributes accessible to a vertex shader. The value must be at least 16. See glVertexAttrib().

GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS

    params returns one value, the maximum supported texture image units that can be used to access texture maps from the vertex shader. The value may be at least 16. See glActiveTexture().

GL_MAX_GEOMETRY_TEXTURE_IMAGE_UNITS

    params returns one value, the maximum supported texture image units that can be used to access texture maps from the geometry shader. The value must be at least 16. See glActiveTexture().

GL_MAX_VERTEX_UNIFORM_COMPONENTS

    params returns one value, the maximum number of individual floating-point, integer, or boolean values that can be held in uniform variable storage for a vertex shader. The value must be at least 1024. See glUniform().

GL_MAX_VERTEX_OUTPUT_COMPONENTS

    params returns one value, the maximum number of components of output written by a vertex shader, which must be at least 64.

GL_MAX_GEOMETRY_UNIFORM_COMPONENTS

    params returns one value, the maximum number of individual floating-point, integer, or boolean values that can be held in uniform variable storage for a geometry shader. The value must be at least 1024. See glUniform().

GL_MAX_SAMPLE_MASK_WORDS

    params returns one value, the maximum number of sample mask words.

GL_MAX_COLOR_TEXTURE_SAMPLES

    params returns one value, the maximum number of samples in a color multisample texture.

GL_MAX_DEPTH_TEXTURE_SAMPLES

    params returns one value, the maximum number of samples in a multisample depth or depth-stencil texture.

GL_MAX_DEPTH_TEXTURE_SAMPLES

    params returns one value, the maximum number of samples in a multisample depth or depth-stencil texture.

GL_MAX_INTEGER_SAMPLES

    params returns one value, the maximum number of samples supported in integer format multisample buffers.

GL_MAX_SERVER_WAIT_TIMEOUT

    params returns one value, the maximum glWaitSync() timeout interval.

GL_MAX_UNIFORM_BUFFER_BINDINGS

    params returns one value, the maximum number of uniform buffer binding points on the context, which must be at least 36.

GL_MAX_UNIFORM_BLOCK_SIZE

    params returns one value, the maximum size in basic machine units of a uniform block, which must be at least 16384.

GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT

    params returns one value, the minimum required alignment for uniform buffer sizes and offsets.

GL_MAX_VERTEX_UNIFORM_BLOCKS

    params returns one value, the maximum number of uniform blocks per vertex shader. The value must be at least 12. See glUniformBlockBinding().

GL_MAX_GEOMETRY_UNIFORM_BLOCKS

    params returns one value, the maximum number of uniform blocks per geometry shader. The value must be at least 12. See glUniformBlockBinding().

GL_MAX_GEOMETRY_INPUT_COMPONENTS

    params returns one value, the maximum number of components of inputs read by a geometry shader, which must be at least 64.

GL_MAX_GEOMETRY_OUTPUT_COMPONENTS

    params returns one value, the maximum number of components of outputs written by a geometry shader, which must be at least 128.

GL_MAX_VIEWPORT_DIMS

    params returns two values: the maximum supported width and height of the viewport. These must be at least as large as the visible dimensions of the display being rendered to. See glViewport().

GL_NUM_COMPRESSED_TEXTURE_FORMATS

    params returns a single integer value indicating the number of available compressed texture formats. The minimum value is 4. See glCompressedTexImage2D().

GL_PACK_ALIGNMENT

    params returns one value, the byte alignment used for writing pixel data to memory. The initial value is 4. See glPixelStore().

GL_PACK_IMAGE_HEIGHT

    params returns one value, the image height used for writing pixel data to memory. The initial value is 0. See glPixelStore().

GL_PACK_LSB_FIRST

    params returns a single boolean value indicating whether single-bit pixels being written to memory are written first to the least significant bit of each unsigned byte. The initial value is GL_FALSE. See glPixelStore().

GL_PACK_ROW_LENGTH

    params returns one value, the row length used for writing pixel data to memory. The initial value is 0. See glPixelStore().

GL_PACK_SKIP_IMAGES

    params returns one value, the number of pixel images skipped before the first pixel is written into memory. The initial value is 0. See glPixelStore().

GL_PACK_SKIP_PIXELS

    params returns one value, the number of pixel locations skipped before the first pixel is written into memory. The initial value is 0. See glPixelStore().

GL_PACK_SKIP_ROWS

    params returns one value, the number of rows of pixel locations skipped before the first pixel is written into memory. The initial value is 0. See glPixelStore().

GL_PACK_SWAP_BYTES

    params returns a single boolean value indicating whether the bytes of two-byte and four-byte pixel indices and components are swapped before being written to memory. The initial value is GL_FALSE. See glPixelStore().

GL_PIXEL_PACK_BUFFER_BINDING

    params returns a single value, the name of the buffer object currently bound to the target GL_PIXEL_PACK_BUFFER. If no buffer object is bound to this target, 0 is returned. The initial value is 0. See glBindBuffer().

GL_PIXEL_UNPACK_BUFFER_BINDING

    params returns a single value, the name of the buffer object currently bound to the target GL_PIXEL_UNPACK_BUFFER. If no buffer object is bound to this target, 0 is returned. The initial value is 0. See glBindBuffer().

GL_POINT_FADE_THRESHOLD_SIZE

    params returns one value, the point size threshold for determining the point size. See glPointParameter().

GL_PRIMITIVE_RESTART_INDEX

    params returns one value, the current primitive restart index. The initial value is 0. See glPrimitiveRestartIndex().

GL_PROVOKING_VERTEX

    params returns one value, the currently selected provoking vertex convention. The initial value is GL_LAST_VERTEX_CONVENTION. See glProvokingVertex().

GL_POINT_SIZE

    params returns one value, the point size as specified by glPointSize(). The initial value is 1.

GL_POINT_SIZE_GRANULARITY

    params returns one value, the size difference between adjacent supported sizes for antialiased points. See glPointSize().

GL_POINT_SIZE_RANGE

    params returns two values: the smallest and largest supported sizes for antialiased points. The smallest size must be at most 1, and the largest size must be at least 1. See glPointSize().

GL_POLYGON_OFFSET_FACTOR

    params returns one value, the scaling factor used to determine the variable offset that is added to the depth value of each fragment generated when a polygon is rasterized. The initial value is 0. See glPolygonOffset().

GL_POLYGON_OFFSET_UNITS

    params returns one value. This value is multiplied by an implementation-specific value and then added to the depth value of each fragment generated when a polygon is rasterized. The initial value is 0. See glPolygonOffset().

GL_POLYGON_OFFSET_FILL

    params returns a single boolean value indicating whether polygon offset is enabled for polygons in fill mode. The initial value is GL_FALSE. See glPolygonOffset().

GL_POLYGON_OFFSET_LINE

    params returns a single boolean value indicating whether polygon offset is enabled for polygons in line mode. The initial value is GL_FALSE. See glPolygonOffset().

GL_POLYGON_OFFSET_POINT

    params returns a single boolean value indicating whether polygon offset is enabled for polygons in point mode. The initial value is GL_FALSE. See glPolygonOffset().

GL_POLYGON_SMOOTH

    params returns a single boolean value indicating whether antialiasing of polygons is enabled. The initial value is GL_FALSE. See glPolygonMode().

GL_POLYGON_SMOOTH_HINT

    params returns one value, a symbolic constant indicating the mode of the polygon antialiasing hint. The initial value is GL_DONT_CARE. See glHint().

GL_READ_BUFFER

    params returns one value, a symbolic constant indicating which color buffer is selected for reading. The initial value is GL_BACK if there is a back buffer, otherwise it is GL_FRONT. See glReadPixels().

GL_SAMPLE_BUFFERS

    params returns a single integer value indicating the number of sample buffers associated with the framebuffer. See glSampleCoverage().

GL_SAMPLE_COVERAGE_VALUE

    params returns a single positive floating-point value indicating the current sample coverage value. See glSampleCoverage().

GL_SAMPLE_COVERAGE_INVERT

    params returns a single boolean value indicating if the temporary coverage value should be inverted. See glSampleCoverage().

GL_SAMPLER_BINDING

    params returns a single value, the name of the sampler object currently bound to the active texture unit. The initial value is 0. See glBindSampler().

GL_SAMPLES

    params returns a single integer value indicating the coverage mask size. See glSampleCoverage().

GL_SCISSOR_BOX

    params returns four values: the x and y window coordinates of the scissor box, followed by its width and height. Initially the x and y window coordinates are both 0 and the width and height are set to the size of the window. See glScissor().

GL_SCISSOR_TEST

    params returns a single boolean value indicating whether scissoring is enabled. The initial value is GL_FALSE. See glScissor().

GL_STENCIL_BACK_FAIL

    params returns one value, a symbolic constant indicating what action is taken for back-facing polygons when the stencil test fails. The initial value is GL_KEEP. See glStencilOpSeparate().

GL_STENCIL_BACK_FUNC

    params returns one value, a symbolic constant indicating what function is used for back-facing polygons to compare the stencil reference value with the stencil buffer value. The initial value is GL_ALWAYS. See glStencilFuncSeparate().

GL_STENCIL_BACK_PASS_DEPTH_FAIL

    params returns one value, a symbolic constant indicating what action is taken for back-facing polygons when the stencil test passes, but the depth test fails. The initial value is GL_KEEP. See glStencilOpSeparate().

GL_STENCIL_BACK_PASS_DEPTH_PASS

    params returns one value, a symbolic constant indicating what action is taken for back-facing polygons when the stencil test passes and the depth test passes. The initial value is GL_KEEP. See glStencilOpSeparate().

GL_STENCIL_BACK_REF

    params returns one value, the reference value that is compared with the contents of the stencil buffer for back-facing polygons. The initial value is 0. See glStencilFuncSeparate().

GL_STENCIL_BACK_VALUE_MASK

    params returns one value, the mask that is used for back-facing polygons to mask both the stencil reference value and the stencil buffer value before they are compared. The initial value is all 1's. See glStencilFuncSeparate().

GL_STENCIL_BACK_WRITEMASK

    params returns one value, the mask that controls writing of the stencil bitplanes for back-facing polygons. The initial value is all 1's. See glStencilMaskSeparate().

GL_STENCIL_CLEAR_VALUE

    params returns one value, the index to which the stencil bitplanes are cleared. The initial value is 0. See glClearStencil().

GL_STENCIL_FAIL

    params returns one value, a symbolic constant indicating what action is taken when the stencil test fails. The initial value is GL_KEEP. See glStencilOp(). This stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See glStencilOpSeparate().

GL_STENCIL_FUNC

    params returns one value, a symbolic constant indicating what function is used to compare the stencil reference value with the stencil buffer value. The initial value is GL_ALWAYS. See glStencilFunc(). This stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See glStencilFuncSeparate().

GL_STENCIL_PASS_DEPTH_FAIL

    params returns one value, a symbolic constant indicating what action is taken when the stencil test passes, but the depth test fails. The initial value is GL_KEEP. See glStencilOp(). This stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See glStencilOpSeparate().

GL_STENCIL_PASS_DEPTH_PASS

    params returns one value, a symbolic constant indicating what action is taken when the stencil test passes and the depth test passes. The initial value is GL_KEEP. See glStencilOp(). This stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See glStencilOpSeparate().

GL_STENCIL_REF

    params returns one value, the reference value that is compared with the contents of the stencil buffer. The initial value is 0. See glStencilFunc(). This stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See glStencilFuncSeparate().

GL_STENCIL_TEST

    params returns a single boolean value indicating whether stencil testing of fragments is enabled. The initial value is GL_FALSE. See glStencilFunc() and glStencilOp().

GL_STENCIL_VALUE_MASK

    params returns one value, the mask that is used to mask both the stencil reference value and the stencil buffer value before they are compared. The initial value is all 1's. See glStencilFunc(). This stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See glStencilFuncSeparate().

GL_STENCIL_WRITEMASK

    params returns one value, the mask that controls writing of the stencil bitplanes. The initial value is all 1's. See glStencilMask(). This stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See glStencilMaskSeparate().

GL_STEREO

    params returns a single boolean value indicating whether stereo buffers (left and right) are supported.

GL_SUBPIXEL_BITS

    params returns one value, an estimate of the number of bits of subpixel resolution that are used to position rasterized geometry in window coordinates. The value must be at least 4.

GL_TEXTURE_BINDING_1D

    params returns a single value, the name of the texture currently bound to the target GL_TEXTURE_1D. The initial value is 0. See glBindTexture().

GL_TEXTURE_BINDING_1D_ARRAY

    params returns a single value, the name of the texture currently bound to the target GL_TEXTURE_1D_ARRAY. The initial value is 0. See glBindTexture().

GL_TEXTURE_BINDING_2D

    params returns a single value, the name of the texture currently bound to the target GL_TEXTURE_2D. The initial value is 0. See glBindTexture().

GL_TEXTURE_BINDING_2D_ARRAY

    params returns a single value, the name of the texture currently bound to the target GL_TEXTURE_2D_ARRAY. The initial value is 0. See glBindTexture().

GL_TEXTURE_BINDING_2D_MULTISAMPLE

    params returns a single value, the name of the texture currently bound to the target GL_TEXTURE_2D_MULTISAMPLE. The initial value is 0. See glBindTexture().

GL_TEXTURE_BINDING_2D_MULTISAMPLE_ARRAY

    params returns a single value, the name of the texture currently bound to the target GL_TEXTURE_2D_MULTISAMPLE_ARRAY. The initial value is 0. See glBindTexture().

GL_TEXTURE_BINDING_3D

    params returns a single value, the name of the texture currently bound to the target GL_TEXTURE_3D. The initial value is 0. See glBindTexture().

GL_TEXTURE_BINDING_BUFFER

    params returns a single value, the name of the texture currently bound to the target GL_TEXTURE_BUFFER. The initial value is 0. See glBindTexture().

GL_TEXTURE_BINDING_CUBE_MAP

    params returns a single value, the name of the texture currently bound to the target GL_TEXTURE_CUBE_MAP. The initial value is 0. See glBindTexture().

GL_TEXTURE_BINDING_RECTANGLE

    params returns a single value, the name of the texture currently bound to the target GL_TEXTURE_RECTANGLE. The initial value is 0. See glBindTexture().

GL_TEXTURE_COMPRESSION_HINT

    params returns a single value indicating the mode of the texture compression hint. The initial value is GL_DONT_CARE.

GL_TEXTURE_BUFFER_BINDING

    params returns a single value, the name of the texture buffer object currently bound. The initial value is 0. See glBindBuffer().

GL_TIMESTAMP

    params returns a single value, the 64-bit value of the current GL time. See glQueryCounter().

GL_TRANSFORM_FEEDBACK_BUFFER_BINDING

    When used with non-indexed variants of glGet (such as glGetIntegerv), params returns a single value, the name of the buffer object currently bound to the target GL_TRANSFORM_FEEDBACK_BUFFER. If no buffer object is bound to this target, 0 is returned. When used with indexed variants of glGet (such as glGetIntegeri_v), params returns a single value, the name of the buffer object bound to the indexed transform feedback attribute stream. The initial value is 0 for all targets. See glBindBuffer(), glBindBufferBase(), and glBindBufferRange().

GL_TRANSFORM_FEEDBACK_BUFFER_START

    When used with indexed variants of glGet (such as glGetInteger64i_v), params returns a single value, the start offset of the binding range for each transform feedback attribute stream. The initial value is 0 for all streams. See glBindBufferRange().

GL_TRANSFORM_FEEDBACK_BUFFER_SIZE

    When used with indexed variants of glGet (such as glGetInteger64i_v), params returns a single value, the size of the binding range for each transform feedback attribute stream. The initial value is 0 for all streams. See glBindBufferRange().

GL_UNIFORM_BUFFER_BINDING

    When used with non-indexed variants of glGet (such as glGetIntegerv), params returns a single value, the name of the buffer object currently bound to the target GL_UNIFORM_BUFFER. If no buffer object is bound to this target, 0 is returned. When used with indexed variants of glGet (such as glGetIntegeri_v), params returns a single value, the name of the buffer object bound to the indexed uniform buffer binding point. The initial value is 0 for all targets. See glBindBuffer(), glBindBufferBase(), and glBindBufferRange().

GL_UNIFORM_BUFFER_START

    When used with indexed variants of glGet (such as glGetInteger64i_v), params returns a single value, the start offset of the binding range for each indexed uniform buffer binding. The initial value is 0 for all bindings. See glBindBufferRange().

GL_UNIFORM_BUFFER_SIZE

    When used with indexed variants of glGet (such as glGetInteger64i_v), params returns a single value, the size of the binding range for each indexed uniform buffer binding. The initial value is 0 for all bindings. See glBindBufferRange().

GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT

    params returns a single value, the minimum required alignment for uniform buffer sizes and offset. The initial value is 1. See glUniformBlockBinding().

GL_UNPACK_ALIGNMENT

    params returns one value, the byte alignment used for reading pixel data from memory. The initial value is 4. See glPixelStore().

GL_UNPACK_IMAGE_HEIGHT

    params returns one value, the image height used for reading pixel data from memory. The initial is 0. See glPixelStore().

GL_UNPACK_LSB_FIRST

    params returns a single boolean value indicating whether single-bit pixels being read from memory are read first from the least significant bit of each unsigned byte. The initial value is GL_FALSE. See glPixelStore().

GL_UNPACK_ROW_LENGTH

    params returns one value, the row length used for reading pixel data from memory. The initial value is 0. See glPixelStore().

GL_UNPACK_SKIP_IMAGES

    params returns one value, the number of pixel images skipped before the first pixel is read from memory. The initial value is 0. See glPixelStore().

GL_UNPACK_SKIP_PIXELS

    params returns one value, the number of pixel locations skipped before the first pixel is read from memory. The initial value is 0. See glPixelStore().

GL_UNPACK_SKIP_ROWS

    params returns one value, the number of rows of pixel locations skipped before the first pixel is read from memory. The initial value is 0. See glPixelStore().

GL_UNPACK_SWAP_BYTES

    params returns a single boolean value indicating whether the bytes of two-byte and four-byte pixel indices and components are swapped after being read from memory. The initial value is GL_FALSE. See glPixelStore().

GL_NUM_EXTENSIONS

    params returns one value, the number of extensions supported by the GL implementation for the current context. See glGetString().

GL_MAJOR_VERSION

    params returns one value, the major version number of the OpenGL API supported by the current context.

GL_MINOR_VERSION

    params returns one value, the minor version number of the OpenGL API supported by the current context.

GL_CONTEXT_FLAGS

    params returns one value, the flags with which the context was created (such as debugging functionality).

GL_VERTEX_PROGRAM_POINT_SIZE

    params returns a single boolean value indicating whether vertex program point size mode is enabled. If enabled, and a vertex shader is active, then the point size is taken from the shader built-in gl_PointSize. If disabled, and a vertex shader is active, then the point size is taken from the point state as specified by glPointSize(). The initial value is GL_FALSE.

GL_VIEWPORT

    params returns four values: the x and y window coordinates of the viewport, followed by its width and height. Initially the x and y window coordinates are both set to 0, and the width and height are set to the width and height of the window into which the GL will do its rendering. See glViewport().

Many of the boolean parameters can also be queried more easily using glIsEnabled().

NOTES

The following parameters return the associated value for the active texture unit: GL_TEXTURE_1D, GL_TEXTURE_BINDING_1D, GL_TEXTURE_2D, GL_TEXTURE_BINDING_2D, GL_TEXTURE_3D and GL_TEXTURE_BINDING_3D.

GL_MAX_RECTANGLE_TEXTURE_SIZE, GL_MAX_TEXTURE_BUFFER_SIZE, GL_UNIFORM_BUFFER_BINDING, GL_TEXTURE_BUFFER_BINDING, GL_MAX_VERTEX_UNIFORM_BLOCKS, GL_MAX_FRAGMENT_UNIFORM_BLOCKS, GL_MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS, GL_MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS GL_MAX_COMBINED_UNIFORM_BLOCKS, GL_MAX_UNIFORM_BLOCK_SIZE, and GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT are available only if the GL version is 3.1 or greater.

GL_MAX_COMBINED_GEOMETRY_UNIFORM_COMPONENTS, GL_MAX_GEOMETRY_UNIFORM_BLOCKS, GL_MAX_GEOMETRY_INPUT_COMPONENTS, GL_MAX_GEOMETRY_OUTPUT_COMPONENTS, GL_MAX_GEOMETRY_OUTPUT_VERTICES, GL_MAX_GEOMETRY_TOTAL_OUTPUT_COMPONENTS and GL_MAX_GEOMETRY_TEXTURE_IMAGE_UNITS are available only if the GL version is 3.2 or greater.

glGetInteger64v and glGetInteger64i_v are available only if the GL version is 3.2 or greater.

GL_MAX_DUALSOURCE_DRAW_BUFFERS, GL_SAMPLER_BINDING, and GL_TIMESTAMP are available only if the GL version is 3.3 or greater.

ERRORS

GL_INVALID_ENUM is generated if pname is not an accepted value.

GL_INVALID_VALUE is generated on any of glGetBooleani_v, glGetIntegeri_v, or glGetInteger64i_v if index is outside of the valid range for the indexed state target.

SEE ALSO

glGetActiveUniform(), glGetAttachedShaders(), glGetAttribLocation(), glGetBufferParameter(), glGetBufferPointerv(), glGetBufferSubData(), glGetCompressedTexImage(), glGetError(), glGetProgram(), glGetProgramInfoLog(), glGetQueryiv(), glGetQueryObject(), glGetShader(), glGetShaderInfoLog(), glGetShaderSource(), glGetString(), glGetTexImage(), glGetTexLevelParameter(), glGetTexParameter(), glGetUniform(), glGetUniformLocation(), glGetVertexAttrib(), glGetVertexAttribPointerv(), glIsEnabled()

COPYRIGHT

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.