glGet

Definition: include pGUI.e
include opengl.e

glGetBooleanv(integer pname, atom pMem)
-- or --
glGetDoublev(integer pname, atom pMem)
-- or --
glGetFloatv(integer pname, atom pMem)
-- or --
glGetIntegerv(integer pname, atom pMem)
Description: The above four routines obtain the value or values of a selected parameter.

They do not return a value. The programmer is expected to allocate the required memory, select/invoke the appropriate routine, perform the required peek operation(s) or pass the memory area directly to some other opengl function, and finally free the memory.

pname: a symbolic constant from the table below.
pMem: an area of memory which will be populated by the call.

pname Type N Description
GL_ACCUM_ALPHA_BITS integer 1 the number of alpha bitplanes in the accumulation buffer.
GL_ACCUM_BLUE_BITS integer 1 the number of blue bitplanes in the accumulation buffer.
GL_ACCUM_CLEAR_VALUE atom1 4 the red, green, blue, and alpha values used to clear the accumulation buffer. See glClearAccum.
GL_ACCUM_GREEN_BITS integer 1 the number of green bitplanes in the accumulation buffer.
GL_ACCUM_RED_BITS integer 1 the number of red bitplanes in the accumulation buffer.
GL_ALPHA_BIAS atom 1 the alpha bias factor used during pixel transfers. See glPixelTransfer.
GL_ALPHA_BITS integer 1 the number of alpha bitplanes in each color buffer.
GL_ALPHA_SCALE atom 1 the alpha scale factor used during pixel transfers. See glPixelTransfer.
GL_ALPHA_TEST boolean 1 whether alpha testing of fragments is enabled. See glAlphaFunc.
GL_ALPHA_TEST_FUNC ptr? 1 the symbolic name of the alpha test function. See glAlphaFunc.
GL_ALPHA_TEST_REF atom1 1 the reference value for the alpha test. See glAlphaFunc.
GL_ATTRIB_STACK_DEPTH integer 1 the depth of the attribute stack. If the stack is empty, zero is returned. See glPushAttrib.
GL_AUTO_NORMAL boolean 1 whether 2-D map evaluation automatically generates surface normals. See glMap2.
GL_AUX_BUFFERS integer 1 the number of auxiliary color buffers.
GL_BLEND boolean 1 whether blending is enabled. See glBlendFunc.
GL_BLEND_DST integer 1 the symbolic constant identifying the destination blend function. See glBlendFunc.
GL_BLEND_SRC integer 1 the symbolic constant identifying the source blend function. See glBlendFunc.
GL_BLUE_BIAS atom 1 the blue bias factor used during pixel transfers. See glPixelTransfer.
GL_BLUE_BITS integer 1 the number of blue bitplanes in each color buffer.
GL_BLUE_SCALE atom 1 the blue scale factor used during pixel transfers. See glPixelTransfer.
GL_CLIENT_ATTRIB_STACK_DEPTH integer 1 the depth of the attribute stack. The initial value is zero. See glPushClientAttrib.
GL_CLIP_PLANEi boolean 1 whether the specified clipping plane is enabled. See glClipPlane.
GL_COLOR_ARRAY boolean 1 whether the specified color array is defined. See glColorPointer.
GL_COLOR_ARRAY_SIZE integer 1 the number of components per color in the color array. See glColorPointer.
GL_COLOR_ARRAY_STRIDE integer 1 the byte offset between consecutive colors in the color array. See glColorPointer.
GL_COLOR_ARRAY_TYPE integer 1 the data type of each component in the color array. See glColorPointer.
GL_COLOR_CLEAR_VALUE atom1 4 the red, green, blue, and alpha values used to clear the color buffers. See glClearColor.
GL_COLOR_LOGIC_OP boolean 1 whether a fragment’s RGBA color values are merged into the framebuffer using a logical operation. See glLogicOp.
GL_COLOR_MATERIAL boolean 1 whether one or more material parameters are tracking the current color. See glColorMaterial.
GL_COLOR_MATERIAL_FACE integer 1 a symbolic constant indicating which materials have a parameter that is tracking the current color. See glColorMaterial.
GL_COLOR_MATERIAL_PARAMETER integer 1 a symbolic constant indicating which material parameters are tracking the current color. See glColorMaterial.
GL_COLOR_WRITEMASK boolean 4 the red, green, blue, and alpha write enables for the color buffers. See glColorMask.
GL_CULL_FACE boolean 1 whether polygon culling is enabled. See glCullFace.
GL_CULL_FACE_MODE integer 1 a symbolic constant indicating which polygon faces are to be culled. See glCullFace.
GL_CURRENT_COLOR atom1 4 the red, green, blue, and alpha values of the current color. See glColor.
GL_CURRENT_INDEX atom? 1 the current color index. See glIndex.
GL_CURRENT_NORMAL atom1 3 the x, y, and z values of the current normal. See glNormal.
GL_CURRENT_RASTER_COLOR atom1 4 the red, green, blue, and alpha values of the current raster position. See glRasterPos.
GL_CURRENT_RASTER_DISTANCE atom 1 the distance from the eye to the current raster position. See glRasterPos.
GL_CURRENT_RASTER_INDEX atom? 1 the color index of the current raster position. See glRasterPos.
GL_CURRENT_RASTER_POSITION atom 4 the x, y, z, and w components of the current raster position. The x, y, and z components are in window coordinates, and w is in clip coordinates. See glRasterPos.
GL_CURRENT_RASTER_POSITION_VALID boolean 1 whether the current raster position is valid. See glRasterPos.
GL_CURRENT_RASTER_TEXTURE_COORDS atom 4 the s, t, r, and q current raster texture coordinates. See glRasterPos and glTexCoord.
GL_CURRENT_TEXTURE_COORDS atom 4 the s, t, r, and q current texture coordinates. See glTexCoord.
GL_DEPTH_BIAS atom 1 the depth bias factor used during pixel transfers. See glPixelTransfer.
GL_DEPTH_BITS integer 1 the number of bitplanes in the depth buffer.
GL_DEPTH_CLEAR_VALUE atom1 1 the value that is used to clear the depth buffer. See glClearDepth.
GL_DEPTH_FUNC integer 1 the symbolic constant that indicates the depth comparison function. See glDepthFunc.
GL_DEPTH_RANGE atom1 2 the near and far mapping limits for the depth buffer. See glDepthRange.
GL_DEPTH_SCALE atom 1 the depth scale factor used during pixel transfers. See glPixelTransfer.
GL_DEPTH_TEST boolean 1 whether depth testing of fragments is enabled. See glDepthFunc and glDepthRange.
GL_DEPTH_WRITEMASK boolean 1 whether the depth buffer is enabled for writing. See glDepthMask.
GL_DITHER boolean 1 whether dithering of fragment colors and indexes is enabled.
GL_DOUBLEBUFFER boolean 1 whether double buffering is supported.
GL_DRAW_BUFFER integer 1 a symbolic constant indicating which buffers are being drawn to. See glDrawBuffer.
GL_EDGE_FLAG boolean 1 whether the current edge flag is true or false. See glEdgeFlag.
GL_EDGE_FLAG_ARRAY boolean 1 whether the edge flag array is enabled. See glEdgeFlagPointer.
GL_EDGE_FLAG_ARRAY_STRIDE integer 1 the byte offset between consecutive edge flags in the edge flag array. See glEdgeFlagPointer.
GL_FOG boolean 1 whether fogging is enabled. See glFog.
GL_FOG_COLOR atom1 4 the red, green, blue, and alpha components of the fog color. See glFog.
GL_FOG_DENSITY atom 1 the fog density parameter. See glFog.
GL_FOG_END atom 1 the end factor for the linear fog equation. See glFog.
GL_FOG_HINT integer 1 a symbolic constant indicating the mode of the fog hint. See glHint.
GL_FOG_INDEX atom 1 the fog color index. See glFog.
GL_FOG_MODE atom 1 a symbolic constant indicating which fog equation is selected. See glFog.
GL_FOG_START atom 1 the start factor for the linear fog equation. See glFog.
GL_FRONT_FACE integer 1 a symbolic constant indicating whether clockwise or counterclockwise polygon winding is treated as front-facing. See glFrontFace.
GL_GREEN_BIAS atom 1 the green bias factor used during pixel transfers. See glPixelTransfer.
GL_GREEN_BITS integer 1 the number of green bitplanes in each color buffer.
GL_GREEN_SCALE atom 1 the green scale factor used during pixel transfers. See glPixelTransfer.
GL_INDEX_ARRAY boolean 1 whether the color index array is enabled. See glIndexPointer.
GL_INDEX_ARRAY_STRIDE integer 1 the byte offset between consecutive color indexes in the color index array. See glIndexPointer.
GL_INDEX_ARRAY_TYPE integer 1 the data type of indexes in the color index array. The initial value is GL_FLOAT. See glIndexPointer.
GL_INDEX_BITS integer 1 the number of bitplanes in each color-index buffer.
GL_INDEX_CLEAR_VALUE atom 1 the color index used to clear the color-index buffers. See glClearIndex.
GL_INDEX_LOGIC_OP boolean 1 whether a fragment’s index values are merged into the framebuffer using a logical operation. See glLogicOp.
GL_INDEX_MODE boolean 1 whether OpenGL is in color-index mode (TRUE) or RGBA mode (FALSE).
GL_INDEX_OFFSET integer 1 the offset added to color and stencil indexes during pixel transfers. See glPixelTransfer.
GL_INDEX_SHIFT integer 1 the amount that color and stencil indexes are shifted during pixel transfers. See glPixelTransfer.
GL_INDEX_WRITEMASK integer 1 a mask indicating which bitplanes of each color-index buffer can be written. See glIndexMask.
GL_LIGHTi boolean 1 whether the specified light is enabled. See glLight and glLightModel.
GL_LIGHTING boolean 1 whether lighting is enabled. See glLightModel.
GL_LIGHT_MODEL_AMBIENT atom1 4 the red, green, blue, and alpha components of the ambient intensity of the entire scene. See glLightModel.
GL_LIGHT_MODEL_LOCAL_VIEWER boolean 1 whether specular reflection calculations treat the viewer as being local to the scene. See glLightModel.
GL_LIGHT_MODEL_TWO_SIDE boolean 1 whether separate materials are used to compute lighting for front-facing and back-facing polygons. See glLightModel.
GL_LINE_SMOOTH boolean 1 whether antialiasing of lines is enabled. See glLineWidth.
GL_LINE_SMOOTH_HINT integer 1 a symbolic constant indicating the mode of the line antialiasing hint. See glHint.
GL_LINE_STIPPLE boolean 1 whether stippling of lines is enabled. See glLineStipple.
GL_LINE_STIPPLE_PATTERN integer 1 the 16-bit line stipple pattern. See glLineStipple.
GL_LINE_STIPPLE_REPEAT integer 1 the line stipple repeat factor. See glLineStipple.
GL_LINE_WIDTH atom 1 the line width as specified with glLineWidth.
GL_LINE_WIDTH_GRANULARITY atom 1 the width difference between adjacent supported widths for antialiased lines. See glLineWidth.
GL_LINE_WIDTH_RANGE atom 2 the smallest and largest supported widths for antialiased lines. See glLineWidth.
GL_LIST_BASE integer 1 the base offset added to all names in arrays presented to glCallLists. See glListBase.
GL_LIST_INDEX integer 1 the name of the display list currently under construction. Zero is returned if no display list is currently under construction. See glNewList.
GL_LIST_MODE integer 1 a symbolic constant indicating the construction mode of the display list currently being constructed. See glNewList.
GL_LOGIC_OP boolean 1 whether fragment indexes are merged into the framebuffer using a logical operation. See glLogicOp.
GL_LOGIC_OP_MODE integer 1 a symbolic constant indicating the selected logic operational mode. See glLogicOp.
GL_MAP1_COLOR_4 boolean 1 whether 1-D evaluation generates colors. See glMap1.
GL_MAP1_GRID_DOMAIN atom 2 the endpoints of the 1-D maps grid domain. See glMapGrid.
GL_MAP1_GRID_SEGMENTS integer 1 the number of partitions in the 1-D maps grid domain. See glMapGrid.
GL_MAP1_INDEX boolean 1 whether 1-D evaluation generates color indexes. See glMap1.
GL_MAP1_NORMAL boolean 1 whether 1-D evaluation generates normals. See glMap1.
GL_MAP1_TEXTURE_COORD_1 boolean 1 whether 1-D evaluation generates 1-D texture coordinates. See glMap1.
GL_MAP1_TEXTURE_COORD_2 boolean 1 whether 1-D evaluation generates 2-D texture coordinates. See glMap1.
GL_MAP1_TEXTURE_COORD_3 boolean 1 whether 1-D evaluation generates 3-D texture coordinates. See glMap1.
GL_MAP1_TEXTURE_COORD_4 boolean 1 whether 1-D evaluation generates 4-D texture coordinates. See glMap1.
GL_MAP1_VERTEX_3 boolean 1 whether 1-D evaluation generates 3-D vertex coordinates. See glMap1.
GL_MAP1_VERTEX_4 boolean 1 whether 1-D evaluation generates 4-D vertex coordinates. See glMap1.
GL_MAP2_COLOR_4 boolean 1 whether 2-D evaluation generates colors. See glMap2.
GL_MAP2_GRID_DOMAIN atom 4 the endpoints of the 2-D maps i and j grid domains. See glMapGrid.
GL_MAP2_GRID_SEGMENTS integer 2 the number of partitions in the 2-D maps i and j grid domains. See glMapGrid.
GL_MAP2_INDEX boolean 1 whether 2-D evaluation generates color indexes. See glMap2.
GL_MAP2_NORMAL boolean 1 whether 2-D evaluation generates normals. See glMap2.
GL_MAP2_TEXTURE_COORD_1 boolean 1 whether 2-D evaluation generates 1-D texture coordinates. See glMap2.
GL_MAP2_TEXTURE_COORD_2 boolean 1 whether 2-D evaluation generates 2-D texture coordinates. See glMap2.
GL_MAP2_TEXTURE_COORD_3 boolean 1 whether 2-D evaluation generates 3-D texture coordinates. See glMap2.
GL_MAP2_TEXTURE_COORD_4 boolean 1 whether 2-D evaluation generates 4-D texture coordinates. See glMap2.
GL_MAP2_VERTEX_3 boolean 1 whether 2-D evaluation generates 3-D vertex coordinates. See glMap2.
GL_MAP2_VERTEX_4 boolean 1 whether 2-D evaluation generates 4-D vertex coordinates. See glMap2.
GL_MAP_COLOR boolean 1 whether colors and color indexes are to be replaced by table lookup during pixel transfers. See glPixelTransfer.
GL_MAP_STENCIL boolean 1 whether stencil indexes are to be replaced by table lookup during pixel transfers. See glPixelTransfer.
GL_MATRIX_MODE integer 1 a symbolic constant indicating which matrix stack is currently the target of all matrix operations. See glMatrixMode.
GL_MAX_CLIENT_ATTRIB_STACK_DEPTH integer 1 the maximum supported depth of the client attribute stack. See glPushClientAttrib.
GL_MAX_ATTRIB_STACK_DEPTH integer 1 the maximum supported depth of the attribute stack. See glPushAttrib.
GL_MAX_CLIP_PLANES integer 1 the maximum number of application-defined clipping planes. See glClipPlane.
GL_MAX_EVAL_ORDER integer 1 the maximum equation order supported by 1-D and 2-D evaluators. See glMap1 and glMap2.
GL_MAX_LIGHTS integer 1 the maximum number of lights. See glLight.
GL_MAX_LIST_NESTING integer 1 the maximum recursion depth allowed during display-list traversal. See glCallList.
GL_MAX_MODELVIEW_STACK_DEPTH integer 1 the maximum supported depth of the modelview matrix stack. See glPushMatrix.
GL_MAX_NAME_STACK_DEPTH integer 1 the maximum supported depth of the selection name stack. See glPushName.
GL_MAX_PIXEL_MAP_TABLE integer 1 the maximum supported size of a glPixelMap lookup table.
GL_MAX_PROJECTION_STACK_DEPTH integer 1 the maximum supported depth of the projection matrix stack. See glPushMatrix.
GL_MAX_TEXTURE_SIZE integer 1 the maximum width or height of any texture image (without borders). See glTexImage1D and glTexImage2D.
GL_MAX_TEXTURE_STACK_DEPTH integer 1 the maximum supported depth of the texture matrix stack. See glPushMatrix.
GL_MAX_VIEWPORT_DIMS atom 2 the maximum supported width and height of the viewport. See glViewport.
GL_MODELVIEW_MATRIX atom 16 the modelview matrix on the top of the modelview matrix stack. See glPushMatrix.
GL_MODELVIEW_STACK_DEPTH integer 1 the number of matrices on the modelview matrix stack. See glPushMatrix.
GL_NAME_STACK_DEPTH integer 1 the number of names on the selection name stack. See glPushName.
GL_NORMAL_ARRAY boolean 1 whether the normal array is enabled. See glNormalPointer.
GL_NORMAL_ARRAY_STRIDE integer 1 the byte offset between consecutive normals in the normal array. See glNormalPointer.
GL_NORMAL_ARRAY_TYPE integer 1 the data type of each coordinate in the normal array. See glNormalPointer.
GL_NORMALIZE boolean 1 whether normals are automatically scaled to unit length after they have been transformed to eye coordinates. See glNormal.
GL_PACK_ALIGNMENT integer 1 the byte alignment used for writing pixel data to memory. See glPixelStore.
GL_PACK_LSB_FIRST boolean 1 whether single-bit pixels being written to memory are written first to the least significant bit of each unsigned byte. See glPixelStore.
GL_PACK_ROW_LENGTH integer 1 the row length used for writing pixel data to memory. See glPixelStore.
GL_PACK_SKIP_PIXELS integer 1 the number of pixel locations skipped before the first pixel is written into memory. See glPixelStore.
GL_PACK_SKIP_ROWS integer 1 the number of rows of pixel locations skipped before the first pixel is written into memory. See glPixelStore.
GL_PACK_SWAP_BYTES boolean 1 whether the bytes of 2-byte and 4-byte pixel indexes and components are swapped before being written to memory. See glPixelStore.
GL_PERSPECTIVE_CORRECTION_HINT integer 1 a symbolic constant indicating the mode of the perspective correction hint. See glHint.
GL_PIXEL_MAP_A_TO_A_SIZE integer 1 the size of the alpha-to-alpha pixel-translation table. See glPixelMap.
GL_PIXEL_MAP_B_TO_B_SIZE integer 1 the size of the blue-to-blue pixel-translation table. See glPixelMap.
GL_PIXEL_MAP_G_TO_G_SIZE integer 1 the size of the green-to-green pixel-translation table. See glPixelMap.
GL_PIXEL_MAP_I_TO_A_SIZE integer 1 the size of the index-to-alpha pixel translation table. See glPixelMap.
GL_PIXEL_MAP_I_TO_B_SIZE integer 1 the size of the index-to-blue pixel translation table. See glPixelMap.
GL_PIXEL_MAP_I_TO_G_SIZE integer 1 the size of the index-to-green pixel-translation table. See glPixelMap.
GL_PIXEL_MAP_I_TO_I_SIZE integer 1 the size of the index-to-index pixel-translation table. See glPixelMap.
GL_PIXEL_MAP_I_TO_R_SIZE integer 1 the size of the index-to-red pixel-translation table. See glPixelMap.
GL_PIXEL_MAP_R_TO_R_SIZE integer 1 the size of the red-to-red pixel-translation table. See glPixelMap.
GL_PIXEL_MAP_S_TO_S_SIZE integer 1 the size of the stencil-to-stencil pixel translation table. See glPixelMap.
GL_POINT_SIZE atom 1 the point size as specified by glPointSize.
GL_POINT_SIZE_GRANULARITY atom 1 the size difference between adjacent supported sizes for antialiased points. See glPointSize.
GL_POINT_SIZE_RANGE atom 2 the smallest and largest supported sizes for antialiased points. See glPointSize.
GL_POINT_SMOOTH boolean 1 whether antialiasing of points is enabled. See glPointSize.
GL_POINT_SMOOTH_HINT integer 1 a symbolic constant indicating the mode of the point antialiasing hint. See glHint.
GL_POLYGON_MODE integer 2 symbolic constants indicating whether front-facing and back-facing polygons are rasterized as points, lines, or filled polygons. See glPolygonMode.
GL_POLYGON_OFFSET_FACTOR atom 1 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. See glPolygonOffset.
GL_POLYGON_OFFSET_UNITS atom 1 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. See glPolygonOffset.
GL_POLYGON_OFFSET_FILL boolean 1 whether polygon offset is enabled for polygons in fill mode. See glPolygonOffset.
GL_POLYGON_OFFSET_LINE boolean 1 whether polygon offset is enabled for polygons in line mode. See glPolygonOffset.
GL_POLYGON_OFFSET_POINT boolean 1 whether polygon offset is enabled for polygons in point mode. See glPolygonOffset.
GL_POLYGON_SMOOTH boolean 1 whether antialiasing of polygons is enabled. See glPolygonMode.
GL_POLYGON_SMOOTH_HINT integer 1 a symbolic constant indicating the mode of the polygon antialiasing hint. See glHint.
GL_POLYGON_STIPPLE boolean 1 whether stippling of polygons is enabled. See glPolygonStipple.
GL_PROJECTION_MATRIX atom 16 the projection matrix on the top of the projection matrix stack. See glPushMatrix.
GL_PROJECTION_STACK_DEPTH integer 1 the number of matrices on the projection matrix stack. See glPushMatrix.
GL_READ_BUFFER integer 1 a symbolic constant indicating which color buffer is selected for reading. See glReadPixels and glAccum.
GL_RED_BIAS atom 1 the red bias factor used during pixel transfers. See glPixelTransfer.
GL_RED_BITS integer 1 the number of red bitplanes in each color buffer.
GL_RED_SCALE atom 1 the red scale factor used during pixel transfers. See glPixelTransfer.
GL_RENDER_MODE integer 1 a symbolic constant indicating whether OpenGL is in render, select, or feedback mode. See glRenderMode.
GL_RGBA_MODE boolean 1 whether OpenGL is in RGBA mode (TRUE) or color-index mode (FALSE). See glColor.
GL_SCISSOR_BOX atom 4 the x and y window coordinates of the scissor box, followed by its width and height. See glScissor.
GL_SCISSOR_TEST boolean 1 whether scissoring is enabled. See glScissor.
GL_SHADE_MODEL integer 1 a symbolic constant indicating whether the shading mode is flat or smooth. See glShadeModel.
GL_STENCIL_BITS integer 1 the number of bitplanes in the stencil buffer.
GL_STENCIL_CLEAR_VALUE integer 1 the index to which the stencil bitplanes are cleared. See glClearStencil.
GL_STENCIL_FAIL integer 1 a symbolic constant indicating what action is taken when the stencil test fails. See glStencilOp.
GL_STENCIL_FUNC integer 1 a symbolic constant indicating what function is used to compare the stencil reference value with the stencil buffer value. See glStencilFunc.
GL_STENCIL_PASS_DEPTH_FAIL integer 1 a symbolic constant indicating what action is taken when the stencil test passes, but the depth test fails. See glStencilOp.
GL_STENCIL_PASS_DEPTH_PASS integer 1 a symbolic constant indicating what action is taken when the stencil test passes and the depth test passes. See glStencilOp.
GL_STENCIL_REF integer 1 the reference value that is compared with the contents of the stencil buffer. See glStencilFunc.
GL_STENCIL_TEST boolean 1 whether stencil testing of fragments is enabled. See glStencilFunc and glStencilOp.
GL_STENCIL_VALUE_MASK integer 1 the mask that is used to mask both the stencil reference value and the stencil buffer value before they are compared. See glStencilFunc.
GL_STENCIL_WRITEMASK integer 1 the mask that controls writing of the stencil bitplanes. See glStencilMask.
GL_STEREO boolean 1 whether stereo buffers (left and right) are supported.
GL_SUBPIXEL_BITS integer 1 an estimate of the number of bits of subpixel resolution that are used to position rasterized geometry in window coordinates.
GL_TEXTURE_1D boolean 1 whether 1-D texture mapping is enabled. See glTexImage1D.
GL_TEXTURE_2D boolean 1 whether 2-D texture mapping is enabled. See glTexImage2D.
GL_TEXTURE_COORD_ARRAY boolean 1 whether the texture coordinate array is enabled. See glTexCoordPointer.
GL_TEXTURE_COORD_ARRAY_SIZE integer 1 the number of coordinates per element in the texture coordinate array. See glTexCoordPointer.
GL_TEXTURE_COORD_ARRAY_STRIDE integer 1 the byte offset between consecutive elements in the texture coordinate array. See glTexCoordPointer.
GL_TEXTURE_COORD_ARRAY_TYPE integer 1 the data type of the coordinates in the texture coordinate array. See glTexCoordPointer.
GL_TEXTURE_ENV_COLOR atom1 4 the red, green, blue, and alpha values of the texture environment color. See glTexEnv.
GL_TEXTURE_ENV_MODE integer 1 a symbolic constant indicating which texture environment function is currently selected. See glTexEnv.
GL_TEXTURE_GEN_Q boolean 1 whether automatic generation of the Q texture coordinate is enabled. See glTexGen.
GL_TEXTURE_GEN_R boolean 1 whether automatic generation of the R texture coordinate is enabled. See glTexGen.
GL_TEXTURE_GEN_S boolean 1 whether automatic generation of the S texture coordinate is enabled. See glTexGen.
GL_TEXTURE_GEN_T boolean 1 whether automatic generation of the T texture coordinate is enabled. See glTexGen.
GL_TEXTURE_MATRIX atom 16 the texture matrix on the top of the texture matrix stack. See glPushMatrix.
GL_TEXTURE_STACK_DEPTH integer 1 the number of matrices on the texture matrix stack. See glPushMatrix.
GL_UNPACK_ALIGNMENT integer 1 the byte alignment used for reading pixel data from memory. See glPixelStore.
GL_UNPACK_LSB_FIRST boolean 1 whether single-bit pixels being read from memory are read first from the least significant bit of each unsigned byte. See glPixelStore.
GL_UNPACK_ROW_LENGTH integer 1 the row length used for reading pixel data from memory. See glPixelStore.
GL_UNPACK_SKIP_PIXELS integer 1 the number of pixel locations skipped before the first pixel is read from memory. See glPixelStore.
GL_UNPACK_SKIP_ROWS integer 1 the number of rows of pixel locations skipped before the first pixel is read from memory. See glPixelStore.
GL_UNPACK_SWAP_BYTES boolean 1 whether the bytes of 2-byte and 4-byte pixel indexes and components are swapped after being read from memory. See glPixelStore.
GL_VERTEX_ARRAY boolean 1 whether the vertex array is enabled. See glVertexPointer.
GL_VERTEX_ARRAY_SIZE integer 1 the number of coordinates per vertex in the vertex array. See glVertexPointer.
GL_VERTEX_ARRAY_STRIDE integer 1 the byte offset between consecutive vertexes in the vertex array. See glVertexPointer.
GL_VERTEX_ARRAY_TYPE integer 1 the data type of each coordinate in the vertex array. See glVertexPointer.
GL_VIEWPORT atom 4 the x and y window coordinates of the viewport, followed by its width and height. See glViewport.
GL_ZOOM_X atom 1 the x pixel zoom factor. See glPixelZoom.
GL_ZOOM_Y atom 1 the y pixel zoom factor. See glPixelZoom.


Note the type column is entirely my own devising, possibly misleading, constructed by manually/laboriously substituting "The params parameter returns" etc.
1 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 following error codes can be retrieved by the glGetError function.
GL_INVALID_ENUM - pname was not an accepted value.
GL_INVALID_OPERATION - glGetXxxv was called between a call to glBegin and the corresponding call to glEnd.
Remarks These routines retrieve values for simple state variables in OpenGL.
Type conversion is performed if params has a different type from the state variable value being requested.
If you call glGetBooleanv, a floating-point or integer value is converted to GL_FALSE if and only if it is zero. Otherwise, it is converted to GL_TRUE.
If you call glGetIntegerv, 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 you call glGetFloatv or glGetDoublev, Boolean values are returned as GL_TRUE or GL_FALSE, and integer values are converted to floating-point values.
You can query many of the Boolean parameters more easily with glIsEnabled.
See Also:
DEV See also glAccum glAlphaFunc glBegin, glBlendFunc glCallList glClearAccum glClearColor glClearDepth glClearIndex glClearStencil glClipPlane glColor glColorMask glColorMaterial glCullFace glDepthFunc glDepthMask glDepthRange glDrawBuffer glEdgeFlag glEnd, glFog glFrontFace glGetClipPlane glGetError glGetLight glGetMap glGetMaterial glGetPixelMap glGetPolygonStipple glGetString glGetTexEnv glGetTexGen glGetTexImage glGetTexLevelParameter glGetTexParameter glHint glIndex glIndexMask glIsEnabled glLight glLightModel glLineStipple glLineWidth glListBase glLogicOp glMap1 glMap2 glMapGrid glMatrixMode glNewList glNormal, glPixelMap glPixelStore glPixelTransfer glPixelZoom glPointSize glPolygonMode glPolygonStipple glPushAttrib glPushMatrix glPushName glRasterPos glReadPixels glScissor glShadeModel glStencilFunc glStencilMask glStencilOp glTexCoord glTexEnv glTexGen glTexImage1D glTexImage2D glViewport