glenable - Man Page
glEnable(3G) OpenGL Reference glEnable(3G)
NAME
glEnable, glDisable - enable or disable GL capabilities
C SPECIFICATION
void glEnable( GLenum cap )
PARAMETERS
cap Specifies a symbolic constant indicating a GL capability.
C SPECIFICATION
void glDisable( GLenum cap )
PARAMETERS
cap Specifies a symbolic constant indicating a GL capability.
DESCRIPTION
glEnable and glDisable enable and disable various capabilities. Use
glIsEnabled or glGet to determine the current setting of any capability.
Both glEnable and glDisable take a single argument, cap, which can assume
one of the following values:
GL_ALPHA_TEST If enabled, do alpha testing. See glAlphaFunc.
GL_AUTO_NORMAL If enabled, compute surface normal vectors
analytically when either GL_MAP2_VERTEX_3 or
GL_MAP2_VERTEX_4 is used to generate vertices.
See glMap2.
GL_BLEND If enabled, blend the incoming RGBA color values
with the values in the color buffers. See
glBlendFunc.
GL_CLIP_PLANEi If enabled, clip geometry against user-defined
clipping plane i. See glClipPlane.
GL_COLOR_ARRAY_EXT If enabled, glArrayElementEXT and
glDrawArraysEXT will transfer colors from the
array supplied to glColorPointerEXT. See
glColorPointerEXT.
GL_COLOR_MATERIAL If enabled, have one or more material parameters
track the current color. See glColorMaterial.
GL_COLOR_TABLE_SGI If enabled, the colors produced by the pixel
transfer operation are mapped by a lookup table
before being used by convolution. See
glColorTableSGI.
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glEnable(3G) OpenGL Reference glEnable(3G)
GL_CONVOLUTION_1D_EXT If enabled, perform one-dimensional convolution
during pixel transfers. See
glConvolutionFilter1DEXT.
GL_CONVOLUTION_2D_EXT If enabled, perform two-dimensional convolution
during pixel transfers. See
glConvolutionFilter2DEXT.
GL_CULL_FACE If enabled, cull polygons based on their winding
in window coordinates. See glCullFace.
GL_DEPTH_TEST If enabled, do depth comparisons and update the
depth buffer. See glDepthFunc and
glDepthRange.
GL_DITHER If enabled, dither color components or indices
before they are written to the color buffer.
GL_EDGE_FLAG_ARRAY_EXT If enabled, glArrayElementEXT and
glDrawArraysEXT will transfer edge flags from
the array supplied to glEdgeFlagPointerEXT. See
glEdgeFlagPointerEXT.
GL_FOG If enabled, blend a fog color into the
posttexturing color. See glFog.
GL_FOG_OFFSET_SGIX If enabled, apply an offset to the Z value used
for computing fog. See glFog.
GL_HISTOGRAM_EXT If enabled, compute a histogram during pixel
transfers. See glHistogramEXT.
GL_INDEX_ARRAY_EXT If enabled, glArrayElementEXT and
glDrawArraysEXT will transfer color indices from
the array supplied to glIndexPointerEXT. See
glIndexPointerEXT.
GL_INTERLACE_SGIX If enabled, modifies the behavior of
glDrawPixels, glCopyPixels, glTexImage2D,
glTexSubImage2DEXT, glCopyTexImage2DEXT and
glCopyTexSubImage2DEXT, such that the source
image is considered to be a field of an
"interlaced" frame. That is, the effective
source image has height equal to twice the
original height, with rows (0,2,4,...)
corresponding to rows (0,1,2,...) of original
source image, and rows (1,3,5,...) made of
"transparent" pixels that do not affect the
corresponding destination pixels in the target
image. Thus, two successive operations can be
used to assemble a complete frame by interlacing
two fields. See the reference pages for the
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glEnable(3G) OpenGL Reference glEnable(3G)
above commands for more details.
GL_LIGHTi If enabled, include light i in the evaluation of
the lighting equation. See glLightModel and
glLight.
GL_LIGHTING If enabled, use the current lighting parameters
to compute the vertex color or index.
Otherwise, simply associate the current color or
index with each vertex. See glMaterial,
glLightModel, and glLight.
GL_LINE_SMOOTH If enabled, draw lines with correct filtering.
Otherwise, draw aliased lines. See glLineWidth.
GL_LINE_STIPPLE If enabled, use the current line stipple pattern
when drawing lines. See glLineStipple.
GL_LOGIC_OP If enabled, apply the currently selected logical
operation to the incoming and color buffer
indices. See glLogicOp.
GL_MAP1_COLOR_4 If enabled, calls to glEvalCoord1, glEvalMesh1,
and glEvalPoint1 will generate RGBA values. See
glMap1.
GL_MAP1_INDEX If enabled, calls to glEvalCoord1, glEvalMesh1,
and glEvalPoint1 will generate color indices.
See glMap1.
GL_MAP1_NORMAL If enabled, calls to glEvalCoord1, glEvalMesh1,
and glEvalPoint1 will generate normals. See
glMap1.
GL_MAP1_TEXTURE_COORD_1 If enabled, calls to glEvalCoord1, glEvalMesh1,
and glEvalPoint1 will generate s texture
coordinates. See glMap1.
GL_MAP1_TEXTURE_COORD_2 If enabled, calls to glEvalCoord1, glEvalMesh1,
and glEvalPoint1 will generate s and t texture
coordinates. See glMap1.
GL_MAP1_TEXTURE_COORD_3 If enabled, calls to glEvalCoord1, glEvalMesh1,
and glEvalPoint1 will generate s, t, and r
texture coordinates. See glMap1.
GL_MAP1_TEXTURE_COORD_4 If enabled, calls to glEvalCoord1, glEvalMesh1,
and glEvalPoint1 will generate s, t, r, and q
texture coordinates. See glMap1.
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glEnable(3G) OpenGL Reference glEnable(3G)
GL_MAP1_VERTEX_3 If enabled, calls to glEvalCoord1, glEvalMesh1,
and glEvalPoint1 will generate will generate x,
y, and z vertex coordinates. See glMap1.
GL_MAP1_VERTEX_4 If enabled, calls to glEvalCoord1, glEvalMesh1,
and glEvalPoint1 will generate homogeneous x, y,
z, and w vertex coordinates. See glMap1.
GL_MAP2_COLOR_4 If enabled, calls to glEvalCoord2, glEvalMesh2,
and glEvalPoint2 will generate RGBA values. See
glMap2.
GL_MAP2_INDEX If enabled, calls to glEvalCoord2, glEvalMesh2,
and glEvalPoint2 will generate color indices.
See glMap2.
GL_MAP2_NORMAL If enabled, calls to glEvalCoord2, glEvalMesh2,
and glEvalPoint2 will generate normals. See
glMap2.
GL_MAP2_TEXTURE_COORD_1 If enabled, calls to glEvalCoord2, glEvalMesh2,
and glEvalPoint2 will generate s texture
coordinates. See glMap2.
GL_MAP2_TEXTURE_COORD_2 If enabled, calls to glEvalCoord2, glEvalMesh2,
and glEvalPoint2 will generate s and t texture
coordinates. See glMap2.
GL_MAP2_TEXTURE_COORD_3 If enabled, calls to glEvalCoord2, glEvalMesh2,
and glEvalPoint2 will generate s, t, and r
texture coordinates. See glMap2.
GL_MAP2_TEXTURE_COORD_4 If enabled, calls to glEvalCoord2, glEvalMesh2,
and glEvalPoint2 will generate s, t, r, and q
texture coordinates. See glMap2.
GL_MAP2_VERTEX_3 If enabled, calls to glEvalCoord2, glEvalMesh2,
and glEvalPoint2 will generate will generate x,
y, and z vertex coordinates. See glMap2.
GL_MAP2_VERTEX_4 If enabled, calls to glEvalCoord2, glEvalMesh2,
and glEvalPoint2 will generate homogeneous x, y,
z, and w vertex coordinates. See glMap2.
GL_MINMAX_EXT If enabled, compute the minimum and maximum
values of each color component during pixel
transfers. See glMinmaxEXT.
GL_MULTISAMPLE_SGIS If enabled, perform multisampling of fragments
for single-pass antialiasing and other effects.
See glSampleMaskSGIS and glSamplePatternSGIS.
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glEnable(3G) OpenGL Reference glEnable(3G)
GL_NORMAL_ARRAY_EXT If enabled, glArrayElementEXT and
glDrawArraysEXT will transfer surface normals
from the array supplied to glNormalPointerEXT.
See glNormalPointerEXT.
GL_NORMALIZE If enabled, normal vectors specified with
glNormal are scaled to unit length after
transformation. See glNormal.
GL_POLYGON_OFFSET_EXT If enabled, an offset is added to z values of a
polygon's fragments before the depth comparison
is performed.
GL_POINT_SMOOTH If enabled, draw points with proper filtering.
Otherwise, draw aliased points. See
glPointSize.
GL_POLYGON_SMOOTH If enabled, draw polygons with proper filtering.
Otherwise, draw aliased polygons. See
glPolygonMode.
GL_POLYGON_STIPPLE If enabled, use the current polygon stipple
pattern when rendering polygons. See
glPolygonStipple.
GL_POST_COLOR_MATRIX_COLOR_TABLE_SGI
If enabled, the colors produced by the color
matrix operation are mapped by a lookup table
before being used by the histogram operation.
See glColorTableSGI.
GL_POST_CONVOLUTION_COLOR_TABLE_SGI
If enabled, the colors produced by convolution
are mapped by a lookup table before being used
by the color matrix operation. See
glColorTableSGI.
GL_REFERENCE_PLANE_SGIX If enabled, depth values for pixel fragments are
computed from a reference plane rather than from
the primitive being drawn. See
glReferencePlaneSGIX.
GL_SAMPLE_ALPHA_TO_MASK_SGIS
If enabled, convert fragment alpha values to
multisample coverage modification masks. See
glSampleMaskSGIS.
GL_SAMPLE_ALPHA_TO_ONE_SGIS
If enabled, set fragment alpha to the maximum
permissible value after computing multisample
coverage modification masks. See
glSampleMaskSGIS.
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glEnable(3G) OpenGL Reference glEnable(3G)
GL_SAMPLE_MASK_SGIS If enabled, apply a mask to modify fragment
coverage during multisampling. See
glSampleMaskSGIS.
GL_SCISSOR_TEST If enabled, discard fragments that are outside
the scissor rectangle. See glScissor.
GL_SEPARABLE_2D_EXT If enabled, perform separable two-dimensional
convolution during pixel transfers. See
glSeparableFilter2DEXT.
GL_STENCIL_TEST If enabled, do stencil testing and update the
stencil buffer. See glStencilFunc and
glStencilOp.
GL_TEXTURE_1D If enabled, one-dimensional texturing is
performed (unless two-dimensional texturing is
also enabled). See glTexImage1D.
GL_TEXTURE_2D If enabled, two-dimensional texturing is
performed. See glTexImage2D.
GL_TEXTURE_3D_EXT If enabled, three-dimensional texturing is
performed. See glTexImage3DEXT.
GL_TEXTURE_COLOR_TABLE_SGI
If enabled, the colors produced by texturing are
mapped by a lookup table before being used to
generate pixel fragments. See glColorTableSGI.
GL_TEXTURE_COORD_ARRAY_EXT
If enabled, glArrayElementEXT and
glDrawArraysEXT will transfer texture
coordinates from the array supplied to
glTexCoordPointerEXT. See glTexCoordPointerEXT.
GL_TEXTURE_GEN_Q If enabled, the q texture coordinate is computed
using the texture generation function defined
with glTexGen. Otherwise, the current q texture
coordinate is used. See glTexGen.
GL_TEXTURE_GEN_R If enabled, the r texture coordinate is computed
using the texture generation function defined
with glTexGen. Otherwise, the current r texture
coordinate is used. See glTexGen.
GL_TEXTURE_GEN_S If enabled, the s texture coordinate is computed
using the texture generation function defined
with glTexGen. Otherwise, the current s texture
coordinate is used. See glTexGen.
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glEnable(3G) OpenGL Reference glEnable(3G)
GL_TEXTURE_GEN_T If enabled, the t texture coordinate is computed
using the texture generation function defined
with glTexGen. Otherwise, the current t texture
coordinate is used. See glTexGen.
GL_VERTEX_ARRAY_EXT If enabled, glArrayElementEXT and
glDrawArraysEXT will transfer vertex coordinates
from the array supplied to glVertexPointerEXT.
See glVertexPointerEXT.
ERRORS
GL_INVALID_ENUM is generated if cap is not one of the values listed
above.
GL_INVALID_OPERATION is generated if glEnable or glDisable is executed
between the execution of glBegin and the corresponding execution of
glEnd.
MACHINE DEPENDENCIES
GL_COLOR_TABLE_SGI, GL_POST_COLOR_MATRIX_COLOR_TABLE_SGI and
GL_POST_CONVOLUTION_COLOR_TABLE_SGI are part of the SGI_color_table
extension which is not supported on RealityEngine, RealityEngine2, and
VTX systems.
The SGIX_interlace extension is supported only on InfiniteReality systems
and on RealityEngine, RealityEngine2, and VTX systems.
On RealityEngine, RealityEngine2, and VTX systems, do not enable or
disable GL_VERTEX_ARRAY_EXT, GL_NORMAL_ARRAY_EXT, GL_COLOR_ARRAY_EXT,
GL_INDEX_ARRAY_EXT, GL_TEXTURE_COORD_ARRAY_EXT, or GL_EDGE_FLAG_ARRAY_EXT
between a call to glNewList and the corresponding call to glEndList.
Instead, enable or disable before the call to glNewList.
SEE ALSO
glAlphaFunc, glBlendFunc, glClipPlane, glColorMaterial,
glConvolutionFilter1DEXT, glConvolutionFilter2DEXT, glCullFace,
glDepthFunc, glDepthRange, glFog, glGet, glHistogramEXT, glIsEnabled,
glLight, glLightModel, glLineWidth, glLineStipple, glLogicOp, glMap1,
glMap2, glMaterial, glMinmaxEXT, glNormal, glPointSize, glPolygonMode,
glPolygonOffsetEXT, glPolygonStipple, glReferencePlaneSGIX, glSampleMask,
glScissor, glSeparableFilter2DEXT, glStencilFunc, glStencilOp, glTexGen,
glTexImage1D, glTexImage2D, glTexImage3DEXT
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