GLENABLE

Section: Misc. Reference Manual Pages (3G)
Index Return to Main Contents
 

NAME

glEnable, glDisable - enable or disable server-side 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. The initial value for each capability with the
exception of GL_DITHER is GL_FALSE. The initial value for
GL_DITHER is GL_TRUE. 

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,
generate normal vectors 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_LOGIC_OP

If enabled,
apply the currently selected logical operation to the incoming RGBA
color and color buffer values. See glLogicOp.

GL_COLOR_MATERIAL

If enabled,
have one or more material parameters track the current color.
See glColorMaterial.

GL_COLOR_TABLE

If enabled,
preform a color table lookup on the incoming RGBA color values.
See glColorTable.

GL_CONVOLUTION_1D

If enabled,
perform a 1D convolution operation on incoming RGBA color values.
See glConvolutionFilter1D.

GL_CONVOLUTION_2D

If enabled,
perform a 2D convolution operation on incoming RGBA color values.
See glConvolutionFilter2D.

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. Note that even if
the depth buffer exists and the depth mask is non-zero, the 
depth buffer is not updated if the depth test is disabled. See
glDepthFunc and 



glDepthRange. 

GL_DITHER       

If enabled,

dither color components or indices before they are written to the
color buffer.

GL_FOG

If enabled,
blend a fog color into the posttexturing color.
See glFog.

GL_HISTOGRAM

If enabled,
histogram incoming RGBA color values.
See glHistogram.

GL_INDEX_LOGIC_OP

If enabled,
apply the currently selected logical operation to the incoming index and color
buffer indices. See 



glLogicOp.

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_MAP1_COLOR_4

If enabled,
calls to
glEvalCoord1,
glEvalMesh1, and
glEvalPoint1 generate RGBA values.
See glMap1.

GL_MAP1_INDEX

If enabled,
calls to
glEvalCoord1,
glEvalMesh1, and
glEvalPoint1 generate color indices.
See glMap1.

GL_MAP1_NORMAL

If enabled,
calls to
glEvalCoord1,
glEvalMesh1, and
glEvalPoint1 generate normals.
See glMap1.

GL_MAP1_TEXTURE_COORD_1

If enabled,
calls to
glEvalCoord1,
glEvalMesh1, and
glEvalPoint1 generate
s
texture coordinates.
See glMap1.

GL_MAP1_TEXTURE_COORD_2

If enabled,
calls to
glEvalCoord1,
glEvalMesh1, and
glEvalPoint1 generate
s and
t texture coordinates.
See glMap1.

GL_MAP1_TEXTURE_COORD_3

If enabled,
calls to
glEvalCoord1,
glEvalMesh1, and
glEvalPoint1 generate
s,
t, and
r texture coordinates.
See glMap1.

GL_MAP1_TEXTURE_COORD_4

If enabled,
calls to
glEvalCoord1,
glEvalMesh1, and
glEvalPoint1 generate
s,
t,
r, and
q texture coordinates.
See glMap1.

GL_MAP1_VERTEX_3

If enabled,
calls to
glEvalCoord1,
glEvalMesh1, and
glEvalPoint1 generate
x, y, and z vertex coordinates.
See glMap1.

GL_MAP1_VERTEX_4

If enabled,
calls to
glEvalCoord1,
glEvalMesh1, and
glEvalPoint1 generate
homogeneous
x,
y,
z, and
w vertex coordinates.
See glMap1.

GL_MAP2_COLOR_4

If enabled,
calls to
glEvalCoord2,
glEvalMesh2, and
glEvalPoint2 generate RGBA values.
See glMap2.

GL_MAP2_INDEX

If enabled,
calls to
glEvalCoord2,
glEvalMesh2, and
glEvalPoint2 generate color indices.
See glMap2.

GL_MAP2_NORMAL

If enabled,
calls to
glEvalCoord2,
glEvalMesh2, and
glEvalPoint2 generate normals.
See glMap2.

GL_MAP2_TEXTURE_COORD_1

If enabled,
calls to
glEvalCoord2,
glEvalMesh2, and
glEvalPoint2 generate
s
texture coordinates.
See glMap2.

GL_MAP2_TEXTURE_COORD_2

If enabled,
calls to
glEvalCoord2,
glEvalMesh2, and
glEvalPoint2 generate
s and
t texture coordinates.
See glMap2.

GL_MAP2_TEXTURE_COORD_3

If enabled,
calls to
glEvalCoord2,
glEvalMesh2, and
glEvalPoint2 generate
s,
t, and
r texture coordinates.
See glMap2.

GL_MAP2_TEXTURE_COORD_4

If enabled,
calls to
glEvalCoord2,
glEvalMesh2, and
glEvalPoint2 generate
s,
t,
r, and
q texture coordinates.
See glMap2.

GL_MAP2_VERTEX_3

If enabled,
calls to
glEvalCoord2,
glEvalMesh2, and
glEvalPoint2 generate
x, y, and z vertex coordinates.
See glMap2.

GL_MAP2_VERTEX_4

If enabled,
calls to
glEvalCoord2,
glEvalMesh2, and
glEvalPoint2 generate
homogeneous
x,
y,
z, and
w vertex coordinates.
See glMap2.

GL_MINMAX

If enabled,
compute the minimum and maximum values of incoming RGBA color values.
See glMinmax.

GL_NORMALIZE

If enabled,
normal vectors specified with glNormal are scaled to unit length
after transformation. See glNormal.

GL_POINT_SMOOTH

If enabled,
draw points with proper filtering.
Otherwise,
draw aliased points.
See glPointSize.

GL_POLYGON_OFFSET_FILL

If enabled, and if the polygon is rendered in
GL_FILL mode, an offset is added to depth values of a polygon's
fragments before the depth comparison is performed. 
See glPolygonOffset. 

GL_POLYGON_OFFSET_LINE

If enabled, and if the polygon is rendered in
GL_LINE mode, an offset is added to depth values of a polygon's
fragments before the depth comparison is performed. See glPolygonOffset. 

GL_POLYGON_OFFSET_POINT

If enabled, an offset is added to depth values of a polygon's fragments
before the depth comparison is performed, if the polygon is rendered in 
GL_POINT mode. See glPolygonOffset. 

GL_POLYGON_SMOOTH

If enabled, draw polygons with proper filtering.
Otherwise, draw aliased polygons. For correct anti-aliased polygons,
an alpha buffer is needed and the polygons must be sorted front to
back. 

GL_POLYGON_STIPPLE

If enabled,
use the current polygon stipple pattern when rendering
polygons. See glPolygonStipple.

GL_POST_COLOR_MATRIX_COLOR_TABLE

If enabled,
preform a color table lookup on RGBA color values after color matrix 
transformation.
See glColorTable.

GL_POST_CONVOLUTION_COLOR_TABLE

If enabled,
preform a color table lookup on RGBA color values after convolution.
See glColorTable.

GL_RESCALE_NORMAL

If enabled, normal vectors specified with glNormal are scaled to
unit length after transformation. See glNormal.

GL_SEPARABLE_2D

If enabled, perform a two-dimensional convolution operation using a separable
convolution filter on incoming RGBA color values.
See glSeparableFilter2D.

GL_SCISSOR_TEST

If enabled,
discard fragments that are outside the scissor rectangle. 
See glScissor.

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- or three-dimensional texturing is also enabled).
See glTexImage1D.

GL_TEXTURE_2D

If enabled, two-dimensional texturing is performed
(unless three-dimensional texturing is also enabled). See glTexImage2D.

GL_TEXTURE_3D

If enabled, three-dimensional texturing is performed. See glTexImage3D.

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.

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.


 

NOTES


GL_POLYGON_OFFSET_FILL, GL_POLYGON_OFFSET_LINE,
GL_POLYGON_OFFSET_POINT,
GL_COLOR_LOGIC_OP, and GL_INDEX_LOGIC_OP are available
only if the GL version is 1.1 or greater. 

GL_RESCALE_NORMAL, and GL_TEXTURE_3D are available only if the
GL version is 1.2 or greater.

GL_COLOR_TABLE, GL_CONVOLUTION_1D, GL_CONVOLUTION_2D,
GL_HISTOGRAM, GL_MINMAX,
GL_POST_COLOR_MATRIX_COLOR_TABLE,
GL_POST_CONVOLUTION_COLOR_TABLE, and
GL_SEPARABLE_2D are available only if GL_ARB_imaging is returned
from glGet with an argument of GL_EXTENSIONS.

If GL_ARB_multitexture is supported, GL_TEXTURE_1D,
GL_TEXTURE_2D, GL_TEXTURE_3D, GL_TEXTURE_GEN_S,
GL_TEXTURE_GEN_T, GL_TEXTURE_GEN_R, and GL_TEXTURE_GEN_Q
enable or disable the respective state for the active texture unit
specified with glActiveTextureARB.
 

ERRORS


GL_INVALID_ENUM is generated if cap is not one of the values
listed previously.

GL_INVALID_OPERATION is generated if glEnable or glDisable
is executed between the execution of glBegin
and the corresponding execution of glEnd.
 

SEE ALSO


glActiveTextureARB(3G),
glAlphaFunc(3G),
glBlendFunc(3G),
glClipPlane(3G),
glColorMaterial(3G),
glCullFace(3G),
glDepthFunc(3G),
glDepthRange(3G),
glEnableClientState(3G),
glFog(3G),
glGet(3G),
glIsEnabled(3G),
glLight(3G),
glLightModel(3G),
glLineWidth(3G),
glLineStipple(3G),
glLogicOp(3G),
glMap1(3G),
glMap2(3G),
glMaterial(3G),
glNormal(3G),
glPointSize(3G),
glPolygonMode(3G),
glPolygonOffset(3G),
glPolygonStipple(3G),
glScissor(3G),
glStencilFunc(3G),
glStencilOp(3G),
glTexGen(3G),
glTexImage1D(3G),
glTexImage2D(3G),
glTexImage3D(3G)