1991-2006
Silicon Graphics, Inc.
glEnable
3G
glEnable
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.
C Specification
void glEnablei
GLenum cap
GLuint index
Parameters
cap
Specifies a symbolic constant indicating a GL capability.
index
Specifies the index of the swtich to enable.
C Specification
void glDisablei
GLenum cap
GLuint index
Parameters
cap
Specifies a symbolic constant indicating a GL capability.
index
Specifies the index of the swtich to disable.
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 and GL_MULTISAMPLE is
GL_FALSE. The initial value for
GL_DITHER and GL_MULTISAMPLE is GL_TRUE.
Both glEnable and glDisable take a single argument, cap,
which can assume one of the following values:
Some of the GL's capabilities are indicated. glEnablei and glDisablei enable and disable
indexed capabilities.
GL_BLEND
If enabled,
blend the computed fragment color values with the values in the color
buffers. See glBlendFunc.
GL_CLIP_DISTANCEi
If enabled, clip geometry against user-defined half space i.
GL_COLOR_LOGIC_OP
If enabled,
apply the currently selected logical operation to the computed fragment
color and color buffer values. See glLogicOp.
GL_CULL_FACE
If enabled,
cull polygons based on their winding in window coordinates.
See glCullFace.
GL_DEPTH_CLAMP
If enabled,
the
-wc≤zc≤wc
plane equation is ignored by view volume clipping (effectively, there is no near or
far plane clipping).
See glDepthRange.
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_LINE_SMOOTH
If enabled,
draw lines with correct filtering.
Otherwise,
draw aliased lines.
See glLineWidth.
GL_MULTISAMPLE
If enabled,
use multiple fragment samples in computing the final color of a pixel.
See glSampleCoverage.
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 antialiased polygons,
an alpha buffer is needed and the polygons must be sorted front to
back.
GL_PRIMITIVE_RESTART
Enables primitive restarting. If enabled, any one of the draw commands
which transfers a set of generic attribute array elements to the GL will restart
the primitive when the index of the vertex is equal to the primitive restart index.
See glPrimitiveRestartIndex.
GL_SAMPLE_ALPHA_TO_COVERAGE
If enabled,
compute a temporary coverage value where each bit is determined by the
alpha value at the corresponding sample location. The temporary coverage
value is then ANDed with the fragment coverage value.
GL_SAMPLE_ALPHA_TO_ONE
If enabled,
each sample alpha value is replaced by the maximum representable alpha value.
GL_SAMPLE_COVERAGE
If enabled,
the fragment's coverage is ANDed with the temporary coverage value. If
GL_SAMPLE_COVERAGE_INVERT is set to GL_TRUE, invert the coverage
value.
See glSampleCoverage.
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_CUBE_MAP_SEAMLESS
If enabled, modifies the way sampling is performed on cube map textures. See the spec for more information.
GL_PROGRAM_POINT_SIZE
If enabled
and a vertex or geometry shader is active, then the derived point size is taken from the (potentially clipped) shader builtin
gl_PointSize and clamped to the implementation-dependent point size range.
Errors
GL_INVALID_ENUM is generated if cap is not one of the values
listed previously.
GL_INVALID_VALUE is generated by glEnablei and glDisablei
if index is greater than or equal to the number of indexed capabilities for cap.
Notes
GL_PRIMITIVE_RESTART is available only if the GL version is 3.1 or greater.
GL_TEXTURE_CUBE_MAP_SEAMLESS is available only if the GL version is 3.2 or greater.
Any token accepted by glEnable or glDisable is also accepted by
glEnablei and glDisablei, but if the capability is not indexed,
the maximum value that index may take is zero.
In general, passing an indexed capability to glEnable or glDisable
will enable or disable that capability for all indices, resepectively.
Associated Gets
glIsEnabled
glGet
See Also
glActiveTexture,
glBlendFunc,
glCullFace,
glDepthFunc,
glDepthRange,
glGet,
glIsEnabled,
glLineWidth,
glLogicOp,
glPointSize,
glPolygonMode,
glPolygonOffset,
glSampleCoverage,
glScissor,
glStencilFunc,
glStencilOp,
glTexImage1D,
glTexImage2D,
glTexImage3D
Copyright
Copyright 1991-2006
Silicon Graphics, Inc. Copyright 2010 Khronos Group.
This document is licensed under the SGI
Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.