NAME

       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 indexed.  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_DEBUG_OUTPUT

           If enabled, debug messages are produced by a debug context. When disabled, the debug
           message log is silenced. Note that in a non-debug context, very few, if any messages
           might be produced, even when GL_DEBUG_OUTPUT is enabled.

       GL_DEBUG_OUTPUT_SYNCHRONOUS

           If enabled, debug messages are produced synchronously by a debug context. If disabled,
           debug messages may be produced asynchronously. In particular, they may be delayed
           relative to the execution of GL commands, and the debug callback function may be
           called from a thread other than that in which the commands are executed. See
           glDebugMessageCallback().

       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_FRAMEBUFFER_SRGB

           If enabled and the value of GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING for the
           framebuffer attachment corresponding to the destination buffer is GL_SRGB, the R, G,
           and B destination color values (after conversion from fixed-point to floating-point)
           are considered to be encoded for the sRGB color space and hence are linearized prior
           to their use in blending.

       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_PRIMITIVE_RESTART_FIXED_INDEX

           Enables primitive restarting with a fixed index. 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 fixed primitive
           index for the specified index type. The fixed index is equal to 2n−1 where n is equal
           to 8 for GL_UNSIGNED_BYTE, 16 for GL_UNSIGNED_SHORT and 32 for GL_UNSIGNED_INT.

       GL_RASTERIZER_DISCARD

           If enabled, primitives are discarded after the optional transform feedback stage, but
           before rasterization. Furthermore, when enabled, glClear(), glClearBufferData(),
           glClearBufferSubData(), glClearTexImage(), and glClearTexSubImage() are ignored.

       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_SAMPLE_SHADING

           If enabled, the active fragment shader is run once for each covered sample, or at
           fraction of this rate as determined by the current value of
           GL_MIN_SAMPLE_SHADING_VALUE. See glMinSampleShading().

       GL_SAMPLE_MASK

           If enabled, the sample coverage mask generated for a fragment during rasterization
           will be ANDed with the value of GL_SAMPLE_MASK_VALUE before shading occurs. See
           glSampleMaski().

       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, cubemap textures are sampled such that when linearly sampling from the
           border between two adjacent faces, texels from both faces are used to generate the
           final sample value. When disabled, texels from only a single face are used to
           construct the final sample value.

       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.

       GL_PRIMITIVE_RESTART_FIXED_INDEX is available only if the GL version is 4.3 or greater.

       GL_DEBUG_OUTPUT and GL_DEBUG_OUTPUT_SYNCHRONOUS are available only if the GL version is
       4.3 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 © 2010-2011 Khronos Group. This
       document is licensed under the SGI Free Software B License. For details, see
       http://oss.sgi.com/projects/FreeB/.

AUTHORS

       opengl.org