- test whether a capability is enabled



C SPECIFICATION


PARAMETERS

       _param1  Specifies  a  symbolic  constant  indicating a GL
                capability.


DESCRIPTION

       glIsEnabled returns GL_TRUE if _param1 is an enabled capa-
       bility  and  returns  GL_FALSE  otherwise.   Initially all
       capabilities except GL_DITHER are disabled;  GL_DITHER  is
       initially enabled.

       The following capabilities are accepted for _param1:


       ---------------------------------------------------------------------
       Constant                           See
       ---------------------------------------------------------------------
       GL_ALPHA_TEST                      glAlphaFunc
       GL_AUTO_NORMAL                     glEvalCoord
       GL_BLEND                           glBlendFunc, glLogicOp
       GL_CLIP_PLANEi                     glClipPlane
       GL_COLOR_ARRAY                     glColorPointer
       GL_COLOR_LOGIC_OP                  glLogicOp
       GL_COLOR_MATERIAL                  glColorMaterial
       GL_COLOR_TABLE                     glColorTable
       GL_CONVOLUTION_1D                  glConvolutionFilter1D
       GL_CONVOLUTION_2D                  glConvolutionFilter2D
       GL_CULL_FACE                       glCullFace
       GL_DEPTH_TEST                      glDepthFunc, glDepthRange
       GL_DITHER                          glEnable
       GL_EDGE_FLAG_ARRAY                 glEdgeFlagPointer
       GL_FOG                             glFog
       GL_HISTOGRAM                       glHistogram
       GL_INDEX_ARRAY                     glIndexPointer
       GL_INDEX_LOGIC_OP                  glLogicOp
       GL_LIGHTi                          glLightModel, glLight
       GL_LIGHTING                        glMaterial, glLightModel, glLight
       GL_LINE_SMOOTH                     glLineWidth
       GL_LINE_STIPPLE                    glLineStipple
       GL_MAP1_COLOR_4                    glMap1
       GL_MAP1_INDEX                      glMap1
       GL_MAP1_NORMAL                     glMap1
       GL_MAP1_TEXTURE_COORD_1            glMap1
       GL_MAP1_TEXTURE_COORD_2            glMap1
       GL_MAP1_TEXTURE_COORD_3            glMap1
       GL_MAP1_TEXTURE_COORD_4            glMap1
       GL_MAP2_COLOR_4                    glMap2
       GL_MAP2_INDEX                      glMap2
       GL_MAP2_NORMAL                     glMap2
       GL_POLYGON_OFFSET_POINT            glPolygonOffset
       GL_POLYGON_STIPPLE                 glPolygonStipple
       GL_POST_COLOR_MATRIX_COLOR_TABLE   glColorTable
       GL_POST_CONVOLUTION_COLOR_TABLE    glColorTable
       GL_RESCALE_NORMAL                  glNormal
       GL_SCISSOR_TEST                    glScissor
       GL_SEPARABLE_2D                    glSeparableFilter2D
       GL_STENCIL_TEST                    glStencilFunc, glStencilOp
       GL_TEXTURE_1D                      glTexImage1D
       GL_TEXTURE_2D                      glTexImage2D
       GL_TEXTURE_3D                      glTexImage3D
       GL_TEXTURE_COORD_ARRAY             glTexCoordPointer
       GL_TEXTURE_GEN_Q                   glTexGen
       GL_TEXTURE_GEN_R                   glTexGen
       GL_TEXTURE_GEN_S                   glTexGen
       GL_TEXTURE_GEN_T                   glTexGen
       GL_VERTEX_ARRAY                    glVertexPointer
       ---------------------------------------------------------------------



NOTES

       If an error is generated, glIsEnabled returns 0.

       GL_COLOR_LOGIC_OP,   GL_COLOR_ARRAY,   GL_EDGE_FLAG_ARRAY,
       GL_INDEX_ARRAY,    GL_INDEX_LOGIC_OP,     GL_NORMAL_ARRAY,
       GL_POLYGON_OFFSET_FILL,            GL_POLYGON_OFFSET_LINE,
       GL_POLYGON_OFFSET_POINT,    GL_TEXTURE_COORD_ARRAY,    and
       GL_VERTEX_ARRAY  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 when glGet is
       called with GL_EXTENSIONS.

       When  the  GL_ARB_multitexture extension is supported, the
       following parameters return the associated value  for  the
       active         texture        unit.         GL_TEXTURE_1D,
       GL_TEXTURE_BINDING_1D,                      GL_TEXTURE_2D,
       GL_TEXTURE_BINDING_2D,                      GL_TEXTURE_3D,
       GL_TEXTURE_BINDING_3D, GL_TEXTURE_GEN_S, GL_TEXTURE_GEN_T,
       GL_TEXTURE_GEN_R, GL_TEXTURE_GEN_Q, GL_TEXTURE_MATRIX, and
       GL_TEXTURE_STACK_DEPTH.  Likewise, the  following  parame-
       ters  return  the  associated  value for the active client
       texture           unit:            GL_TEXTURE_COORD_ARRAY,
       GL_TEXTURE_COORD_ARRAY_SIZE,
       GL_TEXTURE_COORD_ARRAY_STRIDE,
       GL_TEXTURE_COORD_ARRAY_TYPE.

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