void GLAPIENTRY glLightModelf( GLenum pname,
                                      GLfloat param )
       void GLAPIENTRY glLightModeli( GLenum pname,
                                      GLint param )

PARAMETERS
       pname   Specifies   a   single-valued    lighting    model    parameter.
               GL_LIGHT_MODEL_LOCAL_VIEWER,  GL_LIGHT_MODEL_COLOR_CONTROL,  and
               GL_LIGHT_MODEL_TWO_SIDE are accepted.

       param   Specifies the value that param will be set to.

C SPECIFICATION
       void GLAPIENTRY glLightModelfv( GLenum pname,
                                       const GLfloat *params )
       void GLAPIENTRY glLightModeliv( GLenum pname,
                                       const GLint *params )

PARAMETERS
       pname  Specifies a lighting  model  parameter.   GL_LIGHT_MODEL_AMBIENT,
              GL_LIGHT_MODEL_COLOR_CONTROL,   GL_LIGHT_MODEL_LOCAL_VIEWER,  and
              GL_LIGHT_MODEL_TWO_SIDE are accepted.

       params Specifies a pointer to the value or values that  params  will  be
              set to.

DESCRIPTION
       glLightModel sets the lighting model parameter.  pname names a parameter
       and params gives the new value.  There are three lighting model  parame‐
       ters:

       GL_LIGHT_MODEL_AMBIENT
                 params  contains  four  integer  or floating-point values that
                 specify the ambient RGBA intensity of the entire scene.  Inte‐
                 ger  values  are  mapped  linearly such that the most positive
                 representable value maps to 1.0, and the most negative  repre‐
                 sentable value maps to -1.0.  Floating-point values are mapped
                 directly.   Neither  integer  nor  floating-point  values  are
                 clamped.   The  initial  ambient scene intensity is (0.2, 0.2,
                 0.2, 1.0).

       GL_LIGHT_MODEL_COLOR_CONTROL
                 params   must   be   either   GL_SEPARATE_SPECULAR_COLOR    or
                 GL_SINGLE_COLOR.   GL_SINGLE_COLOR  specifies  that  a  single
                 color is generated from the lighting computation for a vertex.
                 GL_SEPARATE_SPECULAR_COLOR  specifies  that the specular color
                 computation of lighting be stored separately from the  remain‐
                 der of the lighting computation.  The specular color is summed
                 into the generated fragment's color after the  application  of
                 texture   mapping   (if   enabled).    The  initial  value  is
                 GL_SINGLE_COLOR.

                 sided lighting is specified, and only the front  material  pa‐
                 rameters  are  used in the lighting equation.  Otherwise, two-
                 sided lighting is specified.  In this case, vertices of  back-
                 facing  polygons  are  lighted using the back material parame‐
                 ters, and have their  normals  reversed  before  the  lighting
                 equation  is evaluated.  Vertices of front-facing polygons are
                 always lighted using the front material  parameters,  with  no
                 change to their normals. The initial value is 0.

       In  RGBA  mode, the lighted color of a vertex is the sum of the material
       emission intensity, the product of the material ambient reflectance  and
       the lighting model full-scene ambient intensity, and the contribution of
       each enabled light source.  Each light source  contributes  the  sum  of
       three  terms:  ambient, diffuse, and specular.  The ambient light source
       contribution is the product of the material ambient reflectance and  the
       light's ambient intensity.  The diffuse light source contribution is the
       product of the material diffuse reflectance, the light's diffuse  inten‐
       sity,  and  the  dot  product of the vertex's normal with the normalized
       vector from the vertex to the light source.  The specular  light  source
       contribution  is  the  product of the material specular reflectance, the
       light's specular intensity, and the dot product of the  normalized  ver‐
       tex-to-eye  and  vertex-to-light  vectors,  raised  to  the power of the
       shininess of the material.  All three light source contributions are at‐
       tenuated  equally  based  on  the  distance from the vertex to the light
       source and on light source direction, spread exponent, and spread cutoff
       angle.  All dot products are replaced with 0 if they evaluate to a nega‐
       tive value.

       The alpha component of the resulting lighted color is set to  the  alpha
       value of the material diffuse reflectance.

       In  color  index mode, the value of the lighted index of a vertex ranges
       from the ambient to the  specular  values  passed  to  glMaterial  using
       GL_COLOR_INDEXES.   Diffuse  and  specular coefficients, computed with a
       (.30, .59, .11) weighting of the lights' colors, the  shininess  of  the
       material,  and  the  same reflection and attenuation equations as in the
       RGBA case, determine how much above ambient the resulting index is.

NOTES
       GL_LIGHT_MODEL_COLOR_CONTROL is available only if the GL version is  1.2
       or greater.

ERRORS
       GL_INVALID_ENUM is generated if pname is not an accepted value.

       GL_INVALID_ENUM  is  generated  if pname is GL_LIGHT_MODEL_COLOR_CONTROL
       and params is not one of GL_SINGLE_COLOR or GL_SEPARATE_SPECULAR_COLOR.

       GL_INVALID_OPERATION is generated if glLightModel  is  executed  between
       the execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS