fglBlendColorEXT(3G)

NAME
     fglBlendColorEXT - set the blend color


FORTRAN SPECIFICATION
     SUBROUTINE fglBlendColorEXT( REAL*4 red,
                                  REAL*4 green,
                                  REAL*4 blue,
                                  REAL*4 alpha )


PARAMETERS
     red, green, blue, alpha specify the components of GL_BLEND_COLOR_EXT


DESCRIPTION
     The GL_BLEND_COLOR_EXT may be used to calculate the source and
     destination blending factors. See fglBlendFunc for a complete description
     of the blending operations.  Initially the GL_BLEND_COLOR_EXT is set to
     (0,0,0,0).

NOTES
     fglBlendColorEXT is part of the EXT_blend_color extension, not part of
     the core GL command set.  If GL_EXT_blend_color is included in the string
     returned by fglGetString, when called with argument GL_EXTENSIONS,
     extension EXT_blend_color is supported by the connection.

ERRORS
     GL_INVALID_OPERATION is generated if fglBlendColorEXT is executed between
     the execution of fglBegin and the corresponding execution of fglEnd.

ASSOCIATED GETS
     fglGet with an argument of GL_BLEND_COLOR_EXT.


MACHINE DEPENDENCIES
     RealityEngine, RealityEngine2, and VTX systems do not support the use of
     source blend factor GL_SRC_ALPHA_SATURATE and a destination factor based
     on the constant blend color (GL_.._CONSTANT_.._EXT); such combinations
     produce incorrect results.


SEE ALSO
     fglBlendFunc, fglGetString.