IRIX Base Documentation 2002 November/SGI IRIX Base Documentation 2002 November.iso/usr/share/catman/g_man/cat3/OpenGL-ftn/fglgetfragmentlight.z/fglgetfragmentlight

Text File | 2002-10-03 | 16.3 KB | 265 lines

ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt((((3333GGGG))))        OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee        ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt((((3333GGGG))))



NNNNAAAAMMMMEEEE
     ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhttttffffvvvvSSSSGGGGIIIIXXXX,,,, ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhttttiiiivvvvSSSSGGGGIIIIXXXX - return fragment
     light source parameter values


FFFFOOOORRRRTTTTRRRRAAAANNNN SSSSPPPPEEEECCCCIIIIFFFFIIIICCCCAAAATTTTIIIIOOOONNNN
     SUBROUTINE ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhttttffffvvvvSSSSGGGGIIIIXXXX( INTEGER*4 _l_i_g_h_t,
                                           INTEGER*4 _p_n_a_m_e,
                                           CHARACTER*8 _p_a_r_a_m_s )
     SUBROUTINE ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhttttiiiivvvvSSSSGGGGIIIIXXXX( INTEGER*4 _l_i_g_h_t,
                                           INTEGER*4 _p_n_a_m_e,
                                           CHARACTER*8 _p_a_r_a_m_s )


PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRRSSSS
     _l_i_g_h_t   Specifies a fragment light source.  The number of possible
             fragment lights depends on the implementation.  They are
             identified by symbolic names of the form GGGGLLLL____FFFFRRRRAAAAGGGGMMMMEEEENNNNTTTT____LLLLIIIIGGGGHHHHTTTTi____SSSSGGGGIIIIXXXX
             where 0 _< i < GGGGLLLL____MMMMAAAAXXXX____FFFFRRRRAAAAGGGGMMMMEEEENNNNTTTT____LLLLIIIIGGGGHHHHTTTTSSSS____SSSSGGGGIIIIXXXX.

     _p_n_a_m_e   Specifies a fragment light source parameter for _l_i_g_h_t.  Accepted
             symbolic names are GGGGLLLL____AAAAMMMMBBBBIIIIEEEENNNNTTTT, GGGGLLLL____DDDDIIIIFFFFFFFFUUUUSSSSEEEE, GGGGLLLL____SSSSPPPPEEEECCCCUUUULLLLAAAARRRR,
             GGGGLLLL____PPPPOOOOSSSSIIIITTTTIIIIOOOONNNN, GGGGLLLL____SSSSPPPPOOOOTTTT____DDDDIIIIRRRREEEECCCCTTTTIIIIOOOONNNN, GGGGLLLL____SSSSPPPPOOOOTTTT____EEEEXXXXPPPPOOOONNNNEEEENNNNTTTT, GGGGLLLL____SSSSPPPPOOOOTTTT____CCCCUUUUTTTTOOOOFFFFFFFF,
             GGGGLLLL____CCCCOOOONNNNSSSSTTTTAAAANNNNTTTT____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN, GGGGLLLL____LLLLIIIINNNNEEEEAAAARRRR____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN, and
             GGGGLLLL____QQQQUUUUAAAADDDDRRRRAAAATTTTIIIICCCC____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN.

     _p_a_r_a_m_s  Returns the requested data.

DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
     ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt returns in _p_a_r_a_m_s the value or values of a fragment
     light source parameter.  _l_i_g_h_t names the fragment light and is a symbolic
     name of the form GGGGLLLL____FFFFRRRRAAAAGGGGMMMMEEEENNNNTTTT____LLLLIIIIGGGGHHHHTTTTi____SSSSGGGGIIIIXXXX for 0 _< i <
     GGGGLLLL____MMMMAAAAXXXX____FFFFRRRRAAAAGGGGMMMMEEEENNNNTTTT____LLLLIIIIGGGGHHHHTTTTSSSS____SSSSGGGGIIIIXXXX, where GGGGLLLL____MMMMAAAAXXXX____FFFFRRRRAAAAGGGGMMMMEEEENNNNTTTT____LLLLIIIIGGGGHHHHTTTTSSSS____SSSSGGGGIIIIXXXX is an
     implementation dependent constant.  _p_n_a_m_e specifies one of ten fragment
     light source parameters, again by symbolic name.

     The following parameters are defined:

     GGGGLLLL____AAAAMMMMBBBBIIIIEEEENNNNTTTT          _p_a_r_a_m_s returns four integer or floating-point values
                         representing the ambient intensity of the fragment
                         light source.  Integer values, when requested, are
                         linearly mapped from the internal floating-point
                         representation such that 1.0 maps to the most
                         positive representable integer value, and -1.0 maps
                         to the most negative representable integer value.  If
                         the internal value is outside the range [-1, 1], the
                         corresponding integer return value is undefined. The
                         initial value is (0, 0, 0, 1).

     GGGGLLLL____DDDDIIIIFFFFFFFFUUUUSSSSEEEE          _p_a_r_a_m_s returns four integer or floating-point values
                         representing the diffuse intensity of the fragment
                         light source.  Integer values, when requested, are



                                                                        PPPPaaaaggggeeee 1111






ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt((((3333GGGG))))        OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee        ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt((((3333GGGG))))



                         linearly mapped from the internal floating-point
                         representation such that 1.0 maps to the most
                         positive representable integer value, and -1.0 maps
                         to the most negative representable integer value.  If
                         the internal value is outside the range [-1, 1], the
                         corresponding integer return value is undefined. The
                         initial value for GGGGLLLL____FFFFRRRRAAAAGGGGMMMMEEEENNNNTTTT____LLLLIIIIGGGGHHHHTTTT0000____SSSSGGGGIIIIXXXX is (1, 1,
                         1, 1); for other fragment lights, the initial value
                         is (0, 0, 0, 0).

     GGGGLLLL____SSSSPPPPEEEECCCCUUUULLLLAAAARRRR         _p_a_r_a_m_s returns four integer or floating-point values
                         representing the specular intensity of the fragment
                         light source.  Integer values, when requested, are
                         linearly mapped from the internal floating-point
                         representation such that 1.0 maps to the most
                         positive representable integer value, and -1.0 maps
                         to the most negative representable integer value.  If
                         the internal value is outside the range [-1, 1], the
                         corresponding integer return value is undefined. The
                         initial value for GGGGLLLL____FFFFRRRRAAAAGGGGMMMMEEEENNNNTTTT____LLLLIIIIGGGGHHHHTTTT0000____SSSSGGGGIIIIXXXX is (1, 1,
                         1, 1); for other fragment lights, the initial value
                         is (0, 0, 0, 0).

     GGGGLLLL____PPPPOOOOSSSSIIIITTTTIIIIOOOONNNN         _p_a_r_a_m_s returns four integer or floating-point values
                         representing the position of the fragment light
                         source.  Integer values, when requested, are computed
                         by rounding the internal floating-point values to the
                         nearest integer value.  The returned values are those
                         maintained in eye coordinates.  They will not be
                         equal to the values specified using ffffggggllllFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt,
                         unless the modelview matrix was identity at the time
                         ffffggggllllFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt was called. The initial value is (0,
                         0, 1, 0).

     GGGGLLLL____SSSSPPPPOOOOTTTT____DDDDIIIIRRRREEEECCCCTTTTIIIIOOOONNNN   _p_a_r_a_m_s returns three integer or floating-point values
                         representing the direction of the fragment light
                         source.  Integer values, when requested, are computed
                         by rounding the internal floating-point values to the
                         nearest integer value.  The returned values are those
                         maintained in eye coordinates.  They will not be
                         equal to the values specified using ffffggggllllFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt,
                         unless the modelview matrix was identity at the time
                         ffffggggllllFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt was called.  Although spot direction
                         is normalized before being used in the fragment
                         lighting equation, the returned values are the
                         transformed versions of the specified values prior to
                         normalization. The initial value is (0, 0, -1).

     GGGGLLLL____SSSSPPPPOOOOTTTT____EEEEXXXXPPPPOOOONNNNEEEENNNNTTTT    _p_a_r_a_m_s returns a single integer or floating-point
                         value representing the spot exponent of the fragment
                         light.  An integer value, when requested, is computed
                         by rounding the internal floating-point



                                                                        PPPPaaaaggggeeee 2222






ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt((((3333GGGG))))        OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee        ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt((((3333GGGG))))



                         representation to the nearest integer. The initial
                         value is 0.

     GGGGLLLL____SSSSPPPPOOOOTTTT____CCCCUUUUTTTTOOOOFFFFFFFF      _p_a_r_a_m_s returns a single integer or floating-point
                         value representing the spot cutoff angle of the
                         fragment light.  An integer value, when requested, is
                         computed by rounding the internal floating-point
                         representation to the nearest integer. The initial
                         value is 180.

     GGGGLLLL____CCCCOOOONNNNSSSSTTTTAAAANNNNTTTT____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN
                         _p_a_r_a_m_s returns a single integer or floating-point
                         value representing the constant (not distance-
                         related) attenuation of the fragment light.  An
                         integer value, when requested, is computed by
                         rounding the internal floating-point representation
                         to the nearest integer. The initial value is 1.

     GGGGLLLL____LLLLIIIINNNNEEEEAAAARRRR____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN
                         _p_a_r_a_m_s returns a single integer or floating-point
                         value representing the linear attenuation of the
                         fragment light.  An integer value, when requested, is
                         computed by rounding the internal floating-point
                         representation to the nearest integer. The initial
                         value is 0.

     GGGGLLLL____QQQQUUUUAAAADDDDRRRRAAAATTTTIIIICCCC____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN
                         _p_a_r_a_m_s returns a single integer or floating-point
                         value representing the quadratic attenuation of the
                         fragment light.  An integer value, when requested, is
                         computed by rounding the internal floating-point
                         representation to the nearest integer. The initial
                         value is 0.

NNNNOOOOTTTTEEEESSSS
     It is always the case that GGGGLLLL____FFFFRRRRAAAAGGGGMMMMEEEENNNNTTTT____LLLLIIIIGGGGHHHHTTTTi____SSSSGGGGIIIIXXXX =
     GGGGLLLL____FFFFRRRRAAAAGGGGMMMMEEEENNNNTTTT____LLLLIIIIGGGGHHHHTTTT0000____SSSSGGGGIIIIXXXX + i.

     If an error is generated, no change is made to the contents of _p_a_r_a_m_s.

EEEERRRRRRRROOOORRRRSSSS
     GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____EEEENNNNUUUUMMMM is generated if _l_i_g_h_t or _p_n_a_m_e is not an accepted value.

     GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____OOOOPPPPEEEERRRRAAAATTTTIIIIOOOONNNN is generated if ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt is executed
     between the execution of ffffggggllllBBBBeeeeggggiiiinnnn and the corresponding execution of
     ffffggggllllEEEEnnnndddd.


MMMMAAAACCCCHHHHIIIINNNNEEEE DDDDEEEEPPPPEEEENNNNDDDDEEEENNNNCCCCIIIIEEEESSSS
     The SSSSGGGGIIIIXXXX____ffffrrrraaaaggggmmmmeeeennnntttt____lllliiiigggghhhhttttiiiinnnngggg extension is supported only on Octane2 VPro
     systems.




                                                                        PPPPaaaaggggeeee 3333






ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt((((3333GGGG))))        OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee        ffffggggllllGGGGeeeettttFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt((((3333GGGG))))



SSSSEEEEEEEE AAAALLLLSSSSOOOO
     ffffggggllllFFFFrrrraaaaggggmmmmeeeennnnttttLLLLiiiigggghhhhtttt





















































                                                                        PPPPaaaaggggeeee 4444