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Text File  |  2002-10-03  |  7.1 KB  |  133 lines
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  4. ffffggggllllFFFFooooggggFFFFuuuunnnnccccSSSSGGGGIIIISSSS((((3333GGGG))))             OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee             ffffggggllllFFFFooooggggFFFFuuuunnnnccccSSSSGGGGIIIISSSS((((3333GGGG))))
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  8. NNNNAAAAMMMMEEEE
  9.      ffffggggllllFFFFooooggggFFFFuuuunnnnccccSSSSGGGGIIIISSSS - custom fog blending function
  10.  
  11.  
  12. FFFFOOOORRRRTTTTRRRRAAAANNNN SSSSPPPPEEEECCCCIIIIFFFFIIIICCCCAAAATTTTIIIIOOOONNNN
  13.      SUBROUTINE ffffggggllllFFFFooooggggFFFFuuuunnnnccccSSSSGGGGIIIISSSS( INTEGER*4 _n,
  14.                                 CHARACTER*8 _p_o_i_n_t_s )
  15.  
  16.  
  17. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRRSSSS
  18.      _n       Specifies the number of control points in the custom fog blending
  19.              function.  The initial value is 1.
  20.  
  21.      _p_o_i_n_t_s  Specifies an array of control points.  Each control point
  22.              consists of two floating-point values.  The first is an eye-space
  23.              distance, and the second is a fog blending factor in the range
  24.              [0.0,1.0].  Blending factor 0.0 indicates full fog, and 1.0
  25.              indicates no fog.  The initial value is (0.0,1.0) (no fog).
  26.  
  27. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  28.      ffffggggllllFFFFooooggggFFFFuuuunnnnccccSSSSGGGGIIIISSSS defines the control points for the custom fog blending
  29.      function that is applied when the fog mode is GGGGLLLL____FFFFOOOOGGGG____FFFFUUUUNNNNCCCC____SSSSGGGGIIIISSSS.  See
  30.      ffffggggllllFFFFoooogggg for a discussion of the various fog modes and the operation of the
  31.      custom blending function.
  32.  
  33.      _n is the number of control points in the custom fog blending function.
  34.      It must not be larger than the value returned by ffffggggllllGGGGeeeetttt with argument
  35.      GGGGLLLL____MMMMAAAAXXXX____FFFFOOOOGGGG____FFFFUUUUNNNNCCCC____PPPPOOOOIIIINNNNTTTTSSSS____SSSSGGGGIIIISSSS.  It must be at least 1.
  36.  
  37.      _p_o_i_n_t_s is an array of pairs of floating-point values that define the
  38.      control points.  Each control point consists of an eye-space distance
  39.      from the viewpoint (always non-negative) and the corresponding fog
  40.      blending factor (in the range [0.0,1.0]).  Blending factor 0.0 results in
  41.      full fog, and 1.0 results in no fog.  The control points must be
  42.      specified in order: eye space distance must not decrease from one control
  43.      point to the next, and the fog blending factor must not increase from one
  44.      control point to the next.
  45.  
  46.      _n and _p_o_i_n_t_s completely specify the custom fog blending function,
  47.      replacing any previous specification that may have existed.
  48.  
  49. NNNNOOOOTTTTEEEESSSS
  50.      Note that since each control point is a pair of values, there are 2*_n
  51.      floating-point values in _p_o_i_n_t_s.
  52.  
  53.      ffffggggllllFFFFooooggggFFFFuuuunnnnccccSSSSGGGGIIIISSSS is part of the SSSSGGGGIIIISSSS____ffffoooogggg____ffffuuuunnnncccc extension, not part of the
  54.      core GL command set.  If GGGGLLLL____SSSSGGGGIIIISSSS____ffffoooogggg____ffffuuuunnnncccc is included in the string
  55.      returned by ffffggggllllGGGGeeeettttSSSSttttrrrriiiinnnngggg when called with argument GGGGLLLL____EEEEXXXXTTTTEEEENNNNSSSSIIIIOOOONNNNSSSS,
  56.      extension SSSSGGGGIIIISSSS____ffffoooogggg____ffffuuuunnnncccc is supported by the connection.  See ffffggggllllIIIInnnnttttrrrroooo for
  57.      more information about using extensions.
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  63.                                                                         PPPPaaaaggggeeee 1111
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  70. ffffggggllllFFFFooooggggFFFFuuuunnnnccccSSSSGGGGIIIISSSS((((3333GGGG))))             OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee             ffffggggllllFFFFooooggggFFFFuuuunnnnccccSSSSGGGGIIIISSSS((((3333GGGG))))
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  73.  
  74. EEEERRRRRRRROOOORRRRSSSS
  75.      GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____VVVVAAAALLLLUUUUEEEE is generated if _n is less than 1.
  76.  
  77.      GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____VVVVAAAALLLLUUUUEEEE is generated if any eye-space distance in _p_o_i_n_t_s is
  78.      negative, or if any blend factor in _p_o_i_n_t_s is outside the range
  79.      [0.0,1.0].
  80.  
  81.      GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____VVVVAAAALLLLUUUUEEEE is generated if the eye-space distance decreases from
  82.      one control point to the next, or if the blending factor increases from
  83.      one control point to the next.
  84.  
  85.      GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____OOOOPPPPEEEERRRRAAAATTTTIIIIOOOONNNN is generated if ffffggggllllFFFFooooggggFFFFuuuunnnnccccSSSSGGGGIIIISSSS is executed between
  86.      the execution of ffffggggllllBBBBeeeeggggiiiinnnn and the corresponding execution of ffffggggllllEEEEnnnndddd.
  87.  
  88. AAAASSSSSSSSOOOOCCCCIIIIAAAATTTTEEEEDDDD GGGGEEEETTTTSSSS
  89.      ffffggggllllGGGGeeeetttt with argument GGGGLLLL____FFFFOOOOGGGG____FFFFUUUUNNNNCCCC____SSSSGGGGIIIISSSS
  90.      ffffggggllllGGGGeeeetttt with argument GGGGLLLL____FFFFOOOOGGGG____FFFFUUUUNNNNCCCC____PPPPOOOOIIIINNNNTTTTSSSS____SSSSGGGGIIIISSSS
  91.      ffffggggllllGGGGeeeetttt with argument GGGGLLLL____MMMMAAAAXXXX____FFFFOOOOGGGG____FFFFUUUUNNNNCCCC____PPPPOOOOIIIINNNNTTTTSSSS____SSSSGGGGIIIISSSS
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  94. MMMMAAAACCCCHHHHIIIINNNNEEEE DDDDEEEEPPPPEEEENNNNDDDDEEEENNNNCCCCIIIIEEEESSSS
  95.      Fog mode GGGGLLLL____FFFFOOOOGGGG____FFFFUUUUNNNNCCCC____SSSSGGGGIIIISSSS is supported only on InfiniteReality systems.
  96.  
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  98. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  99.      ffffggggllllFFFFoooogggg
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  129.                                                                         PPPPaaaaggggeeee 2222
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