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/ IRIX Base Documentation 2001 May / SGI IRIX Base Documentation 2001 May.iso / usr / share / catman / g_man / cat3 / OpenGL / glhistogram.z / glhistogram
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Text File  |  2001-04-17  |  10.1 KB  |  133 lines
  1.  
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  3.  
  4. ggggllllHHHHiiiissssttttooooggggrrrraaaammmm((((3333GGGG))))                OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee                ggggllllHHHHiiiissssttttooooggggrrrraaaammmm((((3333GGGG))))
  5.  
  6.  
  7.  
  8. NNNNAAAAMMMMEEEE
  9.      ggggllllHHHHiiiissssttttooooggggrrrraaaammmm - define histogram table
  10.  
  11.  
  12. CCCC SSSSPPPPEEEECCCCIIIIFFFFIIIICCCCAAAATTTTIIIIOOOONNNN
  13.      void ggggllllHHHHiiiissssttttooooggggrrrraaaammmm( GLenum _t_a_r_g_e_t,
  14.                        GLsizei _w_i_d_t_h,
  15.                        GLenum _i_n_t_e_r_n_a_l_f_o_r_m_a_t,
  16.                        GLboolean _s_i_n_k )
  17.  
  18.  
  19. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRRSSSS
  20.      _t_a_r_g_e_t          The histogram whose parameters are to be set.  Must be
  21.                      one of GGGGLLLL____HHHHIIIISSSSTTTTOOOOGGGGRRRRAAAAMMMM or GGGGLLLL____PPPPRRRROOOOXXXXYYYY____HHHHIIIISSSSTTTTOOOOGGGGRRRRAAAAMMMM.
  22.  
  23.      _w_i_d_t_h           The number of entries in the histogram table.  Must be a
  24.                      power of 2.
  25.  
  26.      _i_n_t_e_r_n_a_l_f_o_r_m_a_t  The format of entries in the histogram table.  Must be
  27.                      one of GGGGLLLL____AAAALLLLPPPPHHHHAAAA, GGGGLLLL____AAAALLLLPPPPHHHHAAAA4444, GGGGLLLL____AAAALLLLPPPPHHHHAAAA8888, GGGGLLLL____AAAALLLLPPPPHHHHAAAA11112222,
  28.                      GGGGLLLL____AAAALLLLPPPPHHHHAAAA11116666, GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE, GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE4444, GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE8888,
  29.                      GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE11112222, GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE11116666, GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE____AAAALLLLPPPPHHHHAAAA,
  30.                      GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE4444____AAAALLLLPPPPHHHHAAAA4444, GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE6666____AAAALLLLPPPPHHHHAAAA2222,
  31.                      GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE8888____AAAALLLLPPPPHHHHAAAA8888, GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE11112222____AAAALLLLPPPPHHHHAAAA4444,
  32.                      GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE11112222____AAAALLLLPPPPHHHHAAAA11112222, GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE11116666____AAAALLLLPPPPHHHHAAAA11116666,
  33.                      GGGGLLLL____RRRR3333____GGGG3333____BBBB2222, GGGGLLLL____RRRRGGGGBBBB, GGGGLLLL____RRRRGGGGBBBB4444, GGGGLLLL____RRRRGGGGBBBB5555, GGGGLLLL____RRRRGGGGBBBB8888, GGGGLLLL____RRRRGGGGBBBB11110000,
  34.                      GGGGLLLL____RRRRGGGGBBBB11112222, GGGGLLLL____RRRRGGGGBBBB11116666, GGGGLLLL____RRRRGGGGBBBBAAAA, GGGGLLLL____RRRRGGGGBBBBAAAA2222, GGGGLLLL____RRRRGGGGBBBBAAAA4444,
  35.                      GGGGLLLL____RRRRGGGGBBBB5555____AAAA1111, GGGGLLLL____RRRRGGGGBBBBAAAA8888, GGGGLLLL____RRRRGGGGBBBB11110000____AAAA2222, GGGGLLLL____RRRRGGGGBBBBAAAA11112222, or
  36.                      GGGGLLLL____RRRRGGGGBBBBAAAA11116666.
  37.  
  38.      _s_i_n_k            If GGGGLLLL____TTTTRRRRUUUUEEEE, pixels will be consumed by the histogramming
  39.                      process and no drawing or texture loading will take
  40.                      place.  If GGGGLLLL____FFFFAAAALLLLSSSSEEEE, pixels will proceed to the minmax
  41.                      process after histogramming.
  42.  
  43. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  44.      When GGGGLLLL____HHHHIIIISSSSTTTTOOOOGGGGRRRRAAAAMMMM is enabled, RGBA color components are converted to
  45.      histogram table indices by clamping to the range [0,1], multiplying by
  46.      the width of the histogram table, and rounding to the nearest integer.
  47.      The table entries selected by the RGBA indices are then incremented.  (If
  48.      the internal format of the histogram table includes luminance, then the
  49.      index derived from the R color component determines the luminance table
  50.      entry to be incremented.)  If a histogram table entry is incremented
  51.      beyond its maximum value, then its value becomes undefined.  (This is not
  52.      an error.)
  53.  
  54.      Histogramming is performed only for RGBA pixels (though these may be
  55.      specified originally as color indices and converted to RGBA by index
  56.      table lookup).  Histogramming is enabled with ggggllllEEEEnnnnaaaabbbblllleeee and disabled with
  57.      ggggllllDDDDiiiissssaaaabbbblllleeee.
  58.  
  59.  
  60.  
  61.  
  62.  
  63.                                                                         PPPPaaaaggggeeee 1111
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  66.  
  67.  
  68.  
  69.  
  70. ggggllllHHHHiiiissssttttooooggggrrrraaaammmm((((3333GGGG))))                OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee                ggggllllHHHHiiiissssttttooooggggrrrraaaammmm((((3333GGGG))))
  71.  
  72.  
  73.  
  74.      When _t_a_r_g_e_t is GGGGLLLL____HHHHIIIISSSSTTTTOOOOGGGGRRRRAAAAMMMM, ggggllllHHHHiiiissssttttooooggggrrrraaaammmm redefines the current histogram
  75.      table to have _w_i_d_t_h entries of the format specified by _i_n_t_e_r_n_a_l_f_o_r_m_a_t.
  76.      The entries are indexed 0 through width - 1, and all entries are
  77.      initialized to zero.  The values in the previous histogram table, if any,
  78.      are lost.  If _s_i_n_k is GGGGLLLL____TTTTRRRRUUUUEEEE, then pixels are discarded after
  79.      histogramming; no further processing of the pixels takes place, and no
  80.      drawing, texture loading, or pixel readback will result.
  81.  
  82.      When _t_a_r_g_e_t is GGGGLLLL____PPPPRRRROOOOXXXXYYYY____HHHHIIIISSSSTTTTOOOOGGGGRRRRAAAAMMMM, ggggllllHHHHiiiissssttttooooggggrrrraaaammmm computes all state
  83.      information as if the histogram table were to be redefined, but does not
  84.      actually define the new table.  If the requested histogram table is too
  85.      large to be supported, then the state information will be set to zero.
  86.      This provides a way to determine if a histogram table with the given
  87.      parameters can be supported.
  88.  
  89. NNNNOOOOTTTTEEEESSSS
  90.      ggggllllHHHHiiiissssttttooooggggrrrraaaammmm is present only if GGGGLLLL____AAAARRRRBBBB____iiiimmmmaaaaggggiiiinnnngggg is returned when
  91.      ggggllllGGGGeeeettttSSSSttttrrrriiiinnnngggg is called with an argument of GGGGLLLL____EEEEXXXXTTTTEEEENNNNSSSSIIIIOOOONNNNSSSS.
  92.  
  93. EEEERRRRRRRROOOORRRRSSSS
  94.      GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____EEEENNNNUUUUMMMM is generated if _t_a_r_g_e_t is not one of the allowable
  95.      values.
  96.  
  97.      GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____VVVVAAAALLLLUUUUEEEE is generated if _w_i_d_t_h is less than zero or is not a
  98.      power of 2.
  99.  
  100.      GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____EEEENNNNUUUUMMMM is generated if _i_n_t_e_r_n_a_l_f_o_r_m_a_t is not one of the
  101.      allowable values.
  102.  
  103.      GGGGLLLL____TTTTAAAABBBBLLLLEEEE____TTTTOOOOOOOO____LLLLAAAARRRRGGGGEEEE is generated if _t_a_r_g_e_t is GGGGLLLL____HHHHIIIISSSSTTTTOOOOGGGGRRRRAAAAMMMM and the
  104.      histogram table specified is too large for the implementation.
  105.  
  106.      GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____OOOOPPPPEEEERRRRAAAATTTTIIIIOOOONNNN is generated if ggggllllHHHHiiiissssttttooooggggrrrraaaammmm is executed between the
  107.      execution of ggggllllBBBBeeeeggggiiiinnnn and the corresponding execution of ggggllllEEEEnnnndddd.
  108.  
  109. AAAASSSSSSSSOOOOCCCCIIIIAAAATTTTEEEEDDDD GGGGEEEETTTTSSSS
  110.      ggggllllGGGGeeeettttHHHHiiiissssttttooooggggrrrraaaammmmPPPPaaaarrrraaaammmmeeeetttteeeerrrr
  111.  
  112.  
  113. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  114.      ggggllllGGGGeeeettttHHHHiiiissssttttooooggggrrrraaaammmm, ggggllllRRRReeeesssseeeettttHHHHiiiissssttttooooggggrrrraaaammmm
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  129.                                                                         PPPPaaaaggggeeee 2222
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