NAME

glMinmax - define minmax table

C SPECIFICATION

void ggllMMiinnmmaaxx( GLenum _t_a_r_g_e_t,
               GLenum _i_n_t_e_r_n_a_l_f_o_r_m_a_t,
               GLboolean _s_i_n_k )

PARAMETERS

_t_a_r_g_e_t
The minmax table whose parameters are to be set. Must be GGLL__MMIINNMMAAXX.
_i_n_t_e_r_n_a_l_f_o_r_m_a_t
The of entries in the minmax table. Must be one of GGLL__AALLPPHHAA, GGLL__AALLPPHHAA44, GGLL__AALLPPHHAA88, GGLL__AALLPPHHAA1122, GGLL__AALLPPHHAA1166, GGLL__LLUUMMIINNAANNCCEE, GGLL__LLUUMMIINNAANNCCEE44, GGLL__LLUUMMIINNAANNCCEE88, GGLL__LLUUMMIINNAANNCCEE1122, GGLL__LLUUMMIINNAANNCCEE1166, GGLL__LLUUMMIINNAANNCCEE__AALLPPHHAA, GGLL__LLUUMMIINNAANNCCEE44__AALLPPHHAA44, GGLL__LLUUMMIINNAANNCCEE66__AALLPPHHAA22, GGLL__LLUUMMIINNAANNCCEE88__AALLPPHHAA88, GGLL__LLUUMMIINNAANNCCEE1122__AALLPPHHAA44, GGLL__LLUUMMIINNAANNCCEE1122__AALLPPHHAA1122, GGLL__LLUUMMIINNAANNCCEE1166__AALLPPHHAA1166, GGLL__RR33__GG33__BB22, GGLL__RRGGBB, GGLL__RRGGBB44, GGLL__RRGGBB55, GGLL__RRGGBB88, GGLL__RRGGBB1100, GGLL__RRGGBB1122, GGLL__RRGGBB1166, GGLL__RRGGBBAA, GGLL__RRGGBBAA22, GGLL__RRGGBBAA44, GGLL__RRGGBB55__AA11, GGLL__RRGGBBAA88, GGLL__RRGGBB1100__AA22, GGLL__RRGGBBAA1122, or GGLL__RRGGBBAA1166.
_s_i_n_k
If GGLL__TTRRUUEE, pixels will be consumed by the minmax process and no drawing or texture loading will take place. If GGLL__FFAALLSSEE, pixels will proceed to the final conversion process after minmax.

DESCRIPTION

When GGLL__MMIINNMMAAXX is enabled, the RGBA components of incoming pixels are compared to the minimum and maximum values for each component, which are stored in the 2-element minmax table. (The first element stores the minima, and the second element stores the maxima.) If a pixel component is greater than the corresponding component in the maximum element, then the maximum element is updated with the pixel component value. If a pixel component is less than the corresponding component in the minimum element, then the minimum element is updated with the pixel component value. (In both cases, if the internal of the minmax table includes luminance, then the R color component of incoming pixels is used for comparison.) The contents of the minmax table may be retrieved at a later time by calling ggllGGeettMMiinnmmaaxx. The minmax operation is enabled or disabled by calling ggllEEnnaabbllee or ggllDDiissaabbllee, respectively, with an argument of GGLL__MMIINNMMAAXX.

ggllMMiinnmmaaxx redefines the current minmax table to have entries of the specified by _i_n_t_e_r_n_a_l_f_o_r_m_a_t. The maximum element is initialized with the smallest possible component values, and the minimum element is initialized with the largest possible component values. The values in the previous minmax table, if any, are lost. If _s_i_n_k is GGLL__TTRRUUEE, then pixels are discarded after minmax; no further processing of the pixels takes place, and no drawing, texture loading, or pixel readback will result.

NOTES

ggllMMiinnmmaaxx is present only if GGLL__AARRBB__iimmaaggiinngg is returned when ggllGGeettSSttrriinngg is called with an argument of GGLL__EEXXTTEENNSSIIOONNSS.

ERRORS

GGLL__IINNVVAALLIIDD__EENNUUMM is generated if _t_a_r_g_e_t is not one of the allowable values.

GGLL__IINNVVAALLIIDD__EENNUUMM is generated if _i_n_t_e_r_n_a_l_f_o_r_m_a_t is not one of the allowable values.

GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if ggllMMiinnmmaaxx is executed between the execution of ggllBBeeggiinn and the corresponding execution of ggllEEnndd.

ASSOCIATED GETS

ggllGGeettMMiinnmmaaxxPPaarraammeetteerr

SEE ALSO

ggllGGeettMMiinnmmaaxx((33GG)), ggllRReesseettMMiinnmmaaxx((33GG))