glGetMinmax(3G) OpenGL Reference glGetMinmax(3G)
glGetMinmax - get minimum and maximum pixel values
void glGetMinmax( GLenum target,
GLboolean reset,
GLenum format,
GLenum type,
GLvoid *values )
target Must be GL_MINMAX.
reset If GL_TRUE, all entries in the minmax table that are actually
returned are reset to their initial values. (Other entries are
unaltered.) If GL_FALSE, the minmax table is unaltered.
format The format of the data to be returned in values. Must be one of
GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_RGB, GL_BGR, GL_RGBA,
GL_BGRA, GL_ABGR_EXT, GL_LUMINANCE, or GL_LUMINANCE_ALPHA.
type The type of the data to be returned in values. Symbolic
constants GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP,
GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT, GL_INT, GL_FLOAT,
GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_5_6_5_REV,
GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV,
GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, and GL_UNSIGNED_INT_2_10_10_10_REV
are accepted.
values A pointer to storage for the returned values.
glGetMinmax returns the accumulated minimum and maximum pixel values
(computed on a per-component basis) in a one-dimensional image of width
2. The first set of return values are the minima, and the second set of
return values are the maxima. The format of the return values is
determined by format, and their type is determined by type.
No pixel transfer operations are performed on the return values, but
pixel storage modes that are applicable to 1-dimensional images are
performed. Color components that are requested in the specified format,
but that are not included in the internal format of the minmax table, are
returned as zero. The assignment of internal color components to the
components requested by format are as follows:
________________________________________
Internal Component Resulting Component
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glGetMinmax(3G) OpenGL Reference glGetMinmax(3G)
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Red Red
Green Green
Blue Blue
Alpha Alpha
Luminance Red
________________________________________
If reset is GL_TRUE, the minmax table entries corresponding to the return
values are reset to their initial values. Minimum and maximum values
that are not returned are not modified, even if reset is GL_TRUE.
glGetMinmax is present only if GL_ARB_imaging is returned when
glGetString is called with an argument of GL_EXTENSIONS.
GL_ABGR_EXT is valid only if the EXT_abgr extension is supported.
GL_INVALID_ENUM is generated if target is not GL_MINMAX.
GL_INVALID_ENUM is generated if format is not one of the allowable
values.
GL_INVALID_ENUM is generated if type is not one of the allowable values.
GL_INVALID_OPERATION is generated if glGetMinmax is executed between the
execution of glBegin and the corresponding execution of glEnd.
GL_INVALID_OPERATION is generated if type is one of
GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5, or GL_UNSIGNED_SHORT_5_6_5_REV and format is not
GL_RGB.
GL_INVALID_OPERATION is generated if type is one of
GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV,
GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, or GL_UNSIGNED_INT_2_10_10_10_REV and format
is not GL_RGBA, GL_BGRA or GL_ABGR_EXT.
glMinmax, glResetMinmax, glGetMinmaxParameter
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