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 types. If a non-zero named buffer object is bound to the GL_PIXEL_PACK_BUFFER target (see glBindBuffer ) while minimum and maximum pixel values are requested, values is treated as a byte offset into the buffer object's data store. No pixel transfer operations are performed on the return values, but pixel storage modes that are applicable to one-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 ComponentResulting Component 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 ARB_imaging is returned when glGetString is called with an argument of GL_EXTENSIONS.
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glGetMinmax: man2/glGetMinmax.xml
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 types. If a non-zero named buffer object is bound to the GL_PIXEL_PACK_BUFFER target (see glBindBuffer ) while minimum and maximum pixel values are requested, values is treated as a byte offset into the buffer object's data store. No pixel transfer operations are performed on the return values, but pixel storage modes that are applicable to one-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 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 ARB_imaging is returned when glGetString is called with an argument of GL_EXTENSIONS.