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Manual Reference Pages  - GLMINMAX (3G)

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glMinmax - define minmax table

CONTENTS

C Specification
Parameters
Description
Notes
Errors
Associated Gets
See Also

void glMinmax( GLenum target,

             GLenum internalformat,
             GLboolean sink )

target	The minmax table whose parameters are to be set. Must be  GL_MINMAX.
internalformat	The of entries in the minmax table. Must be one of  GL_ALPHA,  GL_ALPHA4,  GL_ALPHA8,  GL_ALPHA12,  GL_ALPHA16,  GL_LUMINANCE,  GL_LUMINANCE4,  GL_LUMINANCE8,  GL_LUMINANCE12,  GL_LUMINANCE16,  GL_LUMINANCE_ALPHA,  GL_LUMINANCE4_ALPHA4,  GL_LUMINANCE6_ALPHA2,  GL_LUMINANCE8_ALPHA8,  GL_LUMINANCE12_ALPHA4,  GL_LUMINANCE12_ALPHA12,  GL_LUMINANCE16_ALPHA16,  GL_R3_G3_B2,  GL_RGB,  GL_RGB4,  GL_RGB5,  GL_RGB8,  GL_RGB10,  GL_RGB12,  GL_RGB16,  GL_RGBA,  GL_RGBA2,  GL_RGBA4,  GL_RGB5_A1,  GL_RGBA8,  GL_RGB10_A2,  GL_RGBA12, or  GL_RGBA16.
sink	If  GL_TRUE, pixels will be consumed by the minmax process and no drawing or texture loading will take place. If  GL_FALSE, pixels will proceed to the final conversion process after minmax.

When  GL_MINMAX 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  glGetMinmax. The minmax operation is enabled or disabled by calling  glEnable or  glDisable, respectively, with an argument of  GL_MINMAX.

 glMinmax redefines the current minmax table to have entries of the specified by internalformat. 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 sink is  GL_TRUE, then pixels are discarded after minmax; no further processing of the pixels takes place, and no drawing, texture loading, or pixel readback will result.

 glMinmax is present only if  GL_ARB_imaging is returned when  glGetString is called with an argument of  GL_EXTENSIONS.

 GL_INVALID_ENUM is generated if target is not one of the allowable values.

 GL_INVALID_ENUM is generated if internalformat is not one of the allowable values.

 GL_INVALID_OPERATION is generated if  glMinmax is executed between the execution of  glBegin and the corresponding execution of  glEnd.

 glGetMinmaxParameter

 glGetMinmax(3G),  glResetMinmax(3G)

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