Signature
Parameters
Variables | Description |
---|---|
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_LUMINANCE
, or
GL_LUMINANCE_ALPHA
.
|
types |
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.
|
Description
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 |
Notes
glGetMinmax
is present only if
ARB_imaging
is returned when
glGetString
is called with an argument of
GL_EXTENSIONS
.
Errors
GL_INVALID_ENUM
is generated if
format
is not one of the allowable
values.
GL_INVALID_ENUM
is generated if
types
is not one of the allowable
values.
GL_INVALID_OPERATION
is generated if
types
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
types
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 neither
GL_RGBA
nor
GL_BGRA
.
GL_INVALID_OPERATION
is generated if a non-zero buffer object name is bound to the
GL_PIXEL_PACK_BUFFER
target and the buffer object's data store is currently mapped.
GL_INVALID_OPERATION
is generated if a non-zero buffer object name is bound to the
GL_PIXEL_PACK_BUFFER
target and the data would be packed to the buffer
object such that the memory writes required would exceed the data store size.
GL_INVALID_OPERATION
is generated if a non-zero buffer object name is bound to the
GL_PIXEL_PACK_BUFFER
target and
values
is not evenly divisible
into the number of bytes needed to store in memory a datum indicated by
type
.
GL_INVALID_OPERATION
is generated if
glGetMinmax
is executed
between the execution of
glBegin
and the corresponding
execution of
glEnd
.
Associated Gets
glGet
with argument
GL_PIXEL_PACK_BUFFER_BINDING
See Also
Copyright
Copyright
1991-2006
Silicon Graphics, Inc. This document is licensed under the SGI
Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/
.