GLPIXELMAP(3G) GLPIXELMAP(3G)
NAME
glPixelapfv,, glPixelapuiv,, glPixelapusv - set up pixel transfer maps
C SPECIFICATION
void glPixelapfv( GLenum map,
GLint mapsize,
const GLfloat *values )
void glPixelapuiv( GLenum map,
GLint mapsize,
const GLuint *values )
void glPixelapusv( GLenum map,
GLint mapsize,
const GLushort *values )
PARAMETERS
map Specifies a symbolic map name. Must be one of the following:
GLPIXELMAPITOI, GLPIXELMAPSTOS, GLPIXELMAPITOR,
GLPIXELMAPITOG, GLPIXELMAPITOB, GLPIXELMAPITOA,
GLPIXELMAPRTOR, GLPIXELMAPGTOG, GLPIXELMAPBTOB,
or GLPIXELMAPATOA.
mapsize Specifies the size of the map being defined.
values Specifies an array of mapsize values.
DESCRIPTION
glPixelap sets up translation tables, or maps, used by glCopyPixels,
glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D,
glCopyTexSubImage2D, glCopyTexSubImage3D, glDrawPixels, glReadPixels,
glTexImage1D, glTexImage2D, glTexImage3D, glTexSubImage1D,
glTexSubImage2D, and glTexSubImage3D. Additionally, if the
GLARBimaging subset is supported, the routines glColorTable,
glColorSubTable, glConvolutionFilter1D, glConvolutionFilter2D,
glHistogram, glinmax, and glSeparableFilter2D. Use of these maps is
described completely in the glPixelTransfer reference page, and partly
in the reference pages for the pixel and texture image commands. Only
the specification of the maps is described in this reference page.
map is a symbolic map name, indicating one of ten maps to set. mapsize
specifies the number of entries in the map, and values is a pointer to
an array of mapsize map values.
The ten maps are as follows:
GLPIXELMAPITOI Maps color indices to color indices.
GLPIXELMAPSTOS Maps stencil indices to stencil indices.
GLPIXELMAPITOR Maps color indices to red components.
GLPIXELMAPITOG Maps color indices to green components.
GLPIXELMAPITOB Maps color indices to blue components.
GLPIXELMAPITOA Maps color indices to alpha components.
GLPIXELMAPRTOR Maps red components to red components.
GLPIXELMAPGTOG Maps green components to green compo-
nents.
GLPIXELMAPBTOB Maps blue components to blue components.
GLPIXELMAPATOA Maps alpha components to alpha compo-
nents.
The entries in a map can be specified as single-precision floating-
point numbers, unsigned short integers, or unsigned long integers.
Maps that store color component values (all but GLPIXELMAPITOI and
GLPIXELMAPSTOS) retain their values in floating-point , with
unspecified mantissa and exponent sizes. Floating-point values speci-
fied by glPixelapfv are converted directly to the internal floating-
point of these maps, then clamped to the range [0,1]. Unsigned inte-
ger values specified by glPixelapusv and glPixelapuiv are converted
linearly such that the largest representable integer maps to 1.0, and 0
maps to 0.0.
Maps that store indices, GLPIXELMAPITOI and GLPIXELMAPSTOS,
retain their values in fixed-point , with an unspecified number of bits
to the right of the binary point. Floating-point values specified by
glPixelapfv are converted directly to the internal fixed-point of
these maps. Unsigned integer values specified by glPixelapusv and
glPixelapuiv specify integer values, with all 0's to the right of the
binary point.
The following table shows the initial sizes and values for each of the
maps. Maps that are indexed by either color or stencil indices must
have mapsize = 2^n for some n or the results are undefined. The maxi-
mum allowable size for each map depends on the implementation and can
be determined by calling glGet with argument GLMAXPIXELMAPTABLE.
The single maximum applies to all maps; it is at least 32.
map Lookup Lookup Initial Initial
Index Value Size Value
GLPIXELMAPITOI color color 1 0
index index
GLPIXELMAPSTOS stencil stencil 1 0
index index
GLPIXELMAPITOR color R 1 0
index
GLPIXELMAPITOG color G 1 0
index
GLPIXELMAPITOB color B 1 0
index
GLPIXELMAPITOA color A 1 0
index
GLPIXELMAPRTOR R R 1 0
GLPIXELMAPGTOG G G 1 0
GLPIXELMAPBTOB B B 1 0
GLPIXELMAPATOA A A 1 0
ERORS
GLINVALIDENUM is generated if map is not an accepted value.
GLINVALIDVALUE is generated if mapsize is less than one or larger
than GLMAXPIXELMAPTABLE.
GLINVALIDVALUE is generated if map is GLPIXELMAPITOI,
GLPIXELMAPSTOS, GLPIXELMAPITOR, GLPIXELMAPITOG,
GLPIXELMAPITOB, or GLPIXELMAPITOA, and mapsize is not a power
of two.
GLINVALIDOPERATION is generated if glPixelap is executed between the
execution of glBegin and the corresponding execution of glEnd.
ASOCIATED GETS
glGetPixelap
glGet with argument GLPIXELMAPITOISIZE
glGet with argument GLPIXELMAPSTOSIZE
glGet with argument GLPIXELMAPITORSIZE
glGet with argument GLPIXELMAPITOGSIZE
glGet with argument GLPIXELMAPITOBSIZE
glGet with argument GLPIXELMAPITOASIZE
glGet with argument GLPIXELMAPRTORSIZE
glGet with argument GLPIXELMAPGTOGSIZE
glGet with argument GLPIXELMAPBTOBSIZE
glGet with argument GLPIXELMAPATOASIZE
glGet with argument GLMAXPIXELMAPTABLE
SEE ALSO
glColorTable, glColorSubTable, glConvolutionFilter1D,
glConvolutionFilter2D, glCopyPixels, glCopyTexImage1D,
glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D,
glDrawPixels, glHistogram, glinmax, glPixelStore, glPixelTransfer,
glReadPixels, glSeparableFilter2D, glTexImage1D, glTexImage2D,
glTexImage3D, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D
GLPIXELMAP(3G)
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