glPixelMap(3G)glPixelMap(3G)NAME
glPixelMap, glPixelMapfv, glPixelMapuiv, glPixelMapusv - set up pixel
transfer maps
SYNOPSIS
void glPixelMapfv(
GLenum map,
GLint mapsize,
const GLfloat *values ); void glPixelMapuiv(
GLenum map,
GLint mapsize,
const GLuint *values ); void glPixelMapusv(
GLenum map,
GLint mapsize,
const GLushort *values );
PARAMETERS
Specifies a symbolic map name. Must be one of the following:
GL_PIXEL_MAP_I_TO_I, GL_PIXEL_MAP_S_TO_S, GL_PIXEL_MAP_I_TO_R,
GL_PIXEL_MAP_I_TO_G, GL_PIXEL_MAP_I_TO_B, GL_PIXEL_MAP_I_TO_A,
GL_PIXEL_MAP_R_TO_R, GL_PIXEL_MAP_G_TO_G, GL_PIXEL_MAP_B_TO_B, or
GL_PIXEL_MAP_A_TO_A. Specifies the size of the map being defined.
Specifies an array of mapsize values.
DESCRIPTIONglPixelMap() sets up translation tables, or maps, used by glCopyPix‐
els(), glCopyTexImage1D(), glCopyTexImage2D(), glCopyTexSubImage1D(),
glCopyTexSubImage2D(), glCopyTexSubImage3D(), glDrawPixels(), glRead‐
Pixels(), glTexImage1D(), glTexImage2D(), glTexImage3D(), glTexSubIm‐
age1D(), glTexSubImage2D(), and glTexSubImage3D(). Additionally, if the
GL_ARB_imaging subset is supported, the routines glColorTable(), glCol‐
orSubTable(), glConvolutionFilter1D(), glConvolutionFilter2D(), glHis‐
togram(), glMinmax(), 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: Maps color indices to color indices. Maps
stencil indices to stencil indices. Maps color indices to red compo‐
nents. Maps color indices to green components. Maps color indices to
blue components. Maps color indices to alpha components. Maps red
components to red components. Maps green components to green compo‐
nents. Maps blue components to blue components. Maps alpha components
to alpha components.
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 GL_PIXEL_MAP_I_TO_I and
GL_PIXEL_MAP_S_TO_S) retain their values in floating-point , with
unspecified mantissa and exponent sizes. Floating-point values speci‐
fied by glPixelMapfv() are converted directly to the internal floating-
point of these maps, then clamped to the range [0,1]. Unsigned integer
values specified by glPixelMapusv() and glPixelMapuiv() are converted
linearly such that the largest representable integer maps to 1.0, and 0
maps to 0.0.
Maps that store indices, GL_PIXEL_MAP_I_TO_I and GL_PIXEL_MAP_S_TO_S,
retain their values in fixed-point , with an unspecified number of bits
to the right of the binary point. Floating-point values specified by
glPixelMapfv() are converted directly to the internal fixed-point of
these maps. Unsigned integer values specified by glPixelMapusv() and
glPixelMapuiv() 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 sup n for some n or the results are undefined. The
maximum allowable size for each map depends on the implementation and
can be determined by calling glGet() with argument GL_MAX_PIXEL_MAP_TA‐
BLE. The single maximum applies to all maps; it is at least 32.
───────────────────────────────────────────────────────────────────────
map Lookup Index Lookup Value Initial Ini‐
Size tial
Value
───────────────────────────────────────────────────────────────────────
GL_PIXEL_MAP_I_TO_I color index color index 1 0
GL_PIXEL_MAP_S_TO_S stencil index stencil index 1 0
GL_PIXEL_MAP_I_TO_R color index R 1 0
GL_PIXEL_MAP_I_TO_G color index G 1 0
GL_PIXEL_MAP_I_TO_B color index B 1 0
GL_PIXEL_MAP_I_TO_A color index A 1 0
GL_PIXEL_MAP_R_TO_R R R 1 0
GL_PIXEL_MAP_G_TO_G G G 1 0
GL_PIXEL_MAP_B_TO_B B B 1 0
GL_PIXEL_MAP_A_TO_A A A 1 0
───────────────────────────────────────────────────────────────────────
ERRORS
GL_INVALID_ENUM is generated if map is not an accepted value.
GL_INVALID_VALUE is generated if mapsize is less than one or larger
than GL_MAX_PIXEL_MAP_TABLE.
GL_INVALID_VALUE is generated if map is GL_PIXEL_MAP_I_TO_I,
GL_PIXEL_MAP_S_TO_S, GL_PIXEL_MAP_I_TO_R, GL_PIXEL_MAP_I_TO_G,
GL_PIXEL_MAP_I_TO_B, or GL_PIXEL_MAP_I_TO_A, and mapsize is not a power
of two.
GL_INVALID_OPERATION is generated if glPixelMap() is executed between
the execution of glBegin() and the corresponding execution of glEnd().
ASSOCIATED GETSglGetPixelMap()glGet() with argument GL_PIXEL_MAP_I_TO_I_SIZE
glGet() with argument GL_PIXEL_MAP_S_TO_S_SIZE
glGet() with argument GL_PIXEL_MAP_I_TO_R_SIZE
glGet() with argument GL_PIXEL_MAP_I_TO_G_SIZE
glGet() with argument GL_PIXEL_MAP_I_TO_B_SIZE
glGet() with argument GL_PIXEL_MAP_I_TO_A_SIZE
glGet() with argument GL_PIXEL_MAP_R_TO_R_SIZE
glGet() with argument GL_PIXEL_MAP_G_TO_G_SIZE
glGet() with argument GL_PIXEL_MAP_B_TO_B_SIZE
glGet() with argument GL_PIXEL_MAP_A_TO_A_SIZE
glGet() with argument GL_MAX_PIXEL_MAP_TABLE
SEE ALSOglColorTable(3), glColorSubTable(3), glConvolutionFilter1D(3), glConvo‐
lutionFilter2D(3), glCopyPixels(3), glCopyTexImage1D(3), glCopyTexIm‐
age2D(3), glCopyTexSubImage1D(3), glCopyTexSubImage2D(3), glDrawPix‐
els(3), glHistogram(3), glMinmax(3), glPixelStore(3), glPixelTrans‐
fer(3), glReadPixels(3), glSeparableFilter2D(3), glTexImage1D(3),
glTexImage2D(3), glTexImage3D(3), glTexSubImage1D(3), glTexSubIm‐
age2D(3), glTexSubImage3D(3)glPixelMap(3G)