 |
Index for
Section 3G |
|
 |
Alphabetical
listing for G |
|
 |
Bottom of
page |
|
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
map 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.
mapsize
Specifies the size of the map being defined.
values
Specifies an array of mapsize values.
DESCRIPTION
glPixelMap() 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 GL_ARB_imaging subset is supported, the routines glColorTable(),
glColorSubTable(), glConvolutionFilter1D(), glConvolutionFilter2D(),
glHistogram(), 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:
GL_PIXEL_MAP_I_TO_I
Maps color indices to color indices.
GL_PIXEL_MAP_S_TO_S
Maps stencil indices to stencil indices.
GL_PIXEL_MAP_I_TO_R
Maps color indices to red components.
GL_PIXEL_MAP_I_TO_G
Maps color indices to green components.
GL_PIXEL_MAP_I_TO_B
Maps color indices to blue components.
GL_PIXEL_MAP_I_TO_A
Maps color indices to alpha components.
GL_PIXEL_MAP_R_TO_R
Maps red components to red components.
GL_PIXEL_MAP_G_TO_G
Maps green components to green components.
GL_PIXEL_MAP_B_TO_B
Maps blue components to blue components.
GL_PIXEL_MAP_A_TO_A
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 specified 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_TABLE. The
single maximum applies to all maps; it is at least 32.
_______________________________________________________________________
map Lookup Index Lookup Value
Initial
Size
Initial
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 GETS
glGetPixelMap()
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 ALSO
glColorTable(3), glColorSubTable(3), glConvolutionFilter1D(3),
glConvolutionFilter2D(3), glCopyPixels(3), glCopyTexImage1D(3),
glCopyTexImage2D(3), glCopyTexSubImage1D(3), glCopyTexSubImage2D(3),
glDrawPixels(3), glHistogram(3), glMinmax(3), glPixelStore(3),
glPixelTransfer(3), glReadPixels(3), glSeparableFilter2D(3),
glTexImage1D(3), glTexImage2D(3), glTexImage3D(3), glTexSubImage1D(3),
glTexSubImage2D(3), glTexSubImage3D(3)
|
Index for
Section 3G |
|
|
Alphabetical
listing for G |
|
 |
Top of
page |
|