glPixelMap : PyOpenGL 3.1.4 GL Man Pages

set up pixel transfer maps

Signature

glPixelMap( )->

glPixelMapfv( GLenum ( map ) , GLsizei ( mapsize ) , const GLfloat * ( values ) )-> void

glPixelMapfv( map , mapsize , values )

glPixelMapuiv( GLenum ( map ) , GLsizei ( mapsize ) , const GLuint * ( values ) )-> void

glPixelMapuiv( map , mapsize , values )

glPixelMapusv( GLenum ( map ) , GLsizei ( mapsize ) , const GLushort * ( values ) )-> void

glPixelMapusv( map , mapsize , values )

Parameters

Variables	Description
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

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.

If a non-zero named buffer object is bound to the GL_PIXEL_UNPACK_BUFFER target (see glBindBuffer ) while a pixel transfer map is specified, values is treated as a byte offset into the buffer object's data store.

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 int 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 format, with unspecified mantissa and exponent sizes. Floating-point values specified by glPixelMapfv are converted directly to the internal floating-point format 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 format, 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 format 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^{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
GL_PIXEL_MAP_I_TO_I	color index	color index	1
GL_PIXEL_MAP_S_TO_S	stencil index	stencil index	1
GL_PIXEL_MAP_I_TO_R	color index	R	1
GL_PIXEL_MAP_I_TO_G	color index	G	1
GL_PIXEL_MAP_I_TO_B	color index	B	1
GL_PIXEL_MAP_I_TO_A	color index	A	1
GL_PIXEL_MAP_R_TO_R	R	R	1
GL_PIXEL_MAP_G_TO_G	G	G	1
GL_PIXEL_MAP_B_TO_B	B	B	1
GL_PIXEL_MAP_A_TO_A	A	A	1

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 a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_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_UNPACK_BUFFER target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size.

GL_INVALID_OPERATION is generated by glPixelMapfv if a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_BUFFER target and values is not evenly divisible into the number of bytes needed to store in memory a GLfloat datum.

GL_INVALID_OPERATION is generated by glPixelMapuiv if a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_BUFFER target and values is not evenly divisible into the number of bytes needed to store in memory a GLuint datum.

GL_INVALID_OPERATION is generated by glPixelMapusv if a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_BUFFER target and values is not evenly divisible into the number of bytes needed to store in memory a GLushort datum.

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

glGet with argument GL_PIXEL_UNPACK_BUFFER_BINDING

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/ .

glPixelMap

Signature

Parameters

Description

Errors

Associated Gets

See Also

Copyright

Copyright Notices

MathML Rendering