GLGETCOLORTABLESGI(3gl)GLGETCOLORTABLESGI(3gl)NAME
glGetColorTableSGI - retrieve contents of a color lookup table
C SPECIFICATION
void glGetColorTableSGI( GLenum target,
GLenum format,
GLenum type,
GLvoid* ctable )
PARAMETERS
target Must be GL_TEXTURE_COLOR_TABLE_SGI or GL_COLOR_TABLE_SGI.
format The format of the pixel data in ctable. The possible values
are GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_LUMINANCE, GL_LUMI‐
NANCE_ALPHA, GL_RGB, GL_RGBA, and GL_ABGR_EXT.
type The type of the pixel data in ctable. The allowable values are
GL_UNSIGNED_BYTE, GL_BYTE, GL_UNSIGNED_SHORT, GL_SHORT,
GL_UNSIGNED_INT, GL_INT, GL_FLOAT.
ctable Pointer to a one-dimensional array of pixel data containing the
contents of the color table.
DESCRIPTION
glGetColorTableSGI is part of the GL_SGI_color_table extension, and is
also used by the GL_SGI_texture_color_table extension.
glGetColorTableSGI returns in ctable the contents of the color table
specified by target. No pixel transfer operations are performed, but
pixel storage modes that are applicable to glReadPixels are performed.
Color components that are requested in the specified format, but which
are not included in the internal format of the color lookup table, are
returned as zero. The assignments of internal color components to the
components requested by format are:
┌─────────────────────────────────────────┐
│Internal Component Resulting Component │
├─────────────────────────────────────────┤
│ red red │
│ green green │
│ blue blue │
│ alpha alpha │
│ luminance red │
│ intensity red │
└─────────────────────────────────────────┘
NOTES
If target is set to GL_TEXTURE_COLOR_TABLE_SGI and the GL_SGI_tex‐
ture_color_table extension is not supported, then a GL_INVALID_ENUM
error is generated.
If target is set to GL_COLOR_TABLE_SGI and the GL_SGI_color_table
extension is not supported then an GL_INVALID_ENUM error is generated.
ERRORS
GL_INVALID_ENUM is generated if target is not one of the allowable val‐
ues.
GL_INVALID_ENUM is generated if format is not one of the allowable val‐
ues.
GL_INVALID_ENUM is generated if type is not one of the allowable val‐
ues.
GL_INVALID_OPERATION is generated if glGetColorTableSGI is executed
between the execution of glBegin and the corresponding execution of
glEnd.
SEE ALSO
glColorTableSGI, glColorTableParameterSGI, glGetColorTableParameterSGI
15 Mar 97 GLGETCOLORTABLESGI(3gl)