HP b2600 Reference Manual page 141

is produced, and if any of GL_MAP1_TEXTURE_COORD_1,
GL_MAP1_TEXTURE_COORD_2, GL_MAP1_TEXTURE_COORD_3,
GL_MAP1_TEXTURE_COORD_4, GL_MAP2_TEXTURE_COORD_1,
GL_MAP2_TEXTURE_COORD_2, GL_MAP2_TEXTURE_COORD_3, or
GL_MAP2_TEXTURE_COORD_4 is enabled, then an appropriate glTexCoord command
is simulated.
For color, color index, normal, and texture coordinates the GL uses evaluated values
instead of current values for those evaluations that are enabled, and current values
otherwise, However, the evaluated values do not update the current values. Thus, if
glVertex commands are interspersed with glEvalCoord commands, the color, normal, and
texture coordinates associated with the glVertex commands are not affected by the
values generated by the glEvalCoord commands, but only by the most recent glColor,
glIndex, glNormal, and glTexCoord commands.
No commands are issued for maps that are not enabled. If more than one texture
evaluation is enabled for a particular dimension (for example,
GL_MAP2_TEXTURE_COORD_1 and GL_MAP2_TEXTURE_COORD_2), then only the
evaluation of the map that produces the larger number of coordinates (in this case,
GL_MAP2_TEXTURE_COORD_2) is carried out. GL_MAP1_VERTEX_4 overrides
GL_MAP1_VERTEX_3, and GL_MAP2_VERTEX_4 overrides GL_MAP2_VERTEX_3, in
the same manner. If neither a three- nor a four-component vertex map is enabled for the
specified dimension, the glEvalCoord command is ignored.
If you have enabled automatic normal generation, by calling glEnable with argument
GL_AUTO_NORMAL, glEvalCoord2 generates surface normals analytically, regardless
of the contents or enabling of the GL_MAP2_NORMAL map. Let
m
Then the generated normal n is
n
If automatic normal generation is disabled, the corresponding normal map
GL_MAP2_NORMAL, if enabled, is used to produce a normal. If neither automatic
normal generation nor a normal map is enabled, no normal is generated for
glEvalCoord2 commands.
Associated Gets
glIsEnabled with argument GL_MAP1_VERTEX_3
glIsEnabled with argument GL_MAP1_VERTEX_4
glIsEnabled with argument GL_MAP1_INDEX
glIsEnabled with argument GL_MAP1_COLOR_4
glIsEnabled with argument GL_MAP1_NORMAL
glIsEnabled with argument GL_MAP1_TEXTURE_COORD_1
glIsEnabled with argument GL_MAP1_TEXTURE_COORD_2
glIsEnabled with argument GL_MAP1_TEXTURE_COORD_3
glIsEnabled with argument GL_MAP1_TEXTURE_COORD_4
glIsEnabled with argument GL_MAP2_VERTEX_3
glIsEnabled with argument GL_MAP2_VERTEX_4
Chapter 5
p p
----- - ----- -
=
u v
m
----------
=
m
E
glEvalCoord
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