Linux and UNIX Man Pages

Test Your Knowledge in Computers #592
Difficulty: Medium
Suppose we want to sort a huge collection of 1 trillion, 10^12, elements. Doing so with Selection Sort or Insertion Sort would require about n^2 = (10^12)^2 = 10^24 or 1 sextillion comparisons.
True or False?

glevalcoord2d(3g) [xfree86 man page]

```GLEVALCOORD(3G) 														   GLEVALCOORD(3G)

NAME
glEvalCoord1d,  glEvalCoord1f,  glEvalCoord2d,  glEvalCoord2f,  glEvalCoord1dv,	glEvalCoord1fv,  glEvalCoord2dv, glEvalCoord2fv - evaluate
enabled one- and two-dimensional maps

C SPECIFICATION
void glEvalCoord1d( GLdouble u )
void glEvalCoord1f( GLfloat u )
void glEvalCoord2d( GLdouble u,
GLdouble v )
void glEvalCoord2f( GLfloat u,
GLfloat v )

PARAMETERS
u  Specifies a value that is the domain coordinate u to the basis function defined in a previous glMap1 or glMap2 command.

v  Specifies a value that is the domain coordinate v to the basis function defined in a previous glMap2	command.   This  argument  is  not
present in a glEvalCoord1 command.

C SPECIFICATION
void glEvalCoord1dv( const GLdouble *u )
void glEvalCoord1fv( const GLfloat *u )
void glEvalCoord2dv( const GLdouble *u )
void glEvalCoord2fv( const GLfloat *u )

PARAMETERS
u      Specifies  a pointer to an array containing either one or two domain coordinates.  The first coordinate is u.  The second coordinate
is v, which is present only in glEvalCoord2 versions.

DESCRIPTION
glEvalCoord1 evaluates enabled one-dimensional maps at argument u.  glEvalCoord2 does the same for two-dimensional maps	using  two  domain
values, u and v.  To define a map, call glMap1 and glMap2; to enable and disable it, call glEnable and glDisable.

When  one  of  the  glEvalCoord	commands  is  issued, all currently enabled maps of the indicated dimension are evaluated.  Then, for each
enabled map, it is as if the corresponding GL command had been issued with the computed value.  That is, if GL_MAP1_INDEX or  GL_MAP2_INDEX
is  enabled,  a	glIndex  command  is  simulated.   If  GL_MAP1_COLOR_4	or GL_MAP2_COLOR_4 is enabled, a glColor command is simulated.	If
GL_MAP1_NORMAL or GL_MAP2_NORMAL is enabled, a normal vector 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 exam-
ple, GL_MAP2_TEXTURE_COORD_1 and GL_MAP2_TEXTURE_COORD_2), then only the evaluation of the map that produces the larger number  of  coordi-
nates  (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=__x__

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  nei-
ther 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
glIsEnabled with argument GL_MAP2_INDEX
glIsEnabled with argument GL_MAP2_COLOR_4
glIsEnabled with argument GL_MAP2_NORMAL
glIsEnabled with argument GL_MAP2_TEXTURE_COORD_1
glIsEnabled with argument GL_MAP2_TEXTURE_COORD_2
glIsEnabled with argument GL_MAP2_TEXTURE_COORD_3
glIsEnabled with argument GL_MAP2_TEXTURE_COORD_4
glIsEnabled with argument GL_AUTO_NORMAL
glGetMap

glBegin(3G),  glColor(3G), glEnable(3G), glEvalMesh(3G), glEvalPoint(3G), glIndex(3G), glMap1(3G), glMap2(3G), glMapGrid(3G), glNormal(3G),
glTexCoord(3G), glVertex(3G)

GLEVALCOORD(3G)```