HP b2600 Reference Manual page 280

M
glMap2
Equation 11-8
glMap2 is used to define the basis and to specify what kind of values are produced. Once
defined, a map can be enabled and disabled by calling glEnable and glDisable with the
map name, one of the nine predefined values for target, described below.
WhenglEvalCoord2 presents values u and v, the bivariate Bernstein polynomials are
evaluated using û and v, where
Equation 11-9
target is a symbolic constant that indicates what kind of control points are provided in
points, and what output is generated when the map is evaluated. It can assume one of
nine predefined values:
GL_MAP2_VERTEX_3
Each control point is three floating-point values representing x, y, and z. Internal
glVertex3 commands are generated when the map is evaluated.
GL_MAP2_VERTEX_4
Each control point is four floating-point values representing x, y, z, and w. Internal
glVertex4 commands are generated when the map is evaluated.
GL_MAP2_INDEX
Each control point is a single floating-point value representing a color index. Internal
glIndex commands are generated when the map is evaluated but the current index is not
updated with the value of these glIndex commands.
GL_MAP2_COLOR_4
Each control point is four floating-point values representing red, green, blue, and alpha.
Internal glColor4 commands are generated when the map is evaluated but the current
color is not updated with the value of these glColor4 commands.
GL_MAP2_NORMAL
Each control point is three floating-point values representing the x, y, and z components
of a normal vector. Internal glNormal commands are generated when the map is
evaluated but the current normal is not updated with the value of these glNormal
commands.
GL_MAP2_TEXTURE_COORD_1
Each control point is a single floating-point value representing the s texture coordinate.
Internal glTexCoord1 commands are generated when the map is evaluated but the
current texture coordinates are not updated with the value of these glTexCoord
commands.
GL_MAP2_TEXTURE_COORD_2
280
n
0
0 1and 1
0
u u1 –
u ˆ = ----------------- -
u2 u1 –
v v1 –
v ˆ ----------------- -
=
v2 v1 –
Chapter 11