GLMAPGRID(3G) UNIX Programmer's Manual GLMAPGRID(3G)
NAME
glMapGrid1d, glMapGrid1f, glMapGrid2d, glMapGrid2f - define
a one- or two-dimensional mesh
C SPECIFICATION
void glMapGrid1d( GLint un,
GLdouble u1,
GLdouble u2 )
void glMapGrid1f( GLint un,
GLfloat u1,
GLfloat u2 )
void glMapGrid2d( GLint un,
GLdouble u1,
GLdouble u2,
GLint vn,
GLdouble v1,
GLdouble v2 )
void glMapGrid2f( GLint un,
GLfloat u1,
GLfloat u2,
GLint vn,
GLfloat v1,
GLfloat v2 )
PARAMETERS
un Specifies the number of partitions in the grid range
interval [u1, u2]. Must be positive.
u1, u2
Specify the mappings for integer grid domain values
i = 0 and i = un.
vn Specifies the number of partitions in the grid range
interval [v1, v2]
(glMapGrid2 only).
v1, v2
Specify the mappings for integer grid domain values
j = 0 and j = vn
(glMapGrid2 only).
DESCRIPTION
glMapGrid and glEvalMesh are used together to efficiently
generate and evaluate a series of evenly-spaced map domain
values. glEvalMesh steps through the integer domain of a
one- or two-dimensional grid, whose range is the domain of
the evaluation maps specified by glMap1 and glMap2.
glMapGrid1 and glMapGrid2 specify the linear grid mappings
between the i (or i and j) integer grid coordinates, to the
MirBSD #10-current Printed 2021-12-07 1
GLMAPGRID(3G) UNIX Programmer's Manual GLMAPGRID(3G)
u (or u and v) floating-point evaluation map coordinates.
See glMap1 and glMap2 for details of how u and v coordinates
are evaluated.
glMapGrid1 specifies a single linear mapping such that
integer grid coordinate 0 maps exactly to u1, and integer
grid coordinate un maps exactly to u2. All other integer
grid coordinates i are mapped so that
u = i(u2-u1)/un + u1
glMapGrid2 specifies two such linear mappings. One maps
integer grid coordinate i = 0 exactly to u1, and integer
grid coordinate i = un exactly to u2. The other maps integer
grid coordinate j = 0 exactly to v1, and integer grid coor-
dinate j = vn exactly to v2. Other integer grid coordinates
i and j are mapped such that
u = i(u2-u1)/un + u1
v = j(v2-v1)/vn + v1
The mappings specified by glMapGrid are used identically by
glEvalMesh and glEvalPoint.
ERRORS
GL_INVALID_VALUE is generated if either un or vn is not
positive.
GL_INVALID_OPERATION is generated if glMapGrid is executed
between the execution of glBegin and the corresponding exe-
cution of glEnd.
ASSOCIATED GETS
glGet with argument GL_MAP1_GRID_DOMAIN
glGet with argument GL_MAP2_GRID_DOMAIN
glGet with argument GL_MAP1_GRID_SEGMENTS
glGet with argument GL_MAP2_GRID_SEGMENTS
SEE ALSO
glEvalCoord(3G), glEvalMesh(3G), glEvalPoint(3G),
glMap1(3G), glMap2(3G)
MirBSD #10-current Printed 2021-12-07 2