glMapGrid(3G)glMapGrid(3G)NAME
glMapGrid, glMapGrid1d, glMapGrid1f, glMapGrid2d, glMapGrid2f - define
a one- or two-dimensional mesh
SYNOPSIS
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
Specifies the number of partitions in the grid range interval [u1, u2].
Must be positive. Specify the mappings for integer grid domain values
i=0 and i="un". Specifies the number of partitions in the grid range
interval [v1, v2] (glMapGrid2() only). Specify the mappings for inte‐
ger grid domain values j=0 and j="vn" (glMapGrid2() only).
DESCRIPTIONglMapGrid() 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 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 coordinate 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 + uv1
The mappings specified by glMapGrid() are used identically by glE‐
valMesh() 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 execution of glEnd().
ASSOCIATED GETSglGet() 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 ALSOglEvalCoord(3), glEvalMesh(3), glEvalPoint(3), glMap1(3), glMap2(3)glMapGrid(3G)
