GLMAPGRID(3G) OpenGL Manual GLMAPGRID(3G)
NAME
glMapGrid - 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 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 + 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 execution 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(), glEvalMesh(), glEvalPoint(), glMap1(), glMap2()
COPYRIGHT
Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.
AUTHORS
opengl.org
opengl.org 06/10/2014 GLMAPGRID(3G)