---

Manual Reference Pages  - GLMAPGRID (3G)

---

glMapGrid1d, glMapGrid1f, glMapGrid2d, glMapGrid2f - define a one- or two-dimensional mesh

CONTENTS

C Specification
Parameters
Description
Errors
Associated Gets
See Also

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 )

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).

 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.

 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.

 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

 glEvalCoord(3G),  glEvalMesh(3G),  glEvalPoint(3G),  glMap1(3G),  glMap2(3G)

Jump to page    or go to Top of page |  Section 3G |  Main Index.