glMapGrid

define a one- or two-dimensional mesh

Signature

glMapGrid( )->
glMapGrid1d( GLint ( un ) , GLdouble ( u1 ) , GLdouble ( u2 ) )-> void
glMapGrid1d( un , u1 , u2 )
glMapGrid1f( GLint ( un ) , GLfloat ( u1 ) , GLfloat ( u2 ) )-> void
glMapGrid1f( un , u1 , u2 )
glMapGrid2d( GLint ( un ) , GLdouble ( u1 ) , GLdouble ( u2 ) , GLint ( vn ) , GLdouble ( v1 ) , GLdouble ( v2 ) )-> void
glMapGrid2d( un , u1 , u2 , vn , v1 , v2 )
glMapGrid2f( GLint ( un ) , GLfloat ( u1 ) , GLfloat ( u2 ) , GLint ( vn ) , GLfloat ( v1 ) , GLfloat ( v2 ) )-> void
glMapGrid2f( un , u1 , u2 , vn , v1 , v2 )

Parameters

VariablesDescription
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

Sample Code References

The following code samples have been found which appear to reference the functions described here. Take care that the code may be old, broken or not even use PyOpenGL.

glMapGrid2f
OpenGLContext tests/dek_surf.py Lines: 53
OpenGLContext tests/dek_texturesurf.py Lines: 68
OpenGL-Demo PyOpenGL-Demo/dek/texturesurf.py Lines: 79

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