glMapGrid2d function
Defines a one-dimensional mesh.
Syntax
void WINAPI glMapGrid2d(
GLint un,
GLdouble u1,
GLdouble u2,
GLint vn,
GLdouble v1,
GLdouble v2
);
Parameters
-
un
-
The number of partitions in the grid range interval [u1, u2]. This value must be positive.
-
u1
-
A value used as the mapping for integer grid domain value i = 0.
-
u2
-
A value used as the mapping for integer grid domain value i = un.
-
vn
-
The number of partitions in the grid range interval [v1, v2].
-
v1
-
A value used as the mapping for integer grid domain value j = 0.
-
v2
-
A value used as the mapping for integer grid domain value j = vn.
Return value
This function does not return a value.
Error codes
The following error codes can be retrieved by the glGetError function.
| Name | Meaning |
|---|---|
|
Either un or vn was not positive. |
|
The function was called between a call to glBegin and the corresponding call to glEnd. |
Remarks
The glMapGrid and glEvalMesh functions are used in tandem to efficiently generate and evaluate a series of evenly spaced map domain values. The glEvalMesh function 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.
The glMapGrid1 and glMapGrid2 functions 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.
The glMapGrid1 function 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 such that:
u = i(u2 u1)/un + u1
The glMapGrid2 function 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.
The following functions retrieve information related to glMapGrid:
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
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows 2000 Professional [desktop apps only] |
| Minimum supported server |
Windows 2000 Server [desktop apps only] |
| Header |
|
| Library |
|
| DLL |
|