Gambas Documentation - /comp/gb.opengl/gl/mapgrid1f

# Gl.MapGrid1f (gb.opengl)

Static Sub MapGrid1f ( Un As Integer, U As Float, V As Float )

Define a one- or two-dimensional mesh.

### Parameters

un

  Specifies the number of partitions in the grid range interval /wiki/_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 /wiki/_v1_, _v2_ (Gl.MapGrid2 only).

v1, v2

  Specify the mappings for integer grid domain values j `` 0 and j `` vn (Gl.MapGrid2 only).

### Description

Gl.MapGrid and Gl.EvalMesh are used together to efficiently generate and evaluate a series of evenly-spaced map domain values. Gl.EvalMesh steps through the integer domain of a one- or two-dimensional grid, whose range is the domain of the evaluation maps specified by Gl.Map1 and Gl.Map2.

Gl.MapGrid1 and Gl.MapGrid2 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 Gl.Map1 and Gl.Map2 for details of how u and v coordinates are evaluated.

Gl.MapGrid1 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

Gl.MapGrid2 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 Gl.MapGrid are used identically by Gl.EvalMesh and Gl.EvalPoint.

### Errors

Gl.INVALID_VALUE is generated if either un or vn is not positive.

Gl.INVALID_OPERATION is generated if Gl.MapGrid is executed between the execution of Gl.Begin and the corresponding execution of Gl.End.

### Associated Gets

Gl.Get with argument Gl.MAP1_GRID_DOMAIN

Gl.Get with argument Gl.MAP2_GRID_DOMAIN

Gl.Get with argument Gl.MAP1_GRID_SEGMENTS

Gl.Get with argument Gl.MAP2_GRID_SEGMENTS

### See also

Gl.EvalCoord, Gl.EvalMesh, Gl.EvalPoint, Gl.Map1, Gl.Map2

See original documentation on OpenGL website