Gl.MapGrid2f (gb.opengl)

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 $\mathit{i}<code\; style="white-space:nowrap;"></code>\; <mn>0</mn>$ and $\mathit{i}<code\; style="white-space:nowrap;"></code>\; <mi\; mathvariant="italic">un</mi>$.

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 $\mathit{j}<code\; style="white-space:nowrap;"></code>\; <mn>0</mn>$ and $\mathit{j}<code\; style="white-space:nowrap;"></code>\; <mi\; mathvariant="italic">vn</mi>$ (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 $\mathit{i}$ (or $\mathit{i}$ and $\mathit{j}$) integer grid coordinates, to the $\mathit{u}$ (or $\mathit{u}$ and $\mathit{v}$) floating-point evaluation map coordinates. See Gl.Map1 and Gl.Map2 for details of how $\mathit{u}$ and $\mathit{v}$ 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 $\mathit{i}$ are mapped so that

Gl.MapGrid2 specifies two such linear mappings. One maps integer grid coordinate $\mathit{i}<code\; style="white-space:nowrap;"></code>\; <mn>0</mn>$ exactly to u1, and integer grid coordinate $\mathit{i}<code\; style="white-space:nowrap;"></code>\; <mi\; mathvariant="italic">un</mi>$ exactly to u2. The other maps integer grid coordinate $\mathit{j}<code\; style="white-space:nowrap;"></code>\; <mn>0</mn>$ exactly to v1, and integer grid coordinate $\mathit{j}<code\; style="white-space:nowrap;"></code>\; <mi\; mathvariant="italic">vn</mi>$ exactly to v2. Other integer grid coordinates $\mathit{i}$ and $\mathit{j}$ are mapped such that

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

See original documentation on OpenGL website