glEvalMesh1 function

Computes a one-dimensional grid of points or lines.

Syntax

void WINAPI glEvalMesh1(
   GLenum mode,
   GLint  i1,
   GLint  i2
);

Parameters

mode

A value that specifies whether to compute a one-dimensional mesh of points or lines. The following symbolic constants are accepted: GL_POINT and GL_LINE.

i1

The first integer value for grid ___domain variable i.

i2

The last integer value for grid ___domain variable i.

Return value

This function does not return a value.

Error codes

The following error codes can be retrieved by the glGetError function.

Remarks

Use glMapGrid and glEvalMesh together 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 mode parameter determines whether the resulting vertices are connected as points, lines, or filled polygons.

In the one-dimensional case, glEvalMesh1, the mesh is generated as if the following code fragment were executed:

glBegin(type);

for (i = i1; i <= i2; i += 1)

{

glEvalCoord1(i?u + u1)

}

glEnd( );

where

?u = (u2 u1) / n

and n, u1, and u2 are the arguments to the most recent glMapGrid1 function. The type parameter is GL_POINTS if mode is GL_POINT, or GL_LINES if mode is GL_LINE. The one absolute numeric requirement is that if i = n, then the value computed from i?u + u1 is exactly u2.

Requirements

See also

glBegin