module:extras/contourlines

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### module:extras/contourlines()

The extras/contourlines.js module. To import all symbols in this module, either of the following can be used:

import * from "extras/contourlines.js";
// -- or --
import * as CustomModuleName from "extras/contourlines.js";

Methods

• contourLines
  Generates contour lines for two-dimensional data, using Paul Bourke’s CONREC algorithm.
• contourLines3D
  Generates a mesh buffer of contour lines along the surface of a 3-dimensional triangle mesh.

### (static) module:extras/contourlines.contourLines(func, levels, u1, u2, v1, v2, usize, vsize)

Generates contour lines for two-dimensional data, using Paul Bourke’s CONREC algorithm.

Parameters

• func (Type: function)
  A function that takes two parameters–a U coordinate and a V coordinate–and returns a number at that point.
• levels (Type: Array.<number>)
  An array of values at which to draw contour lines. For example, if levels is [20, 25], this function will draw contour lines along the values 20 and 25.
• u1 (Type: number)
  Starting U coordinate to sample.
• u2 (Type: number)
  Ending U coordinate to sample.
• v1 (Type: number)
  Starting V coordinate to sample.
• v2 (Type: number)
  Ending V coordinate to sample.
• usize (Type: number)
  The number of levels between grid points along the U axis. This method will sample (usize+1)*(vsize+1) grid points in total.
• vsize (Type: number)
  The number of levels between grid points along the V axis.

Return Value

A mesh buffer of line segments for the contour lines. (Type: MeshBuffer)

Examples

This example generates contour lines for a simple function. This method samples the function at integer grid points.

var mesh=contourLines((u,v)=>(Math.sin((u+v)/6)),
[0, 1, 2, 3],
0,10,0,10,10,10);

### (static) module:extras/contourlines.contourLines3D(mesh, planes)

Generates a mesh buffer of contour lines along the surface of a 3-dimensional triangle mesh.

Parameters

• mesh (Type: MeshBuffer)
  A triangle mesh. It must contain a “POSITION” buffer attribute with three elements per value. If the number of vertices in the mesh is not divisible by 3, any excess vertices at the end are ignored.
• planes (Type: Array.<Array.<number»)
  An array of 4-element arrays that serve as contour planes. The contour lines will be drawn at the intersection of the contour planes and the surface of the mesh. Each 4-element array describes a plane (A, B, C, D), in that order, whose points satisfy the equation Ax + By + Cz + D = 0, where (x, y, z) is a point lying on the plane.

Return Value

A mesh buffer containing the generated contour lines. Returns null if the input mesh’s primitive type isn’t triangles, or if the input mesh doesn’t contain a “POSITION” buffer attribute with three elements per value. (Type: MeshBuffer)

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