gl-simplicial-complex

Basic module for drawing a simplicial complex. This code can be used to get something on the screen quickly. It is useful for debugging and prototyping, though in a real 3d engine you would probably want to write your own shaders and vertex formats.

Example

var shell = require("gl-now")()
var camera = require("game-shell-orbit-camera")(shell)
var mat4 = require("gl-matrix").mat4
var bunny = require("bunny")
var createSimplicialComplex = require("gl-simplicial-complex")

var mesh

shell.on("gl-init", function() {
  var gl = shell.gl
  gl.enable(gl.DEPTH_TEST)
  bunnyMesh = createSimplicialComplex(gl, bunny)
})

shell.on("gl-render", function() {
  bunnyMesh.draw({
    view: camera.view(),
    projection: mat4.perspective(mat4.create(),
          Math.PI/4.0,
          shell.width/shell.height,
          0.1,
          1000.0)
  })
})

Try out the example in your browser

Install

npm instal gl-simplicial-complex

API

var createSimplicialComplex = require("gl-simplicial-complex")

`var mesh = createSimplicialComplex(gl, params)`

Creates a simplicial complex that can be drawn directly in a WebGL context.

gl - is a handle to a WebGL context
params is an object that has the following properties:
- cells (Required) An indexed list of vertices, edges and/or faces.
- positions (Required) An array of positions for the mesh, encoded as arrays
- vertexColors A list of per vertex color attributes encoded as length 3 rgb arrays
- vertexUVs
- cellUVs
- vertexIntensity
- cellIntensity
- cellColors A list of per cell color attributes
- meshColor A constant color for the entire mesh
- vertexNormals An array of per vertex normals
- cellNormals An array of per cell normals
- useFacetNormals A flag which if set to true forces cellNormals to be computed
- pointSizes An array of point sizes
- pointSize A single point size float
- ambientLight
- diffuseLight
- specularLight
- lightPosition
- roughness
- fresnel

Returns A renderable mesh object

`mesh.draw(params)`

Draws the mesh to the current buffer using a Phong material.

params is an object that has the following properties
- model The model matrix for the object
- view The view matrix for the camera
- projection The projection matrix for the display

`mesh.update(params)`

Updates the contents of the simplicial complex in place.

params is a list of parameters which are in the same format as createSimplicialComplex

`mesh.drawPick(params)`

Draws the mesh for the purposes of point picking and selection.

`mesh.pick(pickData)`

Using the output from gl-select finds the point on the mesh closest to the given pick data.

Returns An object with the following properties:

positions the position of the picked point on the mesh
cellId the index of the closest cell
cell the cell of the closest point
index the index of the closest vertex

`mesh.dispose()`

Destroys the mesh object and releases all resources assigned to it.

Package detail