Allow loading of models from strings

[Kabaril]

Increasing access

• Can help increase portability of examples (as in copy + paste),
• Allows loading models without a server

Most appropriate sub-area of p5.js?

• [ ] Accessibility
• [ ] Color
• [ ] Core/Environment/Rendering
• [ ] Data
• [ ] DOM
• [ ] Events
• [ ] Image
• [ ] IO
• [ ] Math
• [ ] Typography
• [ ] Utilities
• [X] WebGL
• [ ] Build process
• [ ] Unit testing
• [ ] Internationalization
• [ ] Friendly errors
• [ ] Other (specify if possible)

Feature enhancement details

The current loadModel function takes a path to load a model from a .stl or .obj file, however this requires that a server exists that serves these assets.

A function that loads models directly from a string can increase portability of examples (as in copy + paste) and allows loading models without a server.

The following example:

//draw a spinning octahedron
let octahedron;

function preload() {
  octahedron = loadModel('assets/octahedron.obj');
}

function setup() {
  createCanvas(100, 100, WEBGL);
  describe('Vertically rotating 3-d octahedron.');
}

function draw() {
  background(200);
  rotateX(frameCount * 0.01);
  rotateY(frameCount * 0.01);
  model(octahedron);
}

could also be written as:

const octahedron_model = `
v 0.000000E+00 0.000000E+00 40.0000
v 22.5000 22.5000 0.000000E+00
v 22.5000 -22.5000 0.000000E+00
v -22.5000 -22.5000 0.000000E+00
v -22.5000 22.5000 0.000000E+00
v 0.000000E+00 0.000000E+00 -40.0000

f     1 2 3
f     1 3 4
f     1 4 5
f     1 5 2
f     6 5 4
f     6 4 3
f     6 3 2
f     6 2 1
f     6 1 5
`

//draw a spinning octahedron
let octahedron;

function preload() {
  octahedron = loadModelString(octahedron_model, {type: 'obj'});
}

function setup() {
  createCanvas(100, 100, WEBGL);
  describe('Vertically rotating 3-d octahedron.');
}

function draw() {
  background(200);
  rotateX(frameCount * 0.01);
  rotateY(frameCount * 0.01);
  model(octahedron);
}

The changes in code should be trivial, as this can reuse already existing helper functions.

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[davepagurek]

I agree this feature makes sense! Although I would follow the precedent set by shaders, where loadShader is called in preload and loads from a file, and createShader is called in setup and loads from a string. That would imply that we'd have loadModel from a file and createModel from a string.

[mathewpan2]

I'd like to try and work on this.

[mathewpan2]

@davepagurek I implemented the method to load obj/stl from a string, but wonder if this is still up for debate and I was a little premature. Should I make the pr?

[davepagurek]

Feel free to make a PR, thanks!