Calling loadModel while a custom shader is in use breaks the existing shader.

[sflanker]

Most appropriate sub-area of p5.js?

• [ ] Accessibility (Web Accessibility)
• [ ] Build tools and processes
• [ ] Color
• [ ] Core/Environment/Rendering
• [ ] Data
• [ ] DOM
• [ ] Events
• [ ] Friendly error system
• [ ] Image
• [ ] IO (Input/Output)
• [ ] Localization
• [ ] Math
• [ ] Unit Testing
• [ ] Typography
• [ ] Utilities
• [X] WebGL
• [ ] Other (specify if possible)

Details about the bug:

• p5.js version: 1.4.0
• Web browser and version: Chromium: 94.0.4606.71 & Firefox 93.0
• Operating System: MacOS 10.15.7
• Steps to reproduce this:

1. Load a model
2. Load a shader
3. Draw the model with the shader
4. Load another model
5. Try to draw anything with the existing shader

The root cause is that calls to loadModel() outside of preload() are causing setup() to get called a second time. This should not happen! There is something wrong with the preload wrapper function for some if not all load*** calls (specifically it is looking for _setupDone in the wrong place (or _setupDone is being set to true in the wrong place) for sketches in global mode

let model1;
let model2;
let shader1;

function preload() {
  model1 = loadModel("teapot.obj", true);
  shader1 = loadShader("shader.vert", "shader.frag");
}

let i = 0;
function setup() {
  console.log(`setup called ${i++}`);
  createCanvas(windowWidth, windowHeight, WEBGL);
  noLoop();
  noStroke();

  background(255);
  scale(1, -1, 1);
  shader(shader1);
  model(model1);
}

function doubleClicked() {
  if (!model2) {
    model2 = loadModel("gourd.obj", false, () => {
      console.log("loaded");
      background("green");
      // broken!
      model(model1);
    });
  }
}

https://editor.p5js.org/Kumu-Paul/sketches/rmpqtMN-X