mouseButton on touch device gives 0 for first click (and for any long presses before the first click)

[eyaler]

Most appropriate sub-area of p5.js?

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

p5.js version

1.11.1

Web browser and version

firefox 133 android, chrome 131 android

Operating system

android

Steps to reproduce this

mouseButton on touch device gives 0 for first click (and for any long presses before the first click). only presses after that first click give 'left'.

Steps:

1. run on a touch device
2. note that the first click shows mouseButton value to be 0
3. note that only on second click it changes to 'left'
4. rerun and now do long presses instead of clicks. note that the value is 0 until you do the second click

Snippet:

function setup() {
  createCanvas(100, 100)
}

function touchStarted() {
  background(200)
  text(mouseButton, 50, 50)
}

or run this

[wayneharish10]

As we can see from code, touchStarted doesn't set mouseButton, adding a line should solve this issue. @davepagurek thoughts on this? @eyaler, Meanwhile mousePressed function can be used as a workaround.

p5.prototype._ontouchstart = function(e) {
  const context = this._isGlobal ? window : this;
  let executeDefault;
  this._setProperty('mouseIsPressed', true);
  this._updateTouchCoords(e);
  this._updateNextMouseCoords(e);
  this._updateMouseCoords(); // reset pmouseXY at the start of each touch event


  if (typeof context.touchStarted === 'function') {
    executeDefault = context.touchStarted(e);
    if (executeDefault === false) {
      e.preventDefault();
    }

[eyaler]

@wayneharish10 thanks! Due to #7195 I cannot use mousePressed(). IIUC, it would only be called on release for short click and not at all for long press. I am actually calling mousePressed() my self from touchStart() to overcome that, and allow a unified interface.

[davepagurek]

This looks like something that might get resolved in p5 2.0 due to this change #7378 which handles both mouse and touch events using the browser's pointer API rather than trying to handle both separately.

[wayneharish10]

Thanks @davepagurek. Saw the changes made in #7378 myself and I think it'll do.