background with alpha unexpected behavior

[jacopomazzoni]

p5.js version

1.9.3

What is your operating system?

Windows

Web browser and version

Brave ( chrome ) 1.66.110 Chromium: 125.0.6422.60 (Official Build) (64-bit)

Actual Behavior

for alpha values < 25 in background some shapes are never fully overwritten

ie: background(0,5) has the issue background(0,25) does not

Expected Behavior

any shape after a certain amount of frames depending on its color should be wiped away by enough overlays no matter how small the transparency

Steps to reproduce

Steps:

1. run this MRE and look at the circle never disappearing
2. change values and observe that ~25 depending on browser and os is the threshold value for shapes finally disappearing
3. fix implementation?

   Snippet:

// https://editor.p5js.org/jacopom/sketches/RU0kHMjnG function setup() { createCanvas(400, 400); background(0);

}

function draw() {

background(0,5); fill(255); stroke(255); if(frameCount == 1 ) { ellipse(width/2,height/2,100); } fill(0); rect(0,0,100,30); fill(255); text("Frame: " + frameCount,20,20);

// / 5 out of 255 alpha / / expected behaviour 255/5 = 51 / / in 51 cycles a white value of / / 255 should be reduced to 0 / / let's test it! / / in reality for any value <~25 this does not happen / / and a faint white dot remains visible forever / // }

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[jacopomazzoni]

I messed up I thought I was opening an issue on the library page, sorry close this.