# blendMode rendering issues p5.js

**URL:** https://discourse.processing.org/t/blendmode-rendering-issues-p5-js/19179
**Category:** Coding Questions
**Created:** [March 30, 2020, 10:22am UTC](https://discourse.processing.org/t/blendmode-rendering-issues-p5-js/19179 "2020-03-30T10:22:45Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![artforart](https://avatars.discourse-cdn.com/v4/letter/a/c77e96/32.png) [@artforart](https://discourse.processing.org/u/artforart)
#### Post date: [March 30, 2020, 10:22am UTC](https://discourse.processing.org/t/blendmode-rendering-issues-p5-js/19179/1 "2020-03-30T10:22:45Z")

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I keep running into performance issues trying to visualize some simplex noise – using about 1700 circle objects. Setting the `blendMode(MULTIPLY)` in the `setup` function has been producing some laggy results. See [this codepen](https://codepen.io/geletina/pen/PoqxNJp) for full code. I’ve lowered the frame but that hasn’t helped. Any ideas why `blendMode` is so computationally taxing? 🙏

```auto
function setup() {
  frameRate(30);
  createCanvas(windowWidth, windowHeight);
  xCoord = round(windowWidth / (cells - 2));
  yCoord = round(windowHeight / (cells - 2));
  blue = color("rgba(2,128,215,0.75)");
  pink = color("rgba(228,15,41,0.75)");
  yellow = color("rgba(246,232,0,0.75)");
  blendMode(MULTIPLY);
}

```

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<div class="post-metadata">

### Author: ![jeremydouglass](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/jeremydouglass/32/20_2.png) [@jeremydouglass](https://discourse.processing.org/u/jeremydouglass)
#### Post date: [April 5, 2020, 6:41pm UTC](https://discourse.processing.org/t/blendmode-rendering-issues-p5-js/19179/2 "2020-04-05T18:41:32Z")

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> [@artforart](#):
>
> Any ideas why `blendMode` is so computationally taxing?

I’m not sure – you could check out the test sketches and the definition in p5.js core –

- [Repository search results · GitHub](https://github.com/processing/p5.js/search?q=blendmode&unscoped_q=blendmode)
- [https://github.com/processing/p5.js/search?q=multiply&unscoped\_q=multiply](https://github.com/processing/p5.js/search?q=multiply&unscoped_q=multiply)