# Question about AlphaMode
**URL:** https://forum.babylonjs.com/t/question-about-alphamode/60527
**Category:** Questions
**Created:** [September 16, 2025, 8:20am UTC](https://forum.babylonjs.com/t/question-about-alphamode/60527 "2025-09-16T08:20:47Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Moriy](https://forum.babylonjs.com/u/Moriy)
#### Post date: [September 16, 2025, 8:20am UTC](https://forum.babylonjs.com/t/question-about-alphamode/60527/1 "2025-09-16T08:20:47Z")
1. I add a holographic effect in PG, AlphaMode is Add, I have some troubles that when alpha \<0.01 or other value, line will be discard, when alpha increase gl\_FragColor is from none to correct color to pink to white. Why line be discard? Why blend color is pink in progress.
[https://playground.babylonjs.com/#W6EUYR#22](https://playground.babylonjs.com/#W6EUYR#22)
2. I use two effectWrappers to update two ping-pong rtts, could babylonjs render effectWrappers with multi-input-rtts and multi-output-rtts?
---
### Author:  [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)
#### Post date: [September 16, 2025, 10:55am UTC](https://forum.babylonjs.com/t/question-about-alphamode/60527/2 "2025-09-16T10:55:16Z")
Regarding 1/, the output canvas is 8 bits, and you don’t have enough precision to see anything when the alpha is \< 0.01. You can force all rendering to be done in floating point by creating a pass post-process like this:
```typescript
const pass = new BABYLON.PassPostProcess("pass", 1, camera, undefined, undefined, undefined, BABYLON.Constants.TEXTURETYPE_FLOAT);
```
(TEXTURETYPE\_HALF\_FLOAT also works and consumes half the memory)
The conversion to 8 bits is only performed at the end, so you will be able to see the XRay even below 0.01:
> **[Babylon.js Playground](https://playground.babylonjs.com/#W6EUYR%2324)**
>
> Babylon.js playground is a live editor for Babylon.js WebGL and WebGPU 3D scenes
Regarding 2/, `effectRenderer` is meant to be simple and efficient and can only render to a single RTT. You should use a `MultiRenderTarget` if you want to be able to render to multiple textures at once.
---
### Author:  [@Moriy](https://forum.babylonjs.com/u/Moriy)
#### Post date: [September 18, 2025, 1:08am UTC](https://forum.babylonjs.com/t/question-about-alphamode/60527/3 "2025-09-18T01:08:05Z")
> [@Evgeni\_Popov](#):
>
> `.PassPostPr`
Thank you for your help! I will try how to use multiRenderTarget 😆