Incorrect mixing in Glare node #74680

New Issue

Marcin Twarowski · 2020-03-12T13:02:10+01:00

Marcin Twarowski commented

2020-03-12 13:02:10 +01:00

System Information
Operating system: Windows-10-10.0.16299-SP0 64 Bits
Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.86

Blender Version
Broken: version: 2.83 (sub 8), branch: master, commit date: 2020-03-12 00:33, hash: 8751af6d19
Worked: Never (2.79+)

Short description of error
Glare node with mix between -1 and 0 will brighten entire image

Exact steps for others to reproduce the error

See attached file:
glare_bug.blend
First set Mix value to 1 and render to see only effect

Setting Mix to 0 is supposed to give a middle point between original and processed image. You can see that the background is not brightened:
Render image.
Mix set to -1 essentially disables glare. The background is also not brightened:
Render image.
Set Mix is set to -0.5
Render image. You can see that glare brightened entire image - this should not happen

**System Information** Operating system: Windows-10-10.0.16299-SP0 64 Bits Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.86 **Blender Version** Broken: version: 2.83 (sub 8), branch: master, commit date: 2020-03-12 00:33, hash: `8751af6d19` Worked: Never (2.79+) **Short description of error** Glare node with mix between -1 and 0 will brighten entire image **Exact steps for others to reproduce the error** See attached file: [glare_bug.blend](https://archive.blender.org/developer/F8402170/glare_bug.blend) First set **Mix** value to 1 and render to see only effect - Setting **Mix** to **0** is supposed to give a middle point between original and processed image. You can see that the background is not brightened: - Render image. ![glare_bug_02.png](https://archive.blender.org/developer/F8402176/glare_bug_02.png) - **Mix** set to **-1** essentially disables glare. The background is also not brightened: - Render image. ![glare_bug_03.png](https://archive.blender.org/developer/F8402178/glare_bug_03.png) - Set **Mix** is set to **-0.5** - Render image. You can see that glare brightened entire image - this should not happen ![glare_bug_01.png](https://archive.blender.org/developer/F8402171/glare_bug_01.png)

Marcin Twarowski commented

2020-03-12 13:02:10 +01:00

Added subscriber: @MarcinTwarowski

Germano Cavalcante commented

2020-03-12 17:30:29 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-03-12 17:30:29 +01:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Germano Cavalcante commented

2020-03-12 17:30:29 +01:00

I don't understand what the issue is here.
The mix is between -1 and 1.

A value of -1 would give just the original image, 0 gives a 50/50 mix, and 1 gives just the effect.

The images you showed show what Glare is intended to do.

The Glare node is used to add lens flares, fog, glows around exposed parts of an image and much more.

source

I don't understand what the issue is here. The mix is between -1 and 1. > A value of -1 would give just the original image, 0 gives a 50/50 mix, and 1 gives just the effect. The images you showed show what Glare is intended to do. > The Glare node is used to add lens flares, fog, glows around exposed parts of an image and much more. [source ](https://docs.blender.org/manual/en/dev/compositing/types/filter/glare.html)

Marcin Twarowski commented

2020-03-12 17:34:27 +01:00

At Mix -0.5, the background is brightened, when only the emmisive part should be. Quickly switch between first two images. At mix = 0 it does not happen.