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Some newbie questions (ADD BLEND, SOLVED)

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djex
Posts: 11
Joined: Mon Jan 01, 2018 6:28 pm

Some newbie questions (ADD BLEND, SOLVED)

Post by djex »

Hello, nice program!
today I was looking at the samples and did a simple video for reference:
https://www.youtube.com/watch?v=R6mDYbt6ngI
I'm loving the program but I have some questions:
- How to get real additive blending (to simulate light particles), I was trying the Add and other filters using the Starfield generator but the circles never were more bright if they accumulated in the screen.
- How to modify the generators, I mean in example if I want to modify the Starfield to generate a whole circle of stars instead of one star randomly per beat. How could I do that?

Thanks in advance, I could not find this info in a quick search of these forums.
Sadler
Posts: 1139
Joined: Sat Aug 02, 2014 7:10 pm
Location: London, UK

Re: Some newbie questions (ADD BLEND, modify Starfield)

Post by Sadler »

The manual is probably a better place to look for answers on...
Shaders
Starfield
circles never were more bright if they accumulated in the screen
Additive blending of white+white won't give white+ (on most displays), it can only give you white - i.e (1,1,1) + (1,1,1) doesn't give (2,2,2) but (1,1,1). One can simulate bright light using bloom, blur and flares to some extent but these can be processing intensive. 3D renders simulate bloom (Blender's eevee can almost do real-time) but cannot go brighter than white. Some programs can work with brighter than white values but these must be scaled in order to be displayed on screen.
djex
Posts: 11
Joined: Mon Jan 01, 2018 6:28 pm

Re: Some newbie questions (ADD BLEND, modify Starfield)

Post by djex »

Yep, I have read the manuals.
Can you point to a sample showing the additive mode working on different layers?
I was trying different samples and demos found in the forums but none of them works.
I know that white over white additive is white, but when merging additively many layers (not white) the end result must be white, that is not working.
Sadler
Posts: 1139
Joined: Sat Aug 02, 2014 7:10 pm
Location: London, UK

Re: Some newbie questions (ADD BLEND, modify Starfield)

Post by Sadler »

If you're working with multiple layers you will need another Blend module for each additional layer. It would be nice for the Blend module to blend multiple inputs together but currently it works only with two.
additive_blend.magic
Adding the primary colours...
(2.52 KiB) Downloaded 299 times
djex
Posts: 11
Joined: Mon Jan 01, 2018 6:28 pm

Re: Some newbie questions (ADD BLEND, modify Starfield)

Post by djex »

perfect! Oh I see, I was putting the filter before the Output node in every layer, my bad
Thank you.
Magic
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Joined: Wed Apr 09, 2014 9:28 pm

Re: Some newbie questions (ADD BLEND, SOLVED)

Post by Magic »

Specifically for additive blending, you don't need to use the Blend module (but you can if you want).

This tutorial explains how to do it: viewtopic.php?f=3&t=28#p67
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