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Particle System Random Color in C#.

Discussion in 'General Graphics' started by username132323232, Nov 26, 2018.

  1. username132323232

    username132323232

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    In Particle System main module, there is an option "Random Color" for Start Color. Is it possible to set it in C#? Thanks.
     
    username132323232, Nov 26, 2018
    #1

  2. richardkettlewell

    richardkettlewell

    Unity Technologies

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    richardkettlewell, Nov 26, 2018
    #2
    fnnbrr, Musabbir, username132323232 and 1 other person like this.

  3. username132323232

    username132323232

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    Thank you for the reply. I must be doing something wrong, but what I get doesn't look like random color. Each particle gets its color from left to right. So, if I have a 10-seconds particle system, I get green circles for the first 5 seconds and red circles for the next 5 seconds. This seems to be regular gradient not random color behavior. Here is my code:

    Code (CSharp):
    1.        ParticleSystem currentParticleSystem = instance.GetComponent<ParticleSystem>();
    2.         ParticleSystem.MainModule psMain = currentParticleSystem.main;
    3.  
    4.         psMain.startColor = new ParticleSystem.MinMaxGradient(particleSystemGradient);
    5.         var mode = psMain.startColor.mode;
    6.         mode = ParticleSystemGradientMode.RandomColor;
    7.  
     
    username132323232, Nov 27, 2018
    #3

  4. richardkettlewell

    richardkettlewell

    Unity Technologies

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    You are only changing your local variable "mode" by doing it that way. You need to assign it back to the MinMaxGradient. But that type is a struct so the obvious code won't work:
    Code (CSharp):
    1. psMain.startColor.mode = ParticleSystemGradientMode.RandomColor;
    Instead, rewrite the whole thing like this:
    Code (CSharp):
    1. var randomColors = new ParticleSystem.MinMaxGradient(particleSystemGradient);
    2. randomColors.mode = ParticleSystemGradientMode.RandomColor;
    3. psMain.startColor = randomColors;
     
    richardkettlewell, Nov 27, 2018
    #4
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  5. username132323232

    username132323232

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    That's beautiful! Thank you Richard!
     
    username132323232, Nov 27, 2018
    #5
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  6. petey

    petey

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    Hi I'm stuck with a similar problem, just trying to set two random start colours for a particle system.
    Code (CSharp):
    1.             var main = myParticleSystem.main.startColor;
    2.             main.mode = ParticleSystemGradientMode.TwoColors;
    3.             main.colorMax = Color.red;
    4.             main.colorMax = Color.blue;
    Should something like that work?
    Thanks,
    Pete
     
    Last edited: Mar 29, 2019
    petey, Mar 29, 2019
    #6
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  7. richardkettlewell

    richardkettlewell

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    You used colorMax twice and you didn't reassign the gradient back to the startColor property of the particle system. You could fix it up, but a simpler way to write this is to use the ParticleSystemMinMaxGradient constructor that takes 2 colors and sets the mode/colors up for you:
    Code (CSharp):
    1. var main = myParticleSystem.main;
    2. main.startColor = new ParticleSystem.MinMaxGradient(Color.red, Color.blue);
     
    richardkettlewell, Mar 29, 2019
    #7

  8. petey

    petey

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    petey, Mar 29, 2019
    #8
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  9. Livealot

    Livealot

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    This gem should get into the scripting docs
     
    Livealot, May 23, 2019
    #9
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  10. Kaldrin

    Kaldrin

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    Thank you !
    I was wondering why I couldn't reassign the particleSystem.MainModule as it was only read-only, but it's a reference variable so it works fine actually!
     
    Kaldrin, Apr 23, 2021
    #10
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  11. unity_PwXfMGmzHmDcsw

    unity_PwXfMGmzHmDcsw

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    Hi Richard, when I do this is says "particleSystemGradient" doesn't exist in this context. I have googled trying to find a reference to this "particleSystemGradient" but can't, or rather is just points me back to the unhelpful documentation.
     
    unity_PwXfMGmzHmDcsw, Feb 7, 2023
    #11

  12. halley

    halley

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    The 
    particleSystemGradient
    was a variable which @username132323232 had in their own code, not something Unity provided, and then @richardkettlewell continued to use that name because it was working for them.

    Declare a variable in your class of this type, and use it. Change the colors as desired in the Inspector.

    public Gradient particleSystemGradient;


    https://docs.unity3d.com/ScriptReference/Gradient.html
     
    halley, Feb 7, 2023
    #12
    unity_PwXfMGmzHmDcsw and richardkettlewell like this.