Particle Effect For UGUI (UI Particle)

This plugin provide a component to render particle effect for uGUI in Unity 2018.2 or later.
The particle rendering is maskable and sortable, without Camera, RenderTexture or Canvas.

<< Description | Demo | Installation | Usage | Development Note | Change log >>

Description

This plugin uses new APIs MeshBake/MashTrailBake (added with Unity 2018.2) to render particles by CanvasRenderer. You can mask and sort particles for uGUI without Camera, RenderTexture, Canvas.

Compares this "Baking mesh" approach with the conventional approach:
Performance test results

Approach	Good	Bad	Screenshot
Baking mesh UIParticle	Rendered as is. Maskable. Sortable. Less objects.	Not support TEXCOORD*.zw components for custom vertex stream
Do nothing	Rendered as is.	Looks like a glitch. Not maskable. Not sortable.
Convert particle to UIVertex UIParticleSystem	Maskable. Sortable. Less objects.	Adjustment is difficult. Requires UI shaders. Difficult to adjust scale. Force hierarchy scalling. Simulation results are incorrect. Trail, rotation of transform, time scaling are not supported. Generate heavy GC every frame.
Use Canvas to sort	Rendered as is. Sortable.	You must to manage sorting orders. Not maskable. More batches.
Use RenderTexture	Maskable. Sortable.	Requires Camera and RenderTexture. Difficult to adjust position and size. Quality depends on the RenderTexture's setting.

Approach	FPS on Editor	FPS on iPhone6	FPS on Xperia XZ
Particle System	43	57	22
UIParticleSystem	4	3	0 (unmeasurable)
Sorting By Canvas	43	44	18
UIParticle	17	12	4
UIParticle with MeshSharing	44	45	30

Features

• Easy to use: the package is out-of-the-box
• Sort particle effects and UI by sibling index
• No Camera, RenderTexture or Canvas are required
• Masking by Mask or RectMask2D
• Support Trail module
• Support CanvasGroup alpha
• No allocations
• Support overlay, camera space and world space
• Support Universal Render Pipeline (URP) and High Definition Render Pipeline (HDRP)
• Support disabling Enter Play Mode Options > Reload Domain
• Support changing material property with AnimationClip (AnimatableProperty)
  
• [4.0.0+] Support 8+ materials
• [4.0.0+] Correct world space particle position when changing window size for standalone platforms (Windows, MacOSX and Linux)
• [4.0.0+] Adaptive scaling for UI
• [4.0.0+] Mesh sharing group to improve performance
  
• [4.0.0+] Particle attractor component
  
• [4.1.0+] Relative/Absolute particle position mode
  

Demo

• WebGL Demo

• WebGL Demo (Cartoon FX & War FX)
  • Cartoon FX Free & War FX (by Jean Moreno (JMO)) with UIParticle

Installation

Requirement

Unity 2018.2 or later

Install via OpenUPM

This package is available on OpenUPM. It's recommended to install it via openupm-cli.

openupm add com.coffee.ui-particle

Install via Package Manager Window (using Git URL)

1. Select Window/Package Manager menu to open Package Manager window.
2. Click + and Install package from git URL...
   
3. Input https://github.com/mob-sakai/ParticleEffectForUGUI.git and click Install
   

Or, use UpmGitExtension to install and update the package.

Install via manifest.json (using Git URL)

1. Open Packages/manifest.json in your project.
2. Add this line below "dependencies": {

• "com.coffee.ui-particle": "https://github.com/mob-sakai/ParticleEffectForUGUI.git",
  

3. To update the package, change suffix #{version}.

• "com.coffee.ui-particle": "https://github.com/mob-sakai/ParticleEffectForUGUI.git#4.2.0",

Install as an embed package

1. Download a source code zip file from Releases page
2. Extract it and place it under Packages directory in your project.
   

How to play demo

For Unity 2019.1 or later

1. Open Package Manager window
2. Select UI Particle package in package list
3. Click Import Sample button
   
4. The demo project is imported into Assets/Samples/UI Particle/{version}/Demo
5. Open UIParticle_Demo scene and play it

For Unity 2018.4 or earlier

1. Select Assets/Samples/UI Particle Demo from menu
2. The demo project is imported into Assets/Samples/UI Particle/{version}/Demo
3. Open UIParticle_Demo scene and play it

About Cartoon FX & War Fx Demo

• It requires free assets (Cartoon FX Free & War FX)
  • by Jean Moreno (JMO)

Usage

UIParticle component

UIParticle controls the ParticleSystems that is attached to its own game objects and child game objects.

Properties	Description
Maskable	Does this graphic allow masking.
Scale	Scale the rendering. When the 3D toggle is enabled, 3D scale (x,y,z) is supported.
Animatable Properties	If you want update material properties (e.g. _MainTex_ST, _Color) in AnimationClip, use this to mark the changes.
Mesh Sharing	Particle simulation results are shared within the same group. A large number of the same effects can be displayed with a small load. When the Random toggle is enabled, it will be grouped randomaly.
Position Mode	Absolute: Emit from the world position of the ParticleSystem. Relative: Emit from the scaled position of the ParticleSystem.
Auto Scaling	Transform.lossyScale (=world scale) will be set to (1, 1, 1) on update. It prevents the root-Canvas scale from affecting the hierarchy-scaled ParticleSystem.
Rendering Order	The ParticleSystem list to be rendered. You can change the order and the materials.

NOTE: Press Refresh button to reconstruct rendering order based on children ParticleSystem's sorting order and z position.

Basically usage

1. Select Game Object/UI/ParticleSystem to create UIParticle with a ParticleSystem.
   
2. Adjust the ParticleSystem as you like.
   

With your existing ParticleSystem prefab

1. Select Game Object/UI/ParticleSystem (Empty) to create UIParticle.
   
2. Drag & drop your ParticleSystem prefab on UIParticle.
   

With Mask or RectMask2D component

If you want to mask particles, set a stencil supported shader (such as UI/UIAdditive) to material for ParticleSystem. If you use some custom shaders, see How to make a custom shader to support Mask/RectMask2D component section.

Script usage

// Instant ParticleSystem prefab with UIParticle on runtime.
var go = GameObject.Instantiate(prefab);
var uiParticle = go.AddComponent<UIParticle>();

// Control by ParticleSystem.
particleSystem.Play();
particleSystem.Emit(10);

// Control by UIParticle.
uiParticle.Play();
uiParticle.Stop();

UIParticleAttractor component

UIParticleAttractor attracts particles generated by the specified ParticleSystem.

Properties	Description
Particle System	Attracts particles generated by the specified particle system.
Distination Radius	Once the particle is within the radius, the particle lifetime will become 0 and OnAttracted will be called.
Delay Rate	Delay to start attracting. It is a percentage of the particle's start lifetime.
Max Speed	Maximum speed of attracting. If this value is too small, attracting may not be completed by the end of the lifetime and OnAttracted may not be called.
Movement	Attracting movement type. (Linear, Smooth, Sphere)
Update Mode	Normal: Update with scaled delta time. Unscaled Time: Update with unscaled delta time.
OnAttracted	An event called when attracting is complete (per particle).

Development Note

FAQ: Why are my particle effects not displayed correctly?

If ParticleSystem alone displays particles correctly but UIParticle does not, please check the following points:

• Shader Limitation
  • Most cases can be solved by using UI/Additive or UI/Default.
• Particles are masked
  • UIParticle is maskable.
  • Set Mask or RectMask2D component properly.
• Particles are too small
  • If particles are small enough, they will not appear on the screen.
  • Increase the Scale value.
  • If you don't want to change the apparent size depending on the resolution, try Auto Scaling option.
• Particles are too many
  • No more than 65535 vertices can be displayed (for mesh combination limitations).
  • Please set Emission module and Max Particles of ParticleSystem properly.
• Particles are emitted off-screen.
  • When Position Mode = Relative, particles are emitted from scaled position of the ParticleSystem, not from the screen point of the ParticleSystem.
  • Place the ParticleSystem in the proper position or try Position Mode = Absolute.
• Attaching UIParticle to the same object as ParticleSystem
  • Transform.localScale will be overridden by Auto Scaling option.
  • It is recommended to place ParticleSystem under UIParticle.

Shader Limitation

The use of UI shaders is recommended.

• If you need a simple Additive shader, use the UI/Additive shader instead.
• If you need a simple alpha-blend shader, use the UI/Default shader instead.
• If your custom shader does not work properly with UIParticle, consider creating a custom UI shader.

Built-in shaders are not supported

UIParticle does not support all built-in shaders except for UI/Default.
If their use is detected, an error is displayed in the inspector.
Use UI shaders instead.

UV.zw components will be discarded

UIParticleRenderer renders the particles based on UIVertex.
Therefore, only xy components is available for each UV in the shader. (zw components will be discarded).
So unfortunately UIParticles will not work well with some shaders.

Custom vertex streams

When using custom vertex streams, you can fill zw components with "unnecessary" data.
https://github.com/mob-sakai/ParticleEffectForUGUI/issues/191

Overheads

UIParticle has some overheads and the batching depends on uGUI.
When improving performance, keep the following in mind:

• If you are displaying a large number of the same effect, consider Mesh Sharing feature in UIParticle Component.
  • If you don't like the uniform output, consider Random Group feature.
    
• If you are using multiple materials, you will have more draw calls.
  • Consider single material, atlasing the sprites, and using Sprite mode in the Texture Sheet Animation module in ParticleSystem.

How to make a custom shader to support Mask/RectMask2D component

Shader tips

Shader "Your/Custom/Shader"
{
    Properties
    {
        // ...
        // #### required for Mask ####
        _StencilComp ("Stencil Comparison", Float) = 8
        _Stencil ("Stencil ID", Float) = 0
        _StencilOp ("Stencil Operation", Float) = 0
        _StencilWriteMask ("Stencil Write Mask", Float) = 255
        _StencilReadMask ("Stencil Read Mask", Float) = 255
        _ColorMask ("Color Mask", Float) = 15
        [Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip ("Use Alpha Clip", Float) = 0
    }

    SubShader
    {
        Tags
        {
            // ...
        }

        // #### required for Mask ####
        Stencil
        {
            Ref [_Stencil]
            Comp [_StencilComp]
            Pass [_StencilOp]
            ReadMask [_StencilReadMask]
            WriteMask [_StencilWriteMask]
        }
        ColorMask [_ColorMask]
        // ...

        Pass
        {
            // ...
            // #### required for RectMask2D ####
            #include "UnityUI.cginc"
            #pragma multi_compile __ UNITY_UI_CLIP_RECT
            float4 _ClipRect;

            // #### required for Mask ####
            #pragma multi_compile __ UNITY_UI_ALPHACLIP

            struct appdata_t
            {
                // ...
            };

            struct v2f
            {
                // ...
                // #### required for RectMask2D ####
                float4 worldPosition    : TEXCOORD1;
            };
            
            v2f vert(appdata_t v)
            {
                v2f OUT;
                // ...
                // #### required for RectMask2D ####
                OUT.worldPosition = v.vertex;
                return OUT;
            }

            fixed4 frag(v2f IN) : SV_Target
            {
                // ...
                // #### required for RectMask2D ####
                #ifdef UNITY_UI_CLIP_RECT
                    color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);
                #endif

                // #### required for Mask ####
                #ifdef UNITY_UI_ALPHACLIP
                    clip (color.a - 0.001);
                #endif

                return color;
            }
            ENDCG
        }
    }
}

Contributing

Issues

Issues are very valuable to this project.

• Ideas are a valuable source of contributions others can make
• Problems show where this project is lacking
• With a question you show where contributors can improve the user experience

Pull Requests

Pull requests are, a great way to get your ideas into this repository.
See CONTRIBUTING.md.

Support

This is an open source project that I am developing in my spare time.
If you like it, please support me.
With your support, I can spend more time on development. :)

License

• MIT

Author

• mob-sakai

See Also

• GitHub page : https://github.com/mob-sakai/ParticleEffectForUGUI
• Releases : https://github.com/mob-sakai/ParticleEffectForUGUI/releases
• Issue tracker : https://github.com/mob-sakai/ParticleEffectForUGUI/issues
• Change log : https://github.com/mob-sakai/ParticleEffectForUGUI/blob/upm/CHANGELOG.md