Version: 2019.4
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ParticleSystemRenderer.SetActiveVertexStreams

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Declaration

public void SetActiveVertexStreams(List<ParticleSystemVertexStream> streams);

Parameters

streams The new array of enabled vertex streams.

Description

Enables a set of vertex Shader streams on the ParticleSystemRenderer.

using UnityEngine;
using UnityEditor;
using System.Collections.Generic;

public class ExampleClass : MonoBehaviour {

private ParticleSystem ps; private ParticleSystemRenderer psr; private List<Vector4> customData = new List<Vector4>(); public float minDist = 30.0f;

void Start() {

ps = GetComponent<ParticleSystem>(); psr = GetComponent<ParticleSystemRenderer>();

// emit in a sphere with no speed var main = ps.main; main.startSpeedMultiplier = 0.0f; main.simulationSpace = ParticleSystemSimulationSpace.World; // so our particle positions don't require any extra transformation, to compare with the mouse position var emission = ps.emission; emission.rateOverTimeMultiplier = 200.0f; var shape = ps.shape; shape.shapeType = ParticleSystemShapeType.Sphere; shape.radius = 4.0f; psr.sortMode = ParticleSystemSortMode.YoungestInFront;

// send custom data to the shader psr.SetActiveVertexStreams(new List<ParticleSystemVertexStream>(new ParticleSystemVertexStream[] { ParticleSystemVertexStream.Position, ParticleSystemVertexStream.Normal, ParticleSystemVertexStream.Color, ParticleSystemVertexStream.UV, ParticleSystemVertexStream.Custom1X })); }

void Update() {

Camera mainCam = Camera.main;

ps.GetCustomParticleData(customData, ParticleSystemCustomData.Custom1);

// If you know the particle count, or have a reasonable maxParticles threshold, consider caching // this array instead of reallocating it on every frame, to avoid per-frame garbage. int particleCount = ps.particleCount; ParticleSystem.Particle[] particles = new ParticleSystem.Particle[particleCount];

ps.GetParticles(particles);

for (int i = 0; i < particles.Length; i++) { Vector3 sPos = mainCam.WorldToScreenPoint(particles[i].position);

// set custom data to 1, if close enough to the mouse if (Vector2.Distance(sPos, Input.mousePosition) < minDist) { customData[i] = new Vector4(1, 0, 0, 0); } // otherwise, fade the custom data back to 0 else { float particleLife = particles[i].remainingLifetime / ps.main.startLifetimeMultiplier;

if (customData[i].x > 0) { float x = customData[i].x; x = Mathf.Max(x - Time.deltaTime, 0.0f); customData[i] = new Vector4(x, 0, 0, 0); } } }

ps.SetCustomParticleData(customData, ParticleSystemCustomData.Custom1); }

void OnGUI() {

minDist = GUI.HorizontalSlider(new Rect(25, 40, 100, 30), minDist, 0.0f, 100.0f); } }

Here is an example of a custom Shader that you can use with the above script:

          Shader "Particles/CustomVertexStream" {
Properties {
    _TintColor ("Tint Color", Color) = (0.5,0.5,0.5,0.5)
    _MainTex ("Particle Texture", 2D) = "white" {}
    _OffsetValue("Offset Value", Range(0,1)) = 0.4
}

Category { Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" } Blend SrcAlpha OneMinusSrcAlpha ColorMask RGB Cull Off Lighting Off ZWrite Off

SubShader { Pass {

CGPROGRAM #pragma vertex vert #pragma fragment frag #pragma multi_compile_particles #pragma multi_compile_fog

#include "UnityCG.cginc"

sampler2D _MainTex; fixed4 _TintColor; float _OffsetValue;

struct appdata_t { float4 vertex : POSITION; float3 normal : NORMAL; fixed4 color : COLOR; float3 texcoordAndCustom : TEXCOORD0; };

struct v2f { float4 vertex : SV_POSITION; fixed4 color : COLOR; float2 texcoord : TEXCOORD0; float customData : TEXCOORD1; UNITY_FOG_COORDS(2) };

float4 _MainTex_ST;

v2f vert (appdata_t v) { v.vertex.y = lerp(v.vertex.y, v.vertex.y + _OffsetValue, v.texcoordAndCustom.z);

v2f o; o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);

float4 offsetX = float4(-1, 1, 1, -1); float4 offsetY = float4(1, 1, -1, -1);

o.color = v.color; o.texcoord = TRANSFORM_TEX(v.texcoordAndCustom.xy,_MainTex); o.customData = v.texcoordAndCustom.z; UNITY_TRANSFER_FOG(o,o.vertex);

return o; }

fixed4 frag (v2f i) : SV_Target { fixed4 col = 2.0f * i.color * _TintColor * tex2D(_MainTex, i.texcoord); fixed4 col2 = fixed4(i.customData, 0, 0, col.a); fixed4 final = lerp(col, col*col2, i.customData.x);

UNITY_APPLY_FOG(i.fogCoord, final); return final; } ENDCG } } } }