How many particles ?

News & General Discussion
1

Hi every one
What the secret in this vdeo?
(no compute shader no geometry shsader) just pixel and vertex shader

2

GPU particles should be able to do that.
Perhaps even with normal cpu particles you can reach similar number of particles if that is all you’re rendering. I haven’t tried though so I might be wrong.

3

Looks like trail/line renderers.

4

Ah, yes! Now that you said it that definitely looks like dotted texture and trails instead of particles.

5

Yes,You are right.
Take your gift

using UnityEngine;
using System.Collections;

public class FO : MonoBehaviour {

	// Use this for initialization
	Transform my;
	public float t1, t2,S,r1,r2;
	float tt,ttt;
	Vector3 dir,OLD;
	void Start () {
		my = GetComponent<Transform>();
		tt = Random.Range(t1, t2);
		ttt = tt;
		OLD = my.localPosition;
		dir = Random.onUnitSphere * Random.Range(r1, r2); ;
	}
	
	// Update is called once per frame
	void Update () {
		my.localPosition = Vector3.Slerp(dir, OLD, tt / ttt);
		tt -= S*Time.deltaTime;
		if (tt < 0.0f)
		{
			ttt=tt = Random.Range(t1, t2);
			OLD = my.localPosition;
			dir = Random.onUnitSphere * Random.Range(r1, r2); ;
		}
	}
}

And the shader

Shader "Games/Circle2" {
	Properties {
		c1 ("r b", Color) = (1,0,0,1)
		c2 ("r e", Color) = (0,1,0,1)
		c3 ("a b", Color) = (0,0,1,1)
		c4 ("a e", Color) = (1,1,0,1)
		cn ("number of circle", Float) = 24
	}
	SubShader {
		Pass {
			Blend One zero
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#pragma debug
			#pragma only_renderers d3d11 
			#pragma target  5.0
			#include "UnityCG.cginc"
			float4 c1,c2,c3,c4;
			float cn;
			struct v2f {
				float4  pos : SV_POSITION;
				float2  uv : TEXCOORD0;
			};


			v2f vert (appdata_base v)
			{
				v2f o;
				o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
				o.uv = v.texcoord.xy;
				return o;
			}

			half4 frag (v2f i) : COLOR
			{
				float x=i.uv.x;
				i.uv.x=frac(i.uv.x*cn);
				i.uv-=float2(0.5f,0.5f);
				float b=dot(i.uv,i.uv)*4.0f;
				if(b<=x)
					return lerp(c1,c2,b)+lerp(c3,c4,x);
				else
					discard;
				return (float4)0;
			}
			ENDCG
		}
	}
	Fallback "VertexLit"
}
6

7 particles.

1 Like
7

How did you count them?

8

For mobile, this is incredibly slow, possibly unusable vs just having a particle system with fastest possible shader.

9

I was thinking perhaps it was just pulling vertex coords from a texture which had totally precalculated paths for particles to follow, because although the camera was moving it didn’t seem like the particles were really moving.

You can make gpu-driven particle systems without compute shaders or dx11… you can get millions of particles just using rendertextures and reading/writing vertex coordinates in a shader.