所谓流光效果，如一个图片上一条刀光从左闪到右边，以下为实现代码：
c#代码：
using System;
using UnityEngine; public class WalkLightEffect : MonoBehaviour
{
public Texture MainTex;
public Texture LightTex;
public float Duration;
public float LightULen;
public Vector2 Size; bool m_play;
float m_timer;
float m_t1; void Awake()
{
if (MainTex == null)
throw new ArgumentNullException("MainTex");
if (LightTex == null)
throw new ArgumentNullException("LightTex");
if (Duration <= )
throw new ArgumentException("Duration");
if (LightULen <= || LightULen >= )
throw new ArgumentException("LightULen <= 0 || LightULen >= 1");
if (Size.x <= || Size.y <= )
throw new ArgumentException("Size.x <= 0 || Size.y <= 0"); GenerateRenderer(); m_t1 = ( - LightULen) * Duration;
} void GenerateRenderer()
{
// Mesh
Mesh mesh = new Mesh();
mesh.vertices = new Vector3[]
{
new Vector2(-Size.x/,Size.y/),
new Vector2(Size.x/,Size.y/),
new Vector2(-Size.x/,-Size.y/),
new Vector2(Size.x/,-Size.y/),
};
mesh.triangles = new int[] { , , , , , };
mesh.uv = new Vector2[]
{
new Vector2(,),
new Vector2(,),
new Vector2(,),
new Vector2(,),
}; mesh.Optimize(); var mf = gameObject.AddComponent<MeshFilter>();
mf.mesh = mesh; // Material
var mat = new Material(Shader.Find("Bleach/WalkLight"));
mat.SetTexture("_MainTex", MainTex);
mat.SetFloat("_LightLen", LightULen); var mr = gameObject.AddComponent<MeshRenderer>();
mr.sharedMaterial = mat;
} void Update()
{
if (m_play)
{
renderer.material.SetFloat("_TimeRate", m_timer / Duration); m_timer += Time.deltaTime; if (m_timer > Duration)
m_timer = ;
else if (m_timer > m_t1)
renderer.material.SetFloat("_ReachBoundary", );
else
renderer.material.SetFloat("_ReachBoundary", -);
}
} public bool Play
{
set
{
renderer.material.SetTexture("_LightTex", value ? LightTex : null);
m_timer = ;
m_play = value;
}
}
}
shader代码：
Shader "Bleach/WalkLight"
{
Properties
{
_MainTex ("Main", 2D) = "white" {}
_LightTex("Light", 2D) = "black" {}
_LightLen("Light Length", float) =
} SubShader
{
Pass
{
Tags { "RenderType"="Opaque" }
LOD Cull Off CGPROGRAM
#pragma vertex vert
#pragma fragment frag uniform sampler2D _MainTex;
uniform sampler2D _LightTex;
uniform fixed _LightLen; uniform fixed _ReachBoundary; // 小于0表示未到边界，大于0表示到达边界
uniform fixed _TimeRate; // 时间/周期 struct Data
{
fixed4 vertex:POSITION;
fixed2 texcoord:TEXCOORD0;
}; struct V2F
{
fixed4 pos:SV_POSITION;
fixed2 uv:TEXCOORD0;
}; V2F vert(Data v)
{
V2F o;
o.pos=mul(UNITY_MATRIX_MVP,v.vertex);
o.uv=v.texcoord;
return o;
} fixed4 frag(V2F i):COLOR
{
fixed4 main = tex2D(_MainTex,i.uv);
fixed x = _ReachBoundary> && i.uv.x<_LightLen? i.uv.x+ : i.uv.x;
fixed lightU = (x - _TimeRate)/_LightLen; // u=(x-timer/Duration)/_LightLen;
fixed4 light = tex2D(_LightTex,float2(lightU,i.uv.y)); return lerp(main,light,light.a);
} ENDCG
}
} FallBack "Diffuse"
}