参照【风宇冲】Unity3D教程宝典之Shader篇：第四讲制作一个美丽的地球和Unity3D教程宝典之Shader篇：第五讲LOGO闪光效果
这两篇文章都是引入时间这一因素，进行shader的移动达到的效果
一、【风宇冲】Unity3D教程宝典之Shader篇：第四讲制作一个美丽的地球
Shader "Custom/earth" {
Properties {
_MainTex ("Texture", 2D) = "white" { }
_Cloud ("_Cloud", 2D) = "white" { }
}
SubShader {
Tags{"Queue" = "Transparent" "RenderType"="Transparent"}
Pass {
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
float4 _Color;
sampler2D _MainTex;
sampler2D _Cloud;
struct v2f {
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
} ;
float4 _MainTex_ST;
v2f vert (appdata_base v)
{
//和之前一样
v2f o;
o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
o.uv = TRANSFORM_TEX (v.texcoord, _MainTex);
return o;
}
half4 frag (v2f i) : COLOR
{
//地球的贴图uv, x即横向在动
float u_x = i.uv.x + -0.1*_Time;
float2 uv_earth=float2( u_x , i.uv.y);
half4 texcolor_earth = tex2D (_MainTex, uv_earth);
//云层的贴图uv的x也在动，但是动的更快一些
float2 uv_cloud;
u_x = i.uv.x + -0.2*_Time;
uv_cloud=float2( u_x , i.uv.y);
half4 tex_cloudDepth = tex2D (_Cloud, uv_cloud);
//纯白 x 深度值= 该点的云颜色
half4 texcolor_cloud = float4(1,1,1,0) * (tex_cloudDepth.x);
//地球云彩颜色混合
return lerp(texcolor_earth,texcolor_cloud,0.5f);
}
ENDCG}}}
二、Unity3D教程宝典之Shader篇：第五讲LOGO闪光效果
Shader "Custom/logo" {
Properties {
//_Color ("Color", Color) = (1,1,1,1)
_MainTex ("Albedo (RGB)", 2D) = "white" {}
//_Glossiness ("Smoothness", Range(0,1)) = 0.5
//_Metallic ("Metallic", Range(0,1)) = 0.0
}
SubShader {
Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
Blend SrcAlpha OneMinusSrcAlpha
AlphaTest Greater 0.1
pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
sampler2D _MainTex;
float4 _MainTex_ST;
struct v2f {
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
};
//顶点函数没什么特别的，和常规一样
v2f vert (appdata_base v)
{
v2f o;
o.pos = mul(UNITY_MATRIX_MVP,v.vertex);
o.uv = TRANSFORM_TEX(v.texcoord,_MainTex);
return o;
}
//必须放在使用其的 frag函数之前，否则无法识别。
//核心：计算函数，角度，uv,光带的x长度，间隔，开始时间，偏移，单次循环时间
float inFlash(float angle,float2 uv,float xLength,int interval,int beginTime, float offX, float loopTime )
{
//亮度值
float brightness =0;
//倾斜角
float angleInRad = 0.0174444 * angle;
//当前时间
float currentTime = _Time.y;
//获取本次光照的起始时间
int currentTimeInt = _Time.y/interval;
currentTimeInt *=interval;
//获取本次光照的流逝时间 = 当前时间 - 起始时间
float currentTimePassed = currentTime -currentTimeInt;
if(currentTimePassed >beginTime)
{
//底部左边界和右边界
float xBottomLeftBound;
float xBottomRightBound;
//此点边界
float xPointLeftBound;
float xPointRightBound;
float x0 = currentTimePassed-beginTime;
x0 /= loopTime;
//设置右边界
xBottomRightBound = x0;
//设置左边界
xBottomLeftBound = x0 - xLength;
//投影至x的长度 = y/ tan(angle)
float xProjL;
xProjL= (uv.y)/tan(angleInRad);
//此点的左边界 = 底部左边界 - 投影至x的长度
xPointLeftBound = xBottomLeftBound - xProjL;
//此点的右边界 = 底部右边界 - 投影至x的长度
xPointRightBound = xBottomRightBound - xProjL;
//边界加上一个偏移
xPointLeftBound += offX;
xPointRightBound += offX;
//如果该点在区域内
if(uv.x > xPointLeftBound && uv.x < xPointRightBound)
{
//得到发光区域的中心点
float midness = (xPointLeftBound + xPointRightBound)/2;
//趋近中心点的程度，0表示位于边缘，1表示位于中心点
float rate= (xLength -2*abs(uv.x - midness))/ (xLength);
brightness = rate;
}
}
brightness= max(brightness,0);
//返回颜色 = 纯白色 * 亮度
float4 col = float4(1,1,1,1) *brightness;
return brightness;
}
float4 frag (v2f i) : COLOR
{
float4 outp;
//根据uv取得纹理颜色，和常规一样
float4 texCol = tex2D(_MainTex,i.uv);
//传进i.uv等参数，得到亮度值
float tmpBrightness;
tmpBrightness =inFlash(75,i.uv,0.25,5,2,0.15,0.7);
//图像区域，判定设置为 颜色的A > 0.5,输出为材质颜色+光亮值
if(texCol.w >0.5)
outp =texCol+float4(1,1,1,1)*tmpBrightness;
//空白区域，判定设置为 颜色的A <=0.5,输出空白
else
outp =float4(0,0,0,0);
return outp;
}
ENDCG
}
}
}
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