unity shader水波源码

// Upgrade NOTE: replaced '_Object2World' with 'unity_ObjectToWorld'        

Shader "ylq/Water Wave" {
	Properties {
		_Color ("Main Color", Color) = (0, 0.15, 0.115, 1)//物体原本的颜色
		_MainTex ("Base (RGB)", 2D) = "white" {}//主纹理
		_WaveMap ("Wave Map", 2D) = "bump" {}//波动纹理
		_Cubemap ("Environment Cubemap", Cube) = "_Skybox" {}//环境纹理
		_WaveXSpeed ("Wave Horizontal Speed", Range(-0.1, 0.1)) = 0.01//水平波动速读
		_WaveYSpeed ("Wave Vertical Speed", Range(-0.1, 0.1)) = 0.01//竖直波动速读
		_Distortion ("Distortion", Range(0, 100)) = 10//
		_DistanceFactor("DistanceFactor",Float)=1//距离因子
		_TimeFactor("TimeFactor",Float)=1//时间因子
		_MaxOffSet("MaxOffSet",Float)=1//主纹理偏移因子
		_WaveWidth("WaveWidth",Float)=0//波宽
		_WaveAmount("WaveAmount",Float)=1//波数
		_WavePoint("WavePoint",Color)=(0,0,0,0)//波点
	}
	SubShader {
		Tags { "Queue"="Transparent" "RenderType"="Opaque" }//物体类型  渲染队列
		
		GrabPass { "_RefractionTex" }
		
		Pass {
			Tags { "LightMode"="ForwardBase" }//参照灯光类型
			Blend SrcAlpha OneMinusSrcAlpha
			CGPROGRAM//开始CGprogram

			
			#include "UnityCG.cginc"//引用，可以使用内置函数
			#include "Lighting.cginc"//引用，使用灯光内置
			
			#pragma multi_compile_fwdbase
			
			#pragma vertex vert//顶点函数声明
			#pragma fragment frag//片元函数说明
			
			fixed4 _Color;//对要使用的属性重新声明
			sampler2D _MainTex;
			float4 _MainTex_ST;
			sampler2D _WaveMap;
			float4 _WaveMap_ST;
			samplerCUBE _Cubemap;
			fixed _WaveXSpeed;
			fixed _WaveYSpeed;
			float _Distortion;	
			sampler2D _RefractionTex;
			float4 _RefractionTex_TexelSize;
			fixed _DistanceFactor;
			fixed _TimeFactor;
			fixed _MaxOffSet;
			fixed _WaveAmount;
			fixed _WaveWidth;
			fixed4 _WavePoint;

			struct a2v {                               //结构体 application  to  vertex
				float4 vertex : POSITION;//顶点
				float3 normal : NORMAL;//法线
				float4 tangent : TANGENT; //切线 正切
				float4 texcoord : TEXCOORD0;//纹理
			};
			
			struct v2f {                                   //vertex to   fragment

				float4 pos : SV_POSITION;//位置     
				float4 scrPos : TEXCOORD0;//屏幕位置
				float4 uv : TEXCOORD1;//
				float4 TtoW0 : TEXCOORD2;  //
				float4 TtoW1 : TEXCOORD3;  //
				float4 TtoW2 : TEXCOORD4; //
			};
			
			v2f vert(a2v v) {								//顶点函数 传入顶点
				v2f o;
				o.pos = mul(UNITY_MATRIX_MVP, v.vertex);//模型空间转换到剪裁空间
				
				o.scrPos = ComputeGrabScreenPos(o.pos);//将模型从剪裁空间转换到屏幕空间
				
				o.uv.xy = TRANSFORM_TEX(v.texcoord, _MainTex);//获取主纹理屏幕的xy
				o.uv.zw = TRANSFORM_TEX(v.texcoord, _WaveMap);//获取波纹理屏幕的xy
				
				float3 worldPos = mul(_Object2World, v.vertex).xyz;  //模型空间转换到世界空间
				fixed3 worldNormal = UnityObjectToWorldNormal(v.normal);  //将法线从模型空间转换到世界空间
				fixed3 worldTangent = UnityObjectToWorldDir(v.tangent.xyz);  //将切线从模型空间转换到世界空间
				fixed3 worldBinormal = cross(worldNormal, worldTangent) * v.tangent.w; //叉乘（法线，正切）
				
				o.TtoW0 = float4(worldTangent.x, worldBinormal.x, worldNormal.x, worldPos.x);  
				o.TtoW1 = float4(worldTangent.y, worldBinormal.y, worldNormal.y, worldPos.y);  
				o.TtoW2 = float4(worldTangent.z, worldBinormal.z, worldNormal.z, worldPos.z);  
				
				return o;
			}
			
			fixed4 frag(v2f i) : SV_Target //为什么要用矩阵，因为c#控制纹理缩放，偏移，旋转，要比shader慢
			{
				float3 worldPos = float3(i.TtoW0.w, i.TtoW1.w, i.TtoW2.w);
				fixed3 viewDir = normalize(UnityWorldSpaceViewDir(worldPos));//
				float2 speed = _Time.y * float2(_WaveXSpeed, _WaveYSpeed);//二维向量的波速
				
				fixed3 bump1 = UnpackNormal(tex2D(_WaveMap, i.uv.zw + speed)).rgb;//纹理波速
				fixed3 bump2 = UnpackNormal(tex2D(_WaveMap, i.uv.zw - speed)).rgb;
				fixed3 bump = normalize(bump1 + bump2);//叠加
				
				float2 offset = bump.xy * _Distortion * _RefractionTex_TexelSize.xy;//获取偏移
				i.scrPos.xy = offset * i.scrPos.z + i.scrPos.xy;//使得定点的位置，变换到偏移之后的位置
				fixed3 refrCol = tex2D( _RefractionTex, i.scrPos.xy/i.scrPos.w).rgb;
				
				bump = normalize(half3(dot(i.TtoW0.xyz, bump), dot(i.TtoW1.xyz, bump), dot(i.TtoW2.xyz, bump)));
				fixed4 texColor = tex2D(_MainTex, i.uv.xy + speed);
				fixed3 reflDir = reflect(-viewDir, bump);
				fixed3 reflCol = texCUBE(_Cubemap, reflDir).rgb * texColor.rgb * _Color.rgb;
				
				fixed fresnel = pow(1 - saturate(dot(viewDir, bump)), 4);
				fixed3 finalColor = reflCol * fresnel + refrCol * (1 - fresnel);
				
				float2 dir = _WavePoint.xy - i.uv.xy;
				float dis = length(dir);
				float2 offset1 = normalize(dir)*sin(dis*_DistanceFactor + _Time.y*_TimeFactor)*_MaxOffSet*0.1;
				float t1 = smoothstep(0, 1, _WaveWidth - dis);
				float t2 = 1 - t1;
				float4 offcol = tex2D(_MainTex,i.uv.xy+offset1);//主纹理偏移

				return lerp(fixed4(finalColor,t2)*_Color,fixed4(offcol.rgb,t1),t1*_WaveAmount);//lerp为什么三个参数？？
			}
			
			ENDCG//结束CG
		}
	}
	// Do not cast shadow
	FallBack Off
}