用到了一个新的PASS:GrabPass.效果图如下:
因为是先截取屏幕后,进行一个混合运算,黄色方块虽然在plane的前方,但还是会有扭曲的效果.如果要实现清澈河流的效果.可能还是用Render Texture 更加的合适.也更节省性能.
切线空间转换这里现在还不是很懂.当前只是把代码扒下来.有空回头再看几遍空间转换.
Shader"wx/Glass"{
Properties{
_MainTex("Main Tex",2D)="white"{}
_BumpMap("Normal Map",2D)="bump"{}
_CubeMap("Environment Cubemap",Cube)="_Skybox"{}
_Distortion("Distortion",Range(0,100))=10
_RefractAmount("Refract Amount",Range(0,1.0))=1.0
}
SubShader{
Tags{"Queue"="Transparent" "RenderType"="Opaque"}
GrabPass{"_RefractionTex"}
Pass{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
sampler2D _MainTex;
float4 _MainTex_ST;
sampler2D _BumpMap;
float4 _BumpMap_ST;
samplerCUBE _Cubemap;
float _Distortion;
fixed _RefractAmount;
sampler2D _RefractionTex;
float4 _RefractionTex_TexelSize;
struct a2v
{
float4 vertex:POSITION;
float3 normal:NORMAL;
float4 texcoord:TEXCOORD0;
float4 tangent:TANGENT;
};
struct v2f
{
float4 pos:SV_POSITION;
float4 scrPos:TEXCOORD0;
float4 uv:TEXCOORD1;
float4 TtoW0:TEXCOORD2;
float4 TtoW1:TEXCOORD3;
float4 TtoW2:TEXCOORD4;
};
v2f vert(a2v v){
v2f o;
o.pos=UnityObjectToClipPos(v.vertex);
o.scrPos=ComputeGrabScreenPos(o.pos);
o.uv.xy=TRANSFORM_TEX(v.texcoord,_MainTex);
o.uv.zw=TRANSFORM_TEX(v.texcoord,_BumpMap);
float3 worldPos=mul(unity_ObjectToWorld,v.vertex).xyz;
fixed3 worldNormal=UnityObjectToWorldNormal(v.normal);
fixed3 worldTangent=UnityObjectToWorldDir(v.tangent.xyz);
fixed3 worldBinormal=cross(worldNormal,worldTangent)*v.tangent.w;
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{
float3 worldPos=float3(i.TtoW0.x,i.TtoW1.x,i.TtoW2.x);
fixed3 worldViewDir=normalize(UnityWorldSpaceViewDir(worldPos));
fixed3 bump=UnpackNormal(tex2D(_BumpMap,i.uv.zw));
float2 offset=bump.xy*_Distortion*_RefractionTex_TexelSize.xy;
i.scrPos.xy=offset+i.scrPos.xy;
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)));
fixed3 reflDir=reflect(-worldViewDir,bump);
fixed4 texColor=tex2D(_MainTex,i.uv.xy);
fixed3 reflCol=texCUBE(_Cubemap,reflDir).rgb*texColor.rgb;
fixed3 finalColor=reflCol*(1-_RefractAmount)+refrCol*_RefractAmount;
return fixed4(finalColor,1);
}
ENDCG
}
}
}