DAY 24
0

• 折射

from wiki

開始撰寫!

``````Shader "Learning/Refraction" {
Properties {
_Color ("Color Tint", Color) = (1, 1, 1, 1)
_RefractColor ("Refraction Color", Color) = (1, 1, 1, 1)
_RefractAmount ("Refraction Amount", Range(0, 1)) = 1
_RefractRatio ("Refraction Ratio", Range(0.1, 1)) = 0.5
_Cubemap ("Refraction Cubemap", Cube) = "_Skybox" {}
}
Tags { "RenderType"="Opaque" "Queue"="Geometry"}

Pass {
Tags { "LightMode"="ForwardBase" }

CGPROGRAM

#pragma multi_compile_fwdbase

#pragma vertex vert
#pragma fragment frag

#include "Lighting.cginc"
#include "AutoLight.cginc"

fixed4 _Color;
fixed4 _RefractColor;
float _RefractAmount;
fixed _RefractRatio;
samplerCUBE _Cubemap;

struct v2f {
float4 pos : SV_POSITION;
float3 worldPos : TEXCOORD0;
fixed3 worldNormal : TEXCOORD1;
fixed3 worldViewDir : TEXCOORD2;
fixed3 worldRefr : TEXCOORD3;
};

v2f vert(appdata_base v) {
v2f o;
o.pos = UnityObjectToClipPos(v.vertex);

o.worldNormal = UnityObjectToWorldNormal(v.normal);

o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;

o.worldViewDir = UnityWorldSpaceViewDir(o.worldPos);

// 利用入射角與入射平面的法向量，以及「折射率」
o.worldRefr = refract(-normalize(o.worldViewDir), normalize(o.worldNormal), _RefractRatio);

return o;
}

fixed4 frag(v2f i) : SV_Target {
fixed3 worldNormal = normalize(i.worldNormal);
fixed3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));
fixed3 worldViewDir = normalize(i.worldViewDir);

fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;

fixed3 diffuse = _LightColor0.rgb * _Color.rgb * max(0, dot(worldNormal, worldLightDir));

fixed3 refraction = texCUBE(_Cubemap, i.worldRefr).rgb * _RefractColor.rgb;

UNITY_LIGHT_ATTENUATION(atten, i, i.worldPos);

fixed3 color = ambient + lerp(diffuse, refraction, _RefractAmount) * atten;

return fixed4(color, 1.0);
}

ENDCG
}
}
}

``````