Unity菜鸟开发纪要——鱼眼Shader

// 鱼眼效果,计算公式网上找的
Shader "UI-Effect/FishEye"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _Factor_x ("x轴方向畸变", Range(0, 0.15)) = 0
        _Factor_y("y 轴方向畸变", Range(0, 0.15)) = 0
        _Scale("畸变范围", Float) = 1
        [Toggle] _UseTex("使用原始贴图", Int) = 0
    }
    SubShader
    {
        // No culling or depth
        Cull Off ZWrite Off ZTest Always

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // shader_feature 可能在真机上会失效
            #pragma multi_compile _USETEX_ON

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                return o;
            }


            sampler2D _MainTex;
            float _Factor_x;
            float _Factor_y;
            float _Scale;

            inline fixed2 CalEyeUV(fixed2 uv)
            {
                float2 uv0 = (uv - 0.5) * 2.0; 
                float2 uv1;
                uv1.x = (1 - uv0.y * uv0.y) * _Factor_y * (uv0.x);	
                uv1.y = (1 - uv0.x * uv0.x) * _Factor_x * (uv0.y);	
                return(uv - uv1);
            }


            fixed4 frag (v2f i) : SV_Target
            {
                #if _USETEX_ON 
                    float2 eyeUV = CalEyeUV(i.uv);
                    fixed4 col = tex2D(_MainTex, eyeUV);
                #else
                    fixed4 col = tex2D(_MainTex, i.uv);
                #endif
                return col;
            }
            ENDCG
        }
    }
}