修仙笔记Shader篇之着色器变体以及实现UV流动Shader

本帖最后由 SmilingFace 于 2023-4-18 20:24 编辑

Shader "multi_comple"
{
    Properties
    {
        _MainTex ("MainTex", 2D) = "white" {}

        _Noise ("Noise", 2D) = "white" {}

        _Color ("Color",Color) = (1.0,1.0,1.0,1.0)
        //控制渐变区域以及硬度
        _GradientTill ("GradientTill",float) = 1
        _GradientOffset("GradientOffset",float) = 0

        _timeSpeed("timeSpeed",float) = 1
        //变体开关
        [Toggle]_FLOWEnable("FLOW Enable",int) = 0

    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }


        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            //变体，请注意_FLOWENABLE，要与属性设置中的名称 一致，并且需要全大写
            #pragma multi_compile _ _FLOWENABLE_ON


            #include "UnityCG.cginc"

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

            struct v2f
            {
                float4 uv : TEXCOORD0;

                float4 vertex : SV_POSITION;
                float3 worldPos:TEXCOORD1;
                float3 relativePos:TEXCOORD2;
            };

            sampler2D _MainTex;
            sampler2D _Noise;
            float4 _Noise_ST;
            float4 _Color;
            float _GradientTill;
            float _GradientOffset;
            float _timeSpeed;


            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv.xy =v.texcoord;
                o.uv.zw = v.texcoord* _Noise_ST.zw+  _Noise_ST.xy;
                o.worldPos = mul(unity_ObjectToWorld,v.vertex);
                o.relativePos = mul(unity_ObjectToWorld,(v.vertex-float3(0.0,0.0,0.0)));
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                float2 uv1 = i.uv.xy;
                float2 uv2 = i.uv.zw;
                //通过开关变体，实现uv流动
                #if _FLOWENABLE_ON
                    uv2 = i.uv.zw-float2(0.5,_Time.y)*_timeSpeed;
              //此处最好加一个Fract函数钳制uv的大小，否则运行时间长了，可能会出现uv数值大于Float允许的精度范围，导致出问题。
                #endif
                float3 worldPos = i.worldPos;
                float3 relativePos = i.relativePos;
                half baseColor = tex2D(_MainTex, uv1);
                half noise = tex2D(_Noise,uv2);
                half gradient = relativePos.y*_GradientTill+_GradientOffset;
                gradient = saturate(1-gradient);
                half3 finalColor = _Color*noise*gradient+baseColor;

                return half4(finalColor,1.0);

            }
            ENDCG
        }
    }
}

那个relativePos不是很理解