在虚线着色器上添加​​边框需要帮助

Question

我在 Unity 中有一个用于虚线着色器的脚本，例如 that example

问题是我想在每个圆圈周围制作一个黑色边框，而且我是使用着色器的新手。任何人都可以帮助我或教我吗？这是脚本，以防有人需要：

Shader "Unlit/DottedLineShader"
{
    Properties
    {
        _RepeatCount("Repeat Count", float) = 5
        _Spacing("Spacing", float) = 0.5
        _Offset("Offset", float) = 0
    }
    SubShader
    {
        Tags{ "RenderType" = "Transparent" "Queue" = "Transparent" }
        LOD 100

        Blend SrcAlpha OneMinusSrcAlpha
        ZWrite Off

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            float _RepeatCount;
            float _Spacing;
            float _Offset;

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
                fixed4 color : COLOR0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
                fixed4 color : COLOR0;
            };

            v2f vert(appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                o.uv.x = (o.uv.x + _Offset) * _RepeatCount * (1.0f + _Spacing);
                o.color = v.color;

                return o;
            }

            fixed4 frag(v2f i) : SV_Target
            {
                i.uv.x = fmod(i.uv.x, 1.0f + _Spacing);
                float r = length(i.uv - float2(1.0f + _Spacing, 1.0f) * 0.5f) * 2.0f;

                fixed4 color = i.color;
                color.a *= saturate((0.99f - r) * 100.0f);

                return color;
            }
        ENDCG
        }
    }
}

Answer 1

您可以使用内置的 smoothstep 函数来“剪裁”半径 (r) 的一部分并创建像素完美、抗锯齿的边框；

// Values below must be between 0-1
float borderRadius = 0.5;
float borderSmoothness = 0.1;    

color.rgb *= smoothstep(borderRadius - borderSmoothness, borderRadius, 1.0 - r);