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@rngtm
Created June 27, 2017 15:27
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正N角形の線が描けるシェーダー
Shader "Unlit/PolygonLine"
{
Properties
{
[HideInInspector] _MainTex ("Texture", 2D) = "white" {}
_N("N", Int) = 3
_W("Width", Range(0, 1.0)) = 0.1
}
SubShader
{
Tags { "RenderType"="Opaque" }
LOD 100
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
// make fog work
#pragma multi_compile_fog
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
UNITY_FOG_COORDS(1)
float4 vertex : SV_POSITION;
};
sampler2D _MainTex;
float4 _MainTex_ST;
v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
UNITY_TRANSFER_FOG(o,o.vertex);
return o;
}
#define PI 3.14159265358979
#define R 0.5 // 多角形の大きさ
int _N;
float _W; // 線の太さ
fixed4 frag (v2f i) : SV_Target
{
float2 uv = i.uv - 0.5;
float r = length(uv); // 原点からの距離
float theta = atan2(uv.x, uv.y) + 2.0 * PI; // 原点からの角度 (負にならないように2π足しています)
theta = theta % (2.0 * PI / _N); // 角度の補正
float r2 = cos(PI / _N) / cos (PI / _N - theta); // 中心から多角形までの距離
return step(r2 * R * (1.0 - _W), r) * step(r, r2 * R);
}
ENDCG
}
}
}
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