koten-PenTransparent.shader

// Reference: https://qiita.com/ShirakawaMaru/items/e29d95e86add4ec0e3b7

Shader "Custom/PenTransparent" {
    SubShader {
        Pass {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma target 3.0

            struct v2f {
                float2 uv : TEXCOORD0;
            };

            v2f vert(float4 pos : POSITION, out float4 wpos : SV_POSITION, float2 uv : TEXCOORD0) {
                v2f o;
                o.uv = uv;
                wpos = UnityObjectToClipPos(pos);
                return o;
            }

            float4 frag(v2f i , UNITY_VPOS_TYPE vpos : VPOS) : SV_TARGET {
                float4 col = {1, 1, 1, 1};
                int2 xy = vpos.xy / _ScreenParams.x * 100;
                col.rgb = ((xy.x+xy.y)&1) ? 1 : ((float) 0xCC / 0xFF);
                return col;
            }

            ENDCG
        }
    }
}