[Unity] UnityのShaderでステンシルバッファを試す ref: http://qiita.com/edo_m18/items/95a7f350d1164486e03b

stencile-sample

Shader "Red" {
    SubShader {
        Tags { "RenderType"="Opaque" "Queue"="Geometry"}
        Pass {
            Stencil {
                Ref 2
                Comp always
                Pass replace
                ZFail decrWrap
            }

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            struct appdata {
                float4 vertex : POSITION;
            };
            struct v2f {
                float4 pos : SV_POSITION;
            };
            v2f vert(appdata v) {
                v2f o;
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                return o;
            }
            half4 frag(v2f i) : COLOR {
                return half4(1,0,0,1);
            }
            ENDCG
        }
    } 
}

stencile-snipet

Stencil {
    Ref 2
    Comp always
    Pass replace
    ZFail decrWrap
}

syntax-stencil

Ref [整数値]
Comp [比較関数]
Pass [合格]
Fail [不合格]
ZFail [合格だが深度テスト不合格]