quill.shader

// https://forums.oculusvr.com/community/discussion/57052/quill-fbx-to-unity3d#latest

Shader "Unlit/Quill Shader" {

	Properties {
		_MainTex ("Texture", 2D) = "white" {}
	}

	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;
				float4 col:COLOR;
			};

			struct v2f {
				float2 uv : TEXCOORD0;
				UNITY_FOG_COORDS(1)
				float4 vertex : SV_POSITION;
				float4 col:COLOR;
				float4 screenPos : TEXCOORD1;
			};

			sampler2D _MainTex;
			float4 _MainTex_ST;

			v2f vert (appdata v) {
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.uv = TRANSFORM_TEX(v.uv, _MainTex);
				o.col = v.col;
				o.screenPos = ComputeScreenPos(o.vertex);
				UNITY_TRANSFER_FOG(o,o.vertex); 
				return o;
			}

			fixed4 frag (v2f i) : SV_Target {
				// sample the texture
				fixed4 col = i.col; //tex2D(_MainTex, i.uv);

				// Screen-door transparency: Discard pixel if below threshold. 
				float4x4 thresholdMatrix = 
				{ 1.0 / 17.0, 9.0 / 17.0, 3.0 / 17.0, 11.0 / 17.0, 
				13.0 / 17.0, 5.0 / 17.0, 15.0 / 17.0, 7.0 / 17.0, 
				4.0 / 17.0, 12.0 / 17.0, 2.0 / 17.0, 10.0 / 17.0, 
				16.0 / 17.0, 8.0 / 17.0, 14.0 / 17.0, 6.0 / 17.0
				}; 
				float4x4 _RowAccess = { 1,0,0,0, 0,1,0,0, 0,0,1,0, 0,0,0,1 }; 
				float2 pos = i.screenPos.xy / i.screenPos.w; 
				pos *= _ScreenParams.xy; // pixel position 
				//pos.x += (fmod(pos.x, 6)<1)*1;
				//pos.x *= 1.1;
				clip(i.col.a - thresholdMatrix[fmod(pos.x, 4)] * _RowAccess[fmod(pos.y, 4)]); 

				// apply fog
				UNITY_APPLY_FOG(i.fogCoord, col);
				return col;
			}
			ENDCG
		}
	}

}