Shader "DashGame/UIMask"
{
	Properties
	{
		_MainTex("Texture", 2D) = "white" {}
	}

		SubShader
	{
		Tags
	{
		"Queue" = "Transparent"
		"IgnoreProjector" = "True"
		"RenderType" = "Transparent"
		"PreviewType" = "Plane"
		"CanUseSpriteAtlas" = "True"
	}

		Cull Off
		Lighting Off
		ZWrite Off
		ZTest[unity_GUIZTestMode]
		Blend SrcAlpha OneMinusSrcAlpha

		Pass
	{
		CGPROGRAM

#pragma vertex vert
#pragma fragment frag

#include "UnityUI.cginc"
#include "UnityCG.cginc"

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

	struct v2f
	{
		float2 uv : TEXCOORD0;
		float4 color : COLOR;
		float4 vertex : SV_POSITION;
		float4 screenPos : TEXCOORD1;
	};

	sampler2D _MainTex;
	float4 _MainTex_ST;
	float _Angle;
	float _RadiusX;
	float _RadiusY;
	float2 _Center;

	v2f vert(appdata v)
	{
		v2f o;

		o.vertex = UnityObjectToClipPos(v.vertex);
		o.screenPos = ComputeScreenPos(o.vertex);
		o.uv = TRANSFORM_TEX(v.uv, _MainTex);
		o.color = v.color;

		return o;
	}

	fixed4 frag(v2f i) : SV_Target
	{
	//_Center = float2(0.5,0.5);
	_Angle = _RadiusY/4;
	//_RadiusX = 0.2;
	//_RadiusY = 0.2;

		fixed4 col = tex2D(_MainTex, i.uv)*i.color;

		float x = i.screenPos.x - _Center.x;
		float y = i.screenPos.y - _Center.y;

		if (abs(x) < _RadiusX && abs(y) < _RadiusY)
		{
			float2 ulo = _Center + float2(-_RadiusX, _RadiusY);
			float2 uli = ulo + float2(_Angle, -_Angle/(_ScreenParams.y/_ScreenParams.x));

			float2 uro = _Center + float2(_RadiusX, _RadiusY);
			float2 uri = uro + float2(-_Angle, -_Angle / (_ScreenParams.y / _ScreenParams.x));

			float2 lro = _Center + float2(_RadiusX, -_RadiusY);
			float2 lri = lro + float2(-_Angle, _Angle / (_ScreenParams.y / _ScreenParams.x));

			float2 llo = _Center + float2(-_RadiusX, -_RadiusY);
			float2 lli = llo + float2(_Angle, _Angle / (_ScreenParams.y / _ScreenParams.x));

			float urox = uro.x - i.screenPos.x;
			float urix = i.screenPos.x - uri.x;
			float uroy = uro.y - i.screenPos.y;
			float uriy = i.screenPos.y - uri.y;

			float ulox = i.screenPos.x - ulo.x;
			float ulix = uli.x - i.screenPos.x;
			float uloy = ulo.y - i.screenPos.y;
			float uliy = i.screenPos.y - uli.y;

			float lrox = lro.x - i.screenPos.x;
			float lrix = i.screenPos.x - lri.x;
			float lroy = i.screenPos.y - lro.y;
			float lriy = lri.y - i.screenPos.y;

			float llox = i.screenPos.x - llo.x;
			float llix = lli.x - i.screenPos.x;
			float lloy = i.screenPos.y - llo.y;
			float lliy = lli.y - i.screenPos.y;

			if(ulox > 0 && ulix  > 0 && uloy > 0 && uliy > 0)
			{
				float2 vec = uli - i.screenPos;
				vec.y *= _ScreenParams.y / _ScreenParams.x;

				if (length(vec) < _Angle)
				{
					col.a = 0;
				}
			}
			else if(urox > 0 && urix  > 0 && uroy > 0 && uriy > 0)
			{
				float2 vec = uri - i.screenPos;
				vec.y *= _ScreenParams.y / _ScreenParams.x;

				if (length(vec) < _Angle)
				{
					col.a = 0;
				}
			}
			else if (lrox > 0 && lrix > 0 && lroy > 0 && lriy > 0)
			{
				float2 vec = lri - i.screenPos;
				vec.y *= _ScreenParams.y / _ScreenParams.x;

				if (length(vec) < _Angle)
				{
					col.a = 0;
				}
			}
			else if (llox > 0 && llix  > 0 && lloy > 0 && lliy > 0)
			{
				float2 vec = lli - i.screenPos;
				vec.y *= _ScreenParams.y / _ScreenParams.x;

				if (length(vec) < _Angle)
				{
					col.a = 0;
				}
			}
			else
			{
				col.a = 0;
			}
		}

		return col;
	}
		ENDCG
	}
	}
}