// Upgrade NOTE: replaced '_Object2World' with 'unity_ObjectToWorld'

Shader "Custom/AdditiveScreenTexture"{
Properties {
	_TintColor ("Tint Color", Color) = (1,1,1,1)
	_EmissionGain ("Emission Gain", Range(0, 1)) = 0.052
	_Cloudy ("Cloudy", Range (0, 4)) = .15
	_Params ("Size (MinMax) Wind (MinMax)", Vector) = (32, 64, 1, 1)
	_ParamsB ("Angle (RAD) Variat", Vector) = (-1.87, -1.27, 5, 0)
	_Wind ("Wind speed", Range (0, 2)) = .2
	_Rotation ("Rotation", Range (0, 1)) = 0
	_Samples ("Samples", Range (1, 10)) = 2
	_MainTex ("Texture", 2D) = "white" {}

}

Category {
	Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
	Blend SrcAlpha One
	ZWrite Off

	SubShader {
		Pass {

			CGPROGRAM
// Upgrade NOTE: excluded shader from DX11; has structs without semantics (struct v2f members worldPos)
#pragma exclude_renderers d3d11
			#pragma vertex vert
			#pragma fragment frag

			fixed4 _TintColor;
			float _EmissionGain;
			half _Cloudy;
			half _Rotation;
			half _Wind;
			half4 _Params;
			half4 _ParamsB;
			int _Samples;
			sampler2D _MainTex;
            float4 _MainTex_ST;

			struct appdata_t {
				float4 vertex : POSITION;
				fixed4 color : COLOR;
			};

			struct v2f {
				float4 vertex : SV_POSITION;
				fixed4 color : COLOR;
				float2 worldPosition: TEXCOORD0;
			};


			v2f vert (appdata_t v)
			{
				v2f o;
				o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
				o.color = v.color ;
				o.worldPosition = mul(unity_ObjectToWorld, v.vertex);
				return o;
			}

			float pingpong(float value, float freq){
				return sin( (value*3.1415926536) * freq);
			}

			float semiRandom(float2 uv){
				return frac(sin(dot(uv, float2(12.9898, 78.233))) * 43758.5453);
			}

			fixed noise(v2f i, float size, float2 speed){
				float2 uv = speed * _Time.x + i.worldPosition.xy * size;
				return tex2D(_MainTex, uv).x;
			}


			// rotated 45 degrees
			fixed noise45(v2f i, float size, float2 speed){
				float2 uv = speed * _Time.x + i.worldPosition.xy * size;

				float y = uv.y * 0.7071067812;
				float x = uv.x * 0.7071067812;
				uv = half2(x+y,-x+y);

				return tex2D(_MainTex, uv).x;
			}

			fixed noise452(v2f i, float size, float2 speed) {
                float2 xy = speed * _Time.x + i.worldPosition.xy * size;

				// xy = xy * 0.7071067812;
				// xy = float2(xy.x+xy.y,-xy.x+xy.y);
                xy = tex2D(_MainTex, xy).xy ;

                return abs(xy.x + sin(( (xy.x * 1.3f + xy.y * 2.135f) - (xy.x * 1.172f + xy.y * .35f)) * _ParamsB.z * _Time.x) * 0.6f);
            }

			float2 rotate(float2 original, float angle ){
				float sinX = sin ( angle );
				float cosX = cos ( angle );
				float sinY = sin ( angle );
				float2x2 rotationMatrix = float2x2( cosX, -sinX, sinY, cosX);
				return mul(original, rotationMatrix );
			}

			fixed4 frag (v2f i) : SV_Target
			{
				float clouds = .5 + noise452(i, 1/_Params.x, rotate(float2(_Wind,0), _ParamsB.x)*_Params.z)*2;

				for(int s=1;s<_Samples;s++){
					float s01 = s/(float)(_Samples-1);
					float2 direction = rotate(float2(_Wind,0), lerp(_ParamsB.x, _ParamsB.y, s01)  );
					clouds = clouds - ( noise452(i, 1/lerp(_Params.x, _Params.y, s01), direction * (lerp(_Params.z, _Params.w, s01)))) * lerp(.3, 1, s01);
				}

				float4 shaftColor = i.color*i.color;

				return lerp(shaftColor, shaftColor*clouds, _Cloudy) * _TintColor * (exp(_EmissionGain * 5));
			}

			ENDCG
		}
	}
}
}