Shader "MY/Wind" {
	Properties{
		_MainTex("Base (RGB) Gloss (A)", 2D) = "white" {}
		_Wind("Wind params",Vector) = (0,0,1,1)
		_WindUV("Wind UV params",Vector) = (1,1,1,1)
		_WindEdgeFlutter("Wind edge fultter factor", float) = 0.5
		_WindEdgeFlutterFreqScale("Wind edge fultter freq scale",float) = 0.5
	}

		SubShader{
			Tags {"Queue" = "Transparent" "RenderType" = "Transparent" "LightMode" = "ForwardBase"}
			Blend SrcAlpha OneMinusSrcAlpha
			Cull Off ZWrite Off


			CGINCLUDE
			#include "UnityCG.cginc"
			#include "TerrainEngine.cginc"
			sampler2D _MainTex;
			float4 _MainTex_ST;
			samplerCUBE _ReflTex;

			#ifndef LIGHTMAP_OFF
			// half4 unity_LightmapST;
			// sampler2D unity_Lightmap;
			#endif

			half _WindEdgeFlutter;
			half _WindEdgeFlutterFreqScale;
			half4 _WindUV;

			struct v2f {
				half4 pos : SV_POSITION;
				half2 uv : TEXCOORD0;
				#ifndef LIGHTMAP_OFF
				half2 lmap : TEXCOORD1;
				#endif
				fixed3 spec : TEXCOORD2;
			};

		inline half4 AnimateVertex2(half4 pos, half3 normal, half4 animParams,half4 wind,half2 time)
		{
			// animParams stored in color
			// animParams.x = branch phase
			// animParams.y = edge flutter factor
			// animParams.z = primary factor
			// animParams.w = secondary factor

			half fDetailAmp = 0.1f;
			half fBranchAmp = 0.3f;

			// Phases (object, vertex, branch)
			half fObjPhase = dot(unity_ObjectToWorld[3].xyz, 1);
			half fBranchPhase = fObjPhase + animParams.x;

			half fVtxPhase = dot(pos.xyz, animParams.y + fBranchPhase);

			// x is used for edges; y is used for branches
			half2 vWavesIn = time + half2(fVtxPhase, fBranchPhase);

			// 1.975, 0.793, 0.375, 0.193 are good frequencies
			half4 vWaves = (frac(vWavesIn.xxyy * half4(1.975, 0.793, 0.375, 0.193)) * 2.0 - 1.0);

			vWaves = SmoothTriangleWave(vWaves);
			half2 vWavesSum = vWaves.xz + vWaves.yw;

			// Edge (xz) and branch bending (y)
			half3 bend = animParams.y * fDetailAmp * normal.xyz;
			bend.y = animParams.w * fBranchAmp;
			pos.xyz += ((vWavesSum.xyx * bend) + (wind.xyz * vWavesSum.y * animParams.w)) * wind.w;

			// Primary bending
			// Displace position
			pos.xyz += animParams.z * wind.xyz;

			return pos;
		}



			v2f vert(appdata_full v)
			{
				v2f o;

				half4 wind;

				half bendingFact = min(0,(-v.texcoord.x + _WindUV.x)) * (1 + (_WindUV.y - v.texcoord.y) *_WindUV.z * _SinTime.y);// v.color.a;

				wind.xyz = mul((half3x3)unity_WorldToObject,_Wind.xyz);
				wind.w = _Wind.w  * bendingFact;

				half4 windParams = half4(0,_WindEdgeFlutter,bendingFact.xx);
				half windTime = _Time.y * half2(_WindEdgeFlutterFreqScale,1);
				half4 mdlPos = AnimateVertex2(v.vertex,v.normal,windParams,wind,windTime);

				o.pos = UnityObjectToClipPos(mdlPos);
				o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);

				o.spec = v.color;

				#ifndef LIGHTMAP_OFF
				o.lmap = v.texcoord1.xy * unity_LightmapST.xy + unity_LightmapST.zw;
				#endif

				return o;
			}
			ENDCG


			Pass {
				CGPROGRAM
				#pragma debug
				#pragma vertex vert
				#pragma fragment frag
				#pragma fragmentoption ARB_precision_hint_fastest		
				fixed4 frag(v2f i) : COLOR
				{
					fixed4 tex = tex2D(_MainTex, i.uv);

					fixed4 c;
					c.rgb = tex.rgb;
					c.a = tex.a;

					#ifndef LIGHTMAP_OFF
					fixed3 lm = DecodeLightmap(UNITY_SAMPLE_TEX2D(unity_Lightmap, i.lmap));
					c.rgb *= lm;
					#endif

					return c;
				}
				ENDCG
			}
		}
}