SpritesDiffuseWave

// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)
// from 2017.1.1 built-in Sprites-Diffuse Shader
// and https://forum.unity.com/threads/shader-moving-trees-grass-in-wind-outside-of-terrain.230911/
Shader "Northway/SpritesDiffuseWave" {
    Properties {
        [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
        _Color ("Tint", Color) = (1,1,1,1)
        [MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
        [HideInInspector] _RendererColor ("RendererColor", Color) = (1,1,1,1)
        [HideInInspector] _Flip ("Flip", Vector) = (1,1,1,1)
        [PerRendererData] _AlphaTex ("External Alpha", 2D) = "white" {}
        [PerRendererData] _EnableExternalAlpha ("Enable External Alpha", Float) = 0
		_ShakeDisplacement ("Displacement", Range (0, 1.0)) = 1.0
		_ShakeTime ("Shake Time", Range (0, 1.0)) = 1.0
		_ShakeWindspeed ("Shake Windspeed", Range (0, 1.0)) = 1.0
		_ShakeBending ("Shake Bending", Range (0, 1.0)) = 1.0
    }

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

        Cull Off
        Lighting Off
        ZWrite Off
        Blend One OneMinusSrcAlpha

        CGPROGRAM
        #pragma surface surf Lambert vertex:vert nofog nolightmap nodynlightmap keepalpha noinstancing
        #pragma multi_compile _ PIXELSNAP_ON
        #pragma multi_compile _ ETC1_EXTERNAL_ALPHA
        #include "UnitySprites.cginc"

		float _ShakeDisplacement;
		float _ShakeTime;
		float _ShakeWindspeed;
		float _ShakeBending;

        struct Input {
            float2 uv_MainTex;
            fixed4 color;
        };

		void FastSinCos (float4 val, out float4 s, out float4 c) {
			val = val * 6.408849 - 3.1415927;
			float4 r5 = val * val;
			float4 r6 = r5 * r5;
			float4 r7 = r6 * r5;
			float4 r8 = r6 * r5;
			float4 r1 = r5 * val;
			float4 r2 = r1 * r5;
			float4 r3 = r2 * r5;
			float4 sin7 = {1, -0.16161616, 0.0083333, -0.00019841} ;
			float4 cos8  = {-0.5, 0.041666666, -0.0013888889, 0.000024801587} ;
			s =  val + r1 * sin7.y + r2 * sin7.z + r3 * sin7.w;
			c = 1 + r5 * cos8.x + r6 * cos8.y + r7 * cos8.z + r8 * cos8.w;
		}

        void vert (inout appdata_full v, out Input o) {
            //v.vertex.xy *= _Flip.xy;

            //#if defined(PIXELSNAP_ON)
            //v.vertex = UnityPixelSnap (v.vertex);
            //#endif

			// waving
			float factor = (1 - _ShakeDisplacement -  v.color.r) * 0.5;
			const float _WindSpeed  = (_ShakeWindspeed  +  v.color.g );
			const float _WaveScale = _ShakeDisplacement;
			const float4 _waveXSize = float4(0.048, 0.06, 0.24, 0.096);
			const float4 _waveZSize = float4 (0.024, .08, 0.08, 0.2);
			const float4 waveSpeed = float4 (1.2, 2, 1.6, 4.8);
			float4 _waveXmove = float4(0.024, 0.04, -0.12, 0.096);
			float4 _waveZmove = float4 (0.006, .02, -0.02, 0.1);
			float4 waves;
			waves = v.vertex.x * _waveXSize;
			waves += v.vertex.z * _waveZSize;
			//waves += _Time.x * (1 - _ShakeTime * 2 - v.color.b ) * waveSpeed *_WindSpeed;
			waves += 0.5 * (1 - _ShakeTime * 2 - v.color.b ) * waveSpeed *_WindSpeed;
			float4 s, c;
			waves = frac (waves);
			FastSinCos (waves, s,c);
			float waveAmount = v.texcoord.y * (v.color.a + _ShakeBending);
			s *= waveAmount;
			s *= normalize (waveSpeed);
			s = s * s;
			float fade = dot (s, 1.3);
			s = s * s;
			float3 waveMove = float3 (0,0,0);
			waveMove.x = dot (s, _waveXmove);
			waveMove.z = dot (s, _waveZmove);
			//v.vertex.xz -= mul ((float3x3)unity_WorldToObject, waveMove).xz;
			v.vertex.xz -= waveMove.xz;

            //UNITY_INITIALIZE_OUTPUT(Input, o);
			o = (Input)0;
            o.color = v.color * _Color * _RendererColor;
        }

        void surf (Input IN, inout SurfaceOutput o) {
            fixed4 c = SampleSpriteTexture (IN.uv_MainTex) * IN.color;
            o.Albedo = c.rgb * c.a;
            o.Alpha = c.a;
        }
        ENDCG
    }

	Fallback "Transparent/VertexLit"
}