/*
	Author: Alberto Mellado Cruz
	Date: 09/11/2017

	Comments: 
	This is just a test that would depend on the 3D Model used.
	Vertex animations would allow the use of GPU Instancing, 
	enabling the use of a dense amount of animated fish.
  	The code may not be optimized but it was just a test
*/

Shader "Custom/FishAnimation" {
	Properties{
		_MainTex("Albedo (RGB)", 2D) = "white" {}
		_SpeedX("SpeedX", Range(0, 10)) = 1
		_FrequencyX("FrequencyX", Range(0, 10)) = 1
		_AmplitudeX("AmplitudeX", Range(0, 0.2)) = 1
		_SpeedY("SpeedY", Range(0, 10)) = 1
		_FrequencyY("FrequencyY", Range(0, 10)) = 1
		_AmplitudeY("AmplitudeY", Range(0, 0.2)) = 1
		_SpeedZ("SpeedZ", Range(0, 10)) = 1
		_FrequencyZ("FrequencyZ", Range(0, 10)) = 1
		_AmplitudeZ("AmplitudeZ", Range(0,  2)) = 1
		_HeadLimit("HeadLimit", Range(-2,  2)) = 0.05
	}
		SubShader{
		Tags{ "RenderType" = "Opaque"
			"RenderPipeline" = "UniversalPipeline"
		}
		Cull off

		Pass{

		CGPROGRAM
	#pragma vertex vert
	#pragma fragment frag
	#include "UnityCG.cginc"

	sampler2D _MainTex;
	float4 _MainTex_ST;

	struct v2f {
		float4 pos : SV_POSITION;
		float2 uv : TEXCOORD0;
	};
	
	// X AXIS

	float _SpeedX;
	float _FrequencyX;
	float _AmplitudeX;
	
	// Y AXIS

	float _SpeedY;
	float _FrequencyY;
	float _AmplitudeY;

	// Z AXIS
	
	float _SpeedZ;
	float _FrequencyZ;
	float _AmplitudeZ;

	// Head Limit (Head wont shake so much)
	
	float _HeadLimit;

	v2f vert(appdata_base v)
	{
		v2f o;

		//Z AXIS

		v.vertex.z += sin((v.vertex.z + _Time.y * _SpeedX) * _FrequencyX)* _AmplitudeX;		

		//Y AXIS

		v.vertex.y += sin((v.vertex.z + _Time.y * _SpeedY) * _FrequencyY)* _AmplitudeY;

		//X AXIS

		if (v.vertex.z > _HeadLimit)
		{
			v.vertex.x += sin((0.05 + _Time.y * _SpeedZ) * _FrequencyZ)* _AmplitudeZ * _HeadLimit;
		}
		else
		{
			v.vertex.x += sin((v.vertex.z + _Time.y * _SpeedZ) * _FrequencyZ)* _AmplitudeZ * v.vertex.z;
		}


		o.pos = UnityObjectToClipPos(v.vertex);
		o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
		return o;
		
	}

	fixed4 frag(v2f i) : SV_Target
	{
		return tex2D(_MainTex, i.uv);
	}

		ENDCG

	}
	}
		FallBack "Diffuse"
}