Shader "MoreMountains/MMSkybox"
{
	Properties
	{
		_TopColor("Top Color", Color) = (1,1,1,0)
		_BottomColor("Bottom Color", Color) = (1,0.6,0,0)
		_Saturation("Saturation", Float) = 1
		_Intensity("Intensity", Float) = 1
		[Toggle(_SCREENSPACE)] _ScreenSpace("Screen Space", Float) = 0
	}
	
	SubShader
	{	
		Tags { "RenderType"="Opaque" }
		LOD 100

		CGINCLUDE
		#pragma target 3.0
		ENDCG
		Blend Off
		Cull Back
		ColorMask RGBA
		ZWrite On
		ZTest LEqual
		Offset 0 , 0
		
		
		
		Pass
		{
			Name "Unlit"
			Tags { "LightMode"="ForwardBase" }
			CGPROGRAM

			#ifndef UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX
			#define UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input)
			#endif
			#pragma vertex vert
			#pragma fragment frag
			#pragma multi_compile_instancing
			#include "UnityCG.cginc"
			#pragma shader_feature_local _SCREENSPACE

			struct appdata
			{
				float4 vertex : POSITION;
				float4 color : COLOR;
				UNITY_VERTEX_INPUT_INSTANCE_ID
				
			};
			
			struct v2f
			{
				float4 vertex : SV_POSITION;
				#ifdef ASE_NEEDS_FRAG_WORLD_POSITION
					float3 worldPos : TEXCOORD0;
				#endif
				UNITY_VERTEX_INPUT_INSTANCE_ID
				UNITY_VERTEX_OUTPUT_STEREO
				float4 ase_texcoord1 : TEXCOORD1;
				float4 ase_texcoord2 : TEXCOORD2;
			};

			uniform float4 _TopColor;
			uniform float4 _BottomColor;
			uniform float _Saturation;
			uniform float _Intensity;

			
			v2f vert ( appdata v )
			{
				v2f o;
				UNITY_SETUP_INSTANCE_ID(v);
				UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
				UNITY_TRANSFER_INSTANCE_ID(v, o);

				float4 ase_clipPos = UnityObjectToClipPos(v.vertex);
				float4 screenPos = ComputeScreenPos(ase_clipPos);
				o.ase_texcoord2 = screenPos;				
				o.ase_texcoord1 = v.vertex;
				float3 vertexValue = float3(0, 0, 0);
				#if ASE_ABSOLUTE_VERTEX_POS
					vertexValue = v.vertex.xyz;
				#endif
				vertexValue = vertexValue;
				#if ASE_ABSOLUTE_VERTEX_POS
					v.vertex.xyz = vertexValue;
				#else
					v.vertex.xyz += vertexValue;
				#endif
				o.vertex = UnityObjectToClipPos(v.vertex);

				#ifdef ASE_NEEDS_FRAG_WORLD_POSITION
					o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
				#endif
				return o;
			}
			
			fixed4 frag (v2f i ) : SV_Target
			{
				UNITY_SETUP_INSTANCE_ID(i);
				UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(i);
				fixed4 finalColor;
				#ifdef ASE_NEEDS_FRAG_WORLD_POSITION
					float3 WorldPosition = i.worldPos;
				#endif
				float4 screenPos = i.ase_texcoord2;
				float4 ase_screenPosNorm = screenPos / screenPos.w;
				ase_screenPosNorm.z = ( UNITY_NEAR_CLIP_VALUE >= 0 ) ? ase_screenPosNorm.z : ase_screenPosNorm.z * 0.5 + 0.5;
				#ifdef _SCREENSPACE
					float staticSwitch13 = ase_screenPosNorm.y;
				#else
					float staticSwitch13 = i.ase_texcoord1.xyz.y;
				#endif
				float4 lerpResult3 = lerp( _BottomColor , _TopColor , pow( saturate( ( staticSwitch13 * _Saturation) ) , _Intensity ));
				finalColor = lerpResult3;
				return finalColor;
			}
			ENDCG
		}
	}	
}