ToonSnowBuildup.shader

Shader "Toon/Lit Snow Buildup" {
	Properties{
		_Color("Main Color", Color) = (0.5,0.5,0.5,1)
		_MainTex("Base (RGB)", 2D) = "white" {}
	_Ramp("Toon Ramp (RGB)", 2D) = "gray" {}
	_SnowRamp("Snow Toon Ramp (RGB)", 2D) = "gray" {}
	_SnowAngle("Angle of snow buildup", Vector) = (0,1,0)
		_SnowColor("Snow Base Color", Color) = (0.5,0.5,0.5,1)
		_TColor("Snow Top Color", Color) = (0.5,0.5,0.5,1)
		_RimColor("Snow Rim Color", Color) = (0.5,0.5,0.5,1)
		_RimPower("Snow Rim Power", Range(0,4)) = 3
		_SnowSize("Snow Amount", Range(-2,2)) = 1
		_Height("Snow Height", Range(0,0.2)) = 0.1



	}

		SubShader{
		Tags{ "RenderType" = "Opaque" }
		LOD 200
		Cull Off
		CGPROGRAM

#pragma surface surf ToonRamp vertex:disp addshadow
		sampler2D _Ramp;

	// custom lighting function that uses a texture ramp based
	// on angle between light direction and normal
#pragma lighting ToonRamp exclude_path:prepass
	inline half4 LightingToonRamp(SurfaceOutput s, half3 lightDir, half atten)
	{
#ifndef USING_DIRECTIONAL_LIGHT
		lightDir = normalize(lightDir);
#endif

		half d = dot(s.Normal, lightDir)*0.5 + 0.5;
		half3 ramp = tex2D(_Ramp, float2(d,d)).rgb;

		half4 c;
		c.rgb = s.Albedo * _LightColor0.rgb * ramp * (atten * 2);
		c.a = 0;
		return c;
	}


	sampler2D _MainTex;
	sampler2D _SnowRamp;

	float4 _Color;
	float4 _SnowColor;
	float4 _TColor;
	float4 _SnowAngle;
	float4 _RimColor;

	float _SnowSize;
	float _Height;
	float _RimPower;

	struct Input {
		float2 uv_MainTex : TEXCOORD0;
		float3 worldPos;
		float3 viewDir;
		float3 lightDir;

	};

	struct appdata {
		float4 vertex : POSITION;
		float3 normal : NORMAL;
	};

	void disp(inout appdata_full v, out Input o)
	{
		UNITY_INITIALIZE_OUTPUT(Input, o);
		o.lightDir = WorldSpaceLightDir(v.vertex); // light direction for snow ramp
		float4 snowC = mul(_SnowAngle , unity_ObjectToWorld); // snow direction convertion to worldspace
		if (dot(v.normal, snowC.xyz) >= _SnowSize ) {
			v.vertex.xyz += v.normal * _Height;// scale vertices along normal
		}

	}

	void surf(Input IN, inout SurfaceOutput o) {

		float3 localPos = (IN.worldPos - mul(unity_ObjectToWorld, float4(0, 0, 0, 1)).xyz); // local position for snow color blend
		half d = dot(o.Normal, IN.lightDir)*0.5 + 0.5; // light value for snow toon ramp
		half4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color; // main texture
		half3 rampS = tex2D(_SnowRamp, float2(d, d)).rgb; // snow toon ramp
		o.Albedo = c.rgb * _Color;// base color
		half rim = 1.0 - saturate(dot(normalize(IN.viewDir), o.Normal)); // rimlight
		if (dot( o.Normal, _SnowAngle.xyz) >= _SnowSize -0.4) { // if dot product result is higher than snow amount, we turn it into snow
			o.Albedo = (lerp(_SnowColor * rampS, _TColor * rampS, saturate(localPos.y))); // blend base snow with top snow based on position
			o.Emission = _RimColor.rgb *pow(rim, _RimPower);// add glow rimlight to snow
		}
		o.Alpha = c.a;
	}
	ENDCG

	}

		Fallback "Diffuse"
}