Unity 5.6 Deferred Cel Shading Modification

ToonDeferredShading2017.shader

// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)
// Modifications by David Leon. Copyright (c) 2017 Lince Works SL. MIT license (see license.txt)

Shader "ToonDeferredShading2017" {
Properties {
	_LightTexture0 ("", any) = "" {}
	_LightTextureB0 ("", 2D) = "" {}
	_ShadowMapTexture ("", any) = "" {}
	_SrcBlend ("", Float) = 1
	_DstBlend ("", Float) = 1
}
SubShader {

// Pass 1: Lighting pass
//  LDR case - Lighting encoded into a subtractive ARGB8 buffer
//  HDR case - Lighting additively blended into floating point buffer
Pass {
	ZWrite Off
	Blend [_SrcBlend] [_DstBlend]

CGPROGRAM
#define UNITY_BRDF_PBS BRDF_Unity_Toon
#pragma target 3.0
#pragma vertex vert_deferred
#pragma fragment frag
#pragma multi_compile_lightpass
#pragma multi_compile ___ UNITY_HDR_ON

#pragma exclude_renderers nomrt

#include "UnityCG.cginc"
#include "UnityDeferredLibrary.cginc"
//#include "UnityPBSLighting.cginc"
#include "UnityStandardUtils.cginc"
#include "UnityGBuffer.cginc"
#include "UnityStandardBRDF.cginc"
#include "UnityStandardBRDFCustom.cginc"

sampler2D _CameraGBufferTexture0;
sampler2D _CameraGBufferTexture1;
sampler2D _CameraGBufferTexture2;
		
half4 CalculateLight (unity_v2f_deferred i)
{
	float3 wpos;
	float2 uv;
	float atten, fadeDist;
	UnityLight light;
	UNITY_INITIALIZE_OUTPUT(UnityLight, light);
	UnityDeferredCalculateLightParams(i, wpos, uv, light.dir, atten, fadeDist);

	light.color = _LightColor.rgb * atten;

	// unpack Gbuffer
	half4 gbuffer0 = tex2D (_CameraGBufferTexture0, uv);
	half4 gbuffer1 = tex2D (_CameraGBufferTexture1, uv);
	half4 gbuffer2 = tex2D (_CameraGBufferTexture2, uv);
	UnityStandardData data = UnityStandardDataFromGbuffer(gbuffer0, gbuffer1, gbuffer2);

	float3 eyeVec = normalize(wpos-_WorldSpaceCameraPos);
	half oneMinusReflectivity = 1 - SpecularStrength(data.specularColor.rgb);

	UnityIndirect ind;
	UNITY_INITIALIZE_OUTPUT(UnityIndirect, ind);
	ind.diffuse = 0;
	ind.specular = 0;

  half4 res = UNITY_BRDF_PBS (data.diffuseColor, data.specularColor, oneMinusReflectivity, data.smoothness, data.normalWorld, -eyeVec, light, ind);
	return res;
}

#ifdef UNITY_HDR_ON
half4
#else
fixed4
#endif
frag (unity_v2f_deferred i) : SV_Target
{
	half4 c = CalculateLight(i);
	#ifdef UNITY_HDR_ON
	return c;
	#else
	return exp2(-c);
	#endif
}

ENDCG
}


// Pass 2: Final decode pass.
// Used only with HDR off, to decode the logarithmic buffer into the main RT
Pass {
	ZTest Always Cull Off ZWrite Off
	Stencil {
		ref [_StencilNonBackground]
		readmask [_StencilNonBackground]
		// Normally just comp would be sufficient, but there's a bug and only front face stencil state is set (case 583207)
		compback equal
		compfront equal
	}

CGPROGRAM
#pragma target 3.0
#pragma vertex vert
#pragma fragment frag
#pragma exclude_renderers nomrt

#include "UnityCG.cginc"

sampler2D _LightBuffer;
struct v2f {
	float4 vertex : SV_POSITION;
	float2 texcoord : TEXCOORD0;
};

v2f vert (float4 vertex : POSITION, float2 texcoord : TEXCOORD0)
{
	v2f o;
	o.vertex = UnityObjectToClipPos(vertex);
	o.texcoord = texcoord.xy;
#ifdef UNITY_SINGLE_PASS_STEREO
	o.texcoord = TransformStereoScreenSpaceTex(o.texcoord, 1.0f);
#endif
	return o;
}

fixed4 frag (v2f i) : SV_Target
{
	return -log2(tex2D(_LightBuffer, i.texcoord));
}
ENDCG 
}

}
Fallback Off
}

UnityStandardBRDFCustom.cginc

#include "UnityCG.cginc"
#include "UnityStandardConfig.cginc"
#include "UnityLightingCommon.cginc"

half4 BRDF_Unity_Toon(half3 diffColor, half3 specColor, half oneMinusReflectivity, half smoothness,
	half3 normal, half3 viewDir,
	UnityLight light, UnityIndirect gi)
{
	half3 halfDir = Unity_SafeNormalize(light.dir + viewDir);

	half nl = smoothstep(0.0, 0.05, saturate(dot(normal, light.dir)));
	half nh = saturate(dot(normal, halfDir));
	half nv = saturate(dot(normal, viewDir));
	half lh = saturate(dot(light.dir, halfDir));

	// Specular term
	half perceptualRoughness = SmoothnessToPerceptualRoughness(smoothness);
	half roughness = PerceptualRoughnessToRoughness(perceptualRoughness);

#if UNITY_BRDF_GGX

	// GGX Distribution multiplied by combined approximation of Visibility and Fresnel
	// See "Optimizing PBR for Mobile" from Siggraph 2015 moving mobile graphics course
	// https://community.arm.com/events/1155
	half a = roughness;
	half a2 = a*a;

	half d = nh * nh * (a2 - 1.h) + 1.00001h;
#ifdef UNITY_COLORSPACE_GAMMA
	// Tighter approximation for Gamma only rendering mode!
	// DVF = sqrt(DVF);
	// DVF = (a * sqrt(.25)) / (max(sqrt(0.1), lh)*sqrt(roughness + .5) * d);
	half specularTerm = a / (max(0.32h, lh) * (1.5h + roughness) * d);
#else
	half specularTerm = a2 / (max(0.1h, lh*lh) * (roughness + 0.5h) * (d * d) * 4);
#endif

	// on mobiles (where half actually means something) denominator have risk of overflow
	// clamp below was added specifically to "fix" that, but dx compiler (we convert bytecode to metal/gles)
	// sees that specularTerm have only non-negative terms, so it skips max(0,..) in clamp (leaving only min(100,...))
#if defined (SHADER_API_MOBILE)
	specularTerm = specularTerm - 1e-4h;
#endif

#else

	// Legacy
	half specularPower = PerceptualRoughnessToSpecPower(perceptualRoughness);
	// Modified with approximate Visibility function that takes roughness into account
	// Original ((n+1)*N.H^n) / (8*Pi * L.H^3) didn't take into account roughness
	// and produced extremely bright specular at grazing angles

	half invV = lh * lh * smoothness + perceptualRoughness * perceptualRoughness; // approx ModifiedKelemenVisibilityTerm(lh, perceptualRoughness);
	half invF = lh;

	half specularTerm = ((specularPower + 1) * pow(nh, specularPower)) / (8 * invV * invF + 1e-4h);

#ifdef UNITY_COLORSPACE_GAMMA
	specularTerm = sqrt(max(1e-4h, specularTerm));
#endif

#endif

#if defined (SHADER_API_MOBILE)
	specularTerm = clamp(specularTerm, 0.0, 100.0); // Prevent FP16 overflow on mobiles
#endif
#if defined(_SPECULARHIGHLIGHTS_OFF)
	specularTerm = 0.0;
#endif

	// surfaceReduction = Int D(NdotH) * NdotH * Id(NdotL>0) dH = 1/(realRoughness^2+1)

	// 1-0.28*x^3 as approximation for (1/(x^4+1))^(1/2.2) on the domain [0;1]
	// 1-x^3*(0.6-0.08*x)   approximation for 1/(x^4+1)
#ifdef UNITY_COLORSPACE_GAMMA
	half surfaceReduction = 0.28;
#else
	half surfaceReduction = (0.6 - 0.08*perceptualRoughness);
#endif

	surfaceReduction = 1.0 - roughness*perceptualRoughness*surfaceReduction;

	half grazingTerm = saturate(smoothness + (1 - oneMinusReflectivity));
	half3 color = (diffColor + specularTerm * specColor) * light.color * nl
		+ gi.diffuse * diffColor
		+ surfaceReduction * gi.specular * FresnelLerpFast(specColor, grazingTerm, nv);

	return half4(color, 1);
}

Thanks for the code and article at http://www.gamasutra.com/blogs/DavidLeon/20170519/298374/NextGen_Cel_Shading_in_Unity_56.php

https://www.gamedeveloper.com/programming/next-gen-cel-shading-in-unity-5-6