《Unity Shader 入门精要》从Bulit-in 到URP （HLSL）Chapter14.1-卡通风格的衬着

lingli125 发表于 2024-7-15 18:17

前言：

已经进入“高级篇”啦，但愿大师多多撑持，多多存眷，这将对我发生非常愉悦的正反馈~

“《Unity Shader 入门精要》从Bulit-in 到URP”是一个辅佐Unity Shader学习者以冯乐乐女神《Unity Shader 入门精要》为基础学习用HLSL语言编写URP着色器的案例教学系列。

作者自学能力有限，抛砖引玉，如有建议和问题请各位大佬和同仁交流斧正。
Bulit-in版：

// Upgrade NOTE: replaced '_Object2World' with 'unity_ObjectToWorld'
// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader ”Unity Shaders Book/Chapter 14/Toon Shading” {
Properties {
_Color (”Color Tint”, Color) = (1, 1, 1, 1)
_MainTex (”Main Tex”, 2D) = ”white” {}
_Ramp (”Ramp Texture”, 2D) = ”white” {}
_Outline (”Outline”, Range(0, 1)) = 0.1
_OutlineColor (”Outline Color”, Color) = (0, 0, 0, 1)
_Specular (”Specular”, Color) = (1, 1, 1, 1)
_SpecularScale (”Specular Scale”, Range(0, 0.1)) = 0.01
}
SubShader {
Tags { ”RenderType”=”Opaque” ”Queue”=”Geometry”}

Pass {
NAME ”OUTLINE”

Cull Front

CGPROGRAM

#pragma vertex vert
#pragma fragment frag

#include ”UnityCG.cginc”

float _Outline;
fixed4 _OutlineColor;

struct a2v {
float4 vertex : POSITION;
float3 normal : NORMAL;
};

struct v2f {
   float4 pos : SV_POSITION;
};

v2f vert (a2v v) {
v2f o;

float4 pos = mul(UNITY_MATRIX_MV, v.vertex);
float3 normal = mul((float3x3)UNITY_MATRIX_IT_MV, v.normal);
normal.z = -0.5;
pos = pos + float4(normalize(normal), 0) * _Outline;
o.pos = mul(UNITY_MATRIX_P, pos);

return o;
}

float4 frag(v2f i) : SV_Target {
return float4(_OutlineColor.rgb, 1);
}

ENDCG
}

Pass {
Tags { ”LightMode”=”ForwardBase” }

Cull Back

CGPROGRAM

#pragma vertex vert
#pragma fragment frag

#pragma multi_compile_fwdbase

#include ”UnityCG.cginc”
#include ”Lighting.cginc”
#include ”AutoLight.cginc”
#include ”UnityShaderVariables.cginc”

fixed4 _Color;
sampler2D _MainTex;
float4 _MainTex_ST;
sampler2D _Ramp;
fixed4 _Specular;
fixed _SpecularScale;

struct a2v {
float4 vertex : POSITION;
float3 normal : NORMAL;
float4 texcoord : TEXCOORD0;
float4 tangent : TANGENT;
};

struct v2f {
float4 pos : POSITION;
float2 uv : TEXCOORD0;
float3 worldNormal : TEXCOORD1;
float3 worldPos : TEXCOORD2;
SHADOW_COORDS(3)
};

v2f vert (a2v v) {
v2f o;

o.pos = UnityObjectToClipPos( v.vertex);
o.uv = TRANSFORM_TEX (v.texcoord, _MainTex);
o.worldNormal= UnityObjectToWorldNormal(v.normal);
o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;

TRANSFER_SHADOW(o);

return o;
}

float4 frag(v2f i) : SV_Target {
fixed3 worldNormal = normalize(i.worldNormal);
fixed3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));
fixed3 worldViewDir = normalize(UnityWorldSpaceViewDir(i.worldPos));
fixed3 worldHalfDir = normalize(worldLightDir + worldViewDir);

fixed4 c = tex2D (_MainTex, i.uv);
fixed3 albedo = c.rgb * _Color.rgb;

fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;

UNITY_LIGHT_ATTENUATION(atten, i, i.worldPos);

fixed diff =dot(worldNormal, worldLightDir);
diff = (diff * 0.5 + 0.5) * atten;

fixed3 diffuse = _LightColor0.rgb * albedo * tex2D(_Ramp, float2(diff, diff)).rgb;

fixed spec = dot(worldNormal, worldHalfDir);
fixed w = fwidth(spec) * 2.0;
fixed3 specular = _Specular.rgb * lerp(0, 1, smoothstep(-w, w, spec + _SpecularScale - 1)) * step(0.0001, _SpecularScale);

return fixed4(ambient + diffuse + specular, 1.0);
}

ENDCG
}
}
FallBack ”Diffuse”
}

URP版：

Unity项目源码：
Shader ”Unlit/Chapter14-ToonShading”
{
Properties {
_Color (”Color Tint”, Color) = (1, 1, 1, 1)
_MainTex (”Main Tex”, 2D) = ”white” {}
_Ramp (”Ramp Texture”, 2D) = ”white” {}
_Outline (”Outline”, Range(0, 1)) = 0.1
_OutlineColor (”Outline Color”, Color) = (0, 0, 0, 1)
_Specular (”Specular”, Color) = (1, 1, 1, 1)
_SpecularScale (”Specular Scale”, Range(0, 0.1)) = 0.01
}
SubShader
{
   Tags {”RenderPipeline” = ”UniversalPipeline” ”RenderType”=”Opaque” ”Queue”=”Geometry”}

   HLSLINCLUDE
   #include ”Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl”
#include ”Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”

   CBUFFER_START(UnityPerMaterial)
         float _Outline;
half4 _OutlineColor;
         half4 _Color;
float4 _MainTex_ST;
half4 _Specular;
half _SpecularScale;
   CBUFFER_END

   ENDHLSL

   UsePass ”Universal Render Pipeline/Lit/ShadowCaster”

Pass {
NAME ”OUTLINE”

Cull Front

HLSLPROGRAM

#pragma vertex vert
#pragma fragment frag

struct a2v {
float4 vertex : POSITION;
float3 normal : NORMAL;
};

struct v2f {
   float4 pos : SV_POSITION;
};

v2f vert (a2v v) {
v2f o;

float4 pos = mul(UNITY_MATRIX_MV, v.vertex);
float3 normal = mul((float3x3)UNITY_MATRIX_IT_MV, v.normal);
            //把顶点法线转换到view空间
normal.z = -0.5;
pos = pos + float4(normalize(normal), 0) * _Outline;
            //在view空间完成顶点扩张
o.pos = mul(UNITY_MATRIX_P, pos);

return o;
}

float4 frag(v2f i) : SV_Target {
return float4(_OutlineColor.rgb, 1);
}

ENDHLSL
}

Pass {
Tags { ”LightMode”=”UniversalForward” }

Cull Back

HLSLPROGRAM

#pragma vertex vert
#pragma fragment frag

         TEXTURE2D(_MainTex);    SAMPLER(sampler_MainTex);
         TEXTURE2D(_Ramp);    SAMPLER(sampler_Ramp);

struct a2v {
float4 vertex : POSITION;
float3 normal : NORMAL;
float4 texcoord : TEXCOORD0;
//float4 tangent : TANGENT;
};

struct v2f {
float4 pos : POSITION;
float2 uv : TEXCOORD0;
float3 worldNormal : TEXCOORD1;
float3 worldPos : TEXCOORD2;
};

v2f vert (a2v v) {
v2f o;

            VertexPositionInputs positionInputs = GetVertexPositionInputs(v.vertex.xyz);
//o.pos = TransformObjectToHClip( v.vertex);
            o.pos = positionInputs.positionCS;
o.uv = TRANSFORM_TEX (v.texcoord, _MainTex);
o.worldNormal= TransformObjectToWorldNormal(v.normal);
//o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
o.worldPos = positionInputs.positionWS;

return o;
}

float4 frag(v2f i) : SV_Target {
Light mainLight = GetMainLight();
//获取光源信息的函数
            half3 worldLightDir = normalize(TransformObjectToWorldDir(mainLight.direction));
            //half3 worldNormal = normalize(i.worldNormal);
//half3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));
half3 worldViewDir = normalize(_WorldSpaceCameraPos.xyz - i.worldPos);
half3 worldHalfDir = normalize(worldLightDir + worldViewDir);

half4 c = SAMPLE_TEXTURE2D (_MainTex, sampler_MainTex, i.uv);
half3 albedo = c.rgb * _Color.rgb;

half3 ambient = half3(unity_SHAr.w, unity_SHAg.w, unity_SHAb.w) * albedo;
            half atten = mainLight.distanceAttenuation;

//UNITY_LIGHT_ATTENUATION(atten, i, i.worldPos);

half diff =dot(i.worldNormal, worldLightDir);
diff = (diff * 0.5 + 0.5) * atten;

half3 diffuse = mainLight.color * albedo * SAMPLE_TEXTURE2D(_Ramp, sampler_Ramp, float2(diff, diff)).rgb;

half spec = dot(i.worldNormal, worldHalfDir);
half w = fwidth(spec) * 2.0;
            //此函数计算以下内容： abs (ddx (x) ) + abs (ddy (x) ),即相邻像素点该数值的变化度。
half3 specular = mainLight.color * _Specular.rgb * lerp(0, 1, smoothstep(-w, w, spec + _SpecularScale - 1)) * step(0.0001, _SpecularScale);

return half4(ambient + diffuse + specular, 1.0);
}

ENDHLSL
}
}
FallBack ”Packages/com.unity.render-pipelines.universal/FallbackError”
}

效果图：

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《Unity Shader 入门精要》从Bulit-in 到URP （HLSL）Chapter14.1-卡通风格的衬着