US3S2L10——渐变纹理综合实现
渐变纹理综合实现
接下来将渐变纹理的映射实现融合到之前实现的法线纹理 Shader 内,
这里复用之前实现的 切线空间下的法线纹理 Shader
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| Shader "TeachShader/Lesson51" { Properties { _MainColor("MainColor", Color) = (1, 1, 1, 1) _MainTex("MainTex", 2D) = ""{} _BumpMap("BumpMap", 2D) = ""{} _BumpScale("BumpScale", Range(0, 1)) = 1 _SpecularColor("SpecularColor", Color) = (1, 1, 1, 1) _SpecularNum("SpecularNum", Range(0, 20)) = 18 } SubShader { Pass { Tags { "LightMode" = "ForwardBase" }
CGPROGRAM #pragma vertex vert #pragma fragment frag
#include "UnityCG.cginc" #include "Lighting.cginc"
struct v2f { float4 pos: SV_POSITION; float4 uv: TEXCOORD0; float3 lightDir: TEXCOORD1; float3 viewDir: TEXCOORD2; };
float4 _MainColor; sampler2D _MainTex; float4 _MainTex_ST; sampler2D _BumpMap; float4 _BumpMap_ST; float _BumpScale; float4 _SpecularColor; fixed _SpecularNum;
v2f vert (appdata_full v) { v2f data; data.pos = UnityObjectToClipPos(v.vertex); data.uv.xy = v.texcoord.xy * _MainTex_ST.xy + _MainTex_ST.zw; data.uv.zw = v.texcoord.xy * _BumpMap_ST.xy + _BumpMap_ST.zw;
float3 binormal = cross(normalize(v.tangent), normalize(v.normal)) * v.tangent.w; float3x3 rotation = float3x3( v.tangent.xyz, binormal, v.normal ); data.lightDir = mul(rotation, ObjSpaceLightDir(v.vertex)); data.viewDir = mul(rotation, ObjSpaceViewDir(v.vertex));
return data; }
fixed4 frag (v2f i) : SV_Target { float4 packedNormal = tex2D(_BumpMap, i.uv.zw); float3 tangentNormal = UnpackNormal(packedNormal); tangentNormal.xy *= _BumpScale; tangentNormal.z = sqrt(1.0 - saturate(dot(tangentNormal.xy, tangentNormal.xy)));
fixed3 albedo = tex2D(_MainTex, i.uv.xy).rgb * _MainColor.rgb;
fixed3 lambertColor = _LightColor0.rgb * albedo.rgb * max(0, dot(tangentNormal, normalize(i.lightDir))); float3 halfA = normalize(normalize(i.viewDir) + normalize(i.lightDir)); fixed3 specularColor = _LightColor0.rgb * _SpecularColor.rgb * pow(max(0, dot(tangentNormal, halfA)), _SpecularNum); fixed3 color = UNITY_LIGHTMODEL_AMBIENT.rgb * albedo + lambertColor + specularColor;
return fixed4(color.rgb, 1); } ENDCG } } }
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然后,修改上述代码的实现,将渐变纹理贴图计算融合到其中
关键点:将原本的兰伯特光照模型修改为渐变纹理的计算方式(半兰伯特光照模型映射渐变纹理颜色)
因此,属性需要添加渐变纹理 _RampTex
:
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| Properties { _MainColor("MainColor", Color) = (1, 1, 1, 1) _MainTex("MainTex", 2D) = ""{} _BumpMap("BumpMap", 2D) = ""{} _BumpScale("BumpScale", Range(0, 1)) = 1 _RampTex("_RampTex", 2D) = ""{} _SpecularColor("SpecularColor", Color) = (1, 1, 1, 1) _SpecularNum("SpecularNum", Range(0, 20)) = 18 }
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同时,片元着色器的漫反射计算部分也要修改为:
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| struct v2f { float4 pos: SV_POSITION; float4 uv: TEXCOORD0; float3 lightDir: TEXCOORD1; float3 viewDir: TEXCOORD2; };
float4 _MainColor; sampler2D _MainTex; float4 _MainTex_ST; sampler2D _BumpMap; float4 _BumpMap_ST; sampler2D _RampTex; float4 _RampTex_ST; float _BumpScale; float4 _SpecularColor; fixed _SpecularNum;
fixed4 frag (v2f i) : SV_Target { float4 packedNormal = tex2D(_BumpMap, i.uv.zw); float3 tangentNormal = UnpackNormal(packedNormal); tangentNormal.xy *= _BumpScale; tangentNormal.z = sqrt(1.0 - saturate(dot(tangentNormal.xy, tangentNormal.xy)));
fixed3 albedo = tex2D(_MainTex, i.uv.xy).rgb * _MainColor.rgb;
fixed halfLambertNum = dot(tangentNormal, normalize(i.lightDir)) * 0.5 + 0.5; fixed3 diffuseColor = _LightColor0.rgb * albedo.rgb * tex2D(_RampTex, fixed2(halfLambertNum, halfLambertNum)).rgb; float3 halfA = normalize(normalize(i.viewDir) + normalize(i.lightDir)); fixed3 specularColor = _LightColor0.rgb * _SpecularColor.rgb * pow(max(0, dot(tangentNormal, halfA)), _SpecularNum); fixed3 color = UNITY_LIGHTMODEL_AMBIENT.rgb * albedo + diffuseColor + specularColor;
return fixed4(color.rgb, 1); }
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完整 Shader 代码如下:
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| Shader "TeachShader/Lesson54" { Properties { _MainColor("MainColor", Color) = (1, 1, 1, 1) _MainTex("MainTex", 2D) = ""{} _BumpMap("BumpMap", 2D) = ""{} _BumpScale("BumpScale", Range(0, 1)) = 1 _RampTex("_RampTex", 2D) = ""{} _SpecularColor("SpecularColor", Color) = (1, 1, 1, 1) _SpecularNum("SpecularNum", Range(0, 20)) = 18 } SubShader { Pass { Tags { "LightMode" = "ForwardBase" }
CGPROGRAM #pragma vertex vert #pragma fragment frag
#include "UnityCG.cginc" #include "Lighting.cginc"
struct v2f { float4 pos: SV_POSITION; float4 uv: TEXCOORD0; float3 lightDir: TEXCOORD1; float3 viewDir: TEXCOORD2; };
float4 _MainColor; sampler2D _MainTex; float4 _MainTex_ST; sampler2D _BumpMap; float4 _BumpMap_ST; sampler2D _RampTex; float4 _RampTex_ST; float _BumpScale; float4 _SpecularColor; fixed _SpecularNum;
v2f vert (appdata_full v) { v2f data; data.pos = UnityObjectToClipPos(v.vertex); data.uv.xy = v.texcoord.xy * _MainTex_ST.xy + _MainTex_ST.zw; data.uv.zw = v.texcoord.xy * _BumpMap_ST.xy + _BumpMap_ST.zw;
float3 binormal = cross(normalize(v.tangent), normalize(v.normal)) * v.tangent.w; float3x3 rotation = float3x3( v.tangent.xyz, binormal, v.normal ); data.lightDir = mul(rotation, ObjSpaceLightDir(v.vertex)); data.viewDir = mul(rotation, ObjSpaceViewDir(v.vertex));
return data; }
fixed4 frag (v2f i) : SV_Target { float4 packedNormal = tex2D(_BumpMap, i.uv.zw); float3 tangentNormal = UnpackNormal(packedNormal); tangentNormal.xy *= _BumpScale; tangentNormal.z = sqrt(1.0 - saturate(dot(tangentNormal.xy, tangentNormal.xy)));
fixed3 albedo = tex2D(_MainTex, i.uv.xy).rgb * _MainColor.rgb;
fixed halfLambertNum = dot(tangentNormal, normalize(i.lightDir)) * 0.5 + 0.5; fixed3 diffuseColor = _LightColor0.rgb * albedo.rgb * tex2D(_RampTex, fixed2(halfLambertNum, halfLambertNum)).rgb; float3 halfA = normalize(normalize(i.viewDir) + normalize(i.lightDir)); fixed3 specularColor = _LightColor0.rgb * _SpecularColor.rgb * pow(max(0, dot(tangentNormal, halfA)), _SpecularNum); fixed3 color = UNITY_LIGHTMODEL_AMBIENT.rgb * albedo + diffuseColor + specularColor;
return fixed4(color.rgb, 1); } ENDCG } } }
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显示效果(左侧直接使用BlinnPhong光照模型,右侧在BlinnPhong光照模型的基础上半兰伯特光照计算漫反射并使用渐变贴图):
可见,左侧的明暗变化更平滑,较为拟真,而右侧更明暗界线分明一些,更加卡通化