URP标准光照模型
该节对之前学习的纹理、阴影、透明效果、多光源处理进行了一个汇总，并对代码进行了一定的优化。
效果图
思路
在Shader中设置了三个Bool变量和对应的关键字，用于分别控制透明度裁剪功能、法线纹理功能和多光源计算功能的开启和关闭；这一来达到一个Shader多次利用。
使用到的语法
-
通过传入对象空间下坐标，返回一个结构体，该结构体持有不同空间下转换后的坐标
VertexPositionInputs positionInputs = GetVertexPositionInputs(v.positionOS.xyz);//"Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl" VertexPositionInputs GetVertexPositionInputs(float3 positionOS) { VertexPositionInputs input; input.positionWS = TransformObjectToWorld(positionOS); input.positionVS = TransformWorldToView(input.positionWS); input.positionCS = TransformWorldToHClip(input.positionWS); float4 ndc = input.positionCS * 0.5f; input.positionNDC.xy = float2(ndc.x, ndc.y * _ProjectionParams.x) + ndc.w; input.positionNDC.zw = input.positionCS.zw; return input; } -
通过传入对象空间下的法线与切线，返回世界空间下切线相关的向量
VertexNormalInputs normalInput = GetVertexNormalInputs(v.normalOS, v.tangentOS);//"Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl" VertexNormalInputs GetVertexNormalInputs(float3 normalOS) { VertexNormalInputs tbn; tbn.tangentWS = real3(1.0, 0.0, 0.0); tbn.bitangentWS = real3(0.0, 1.0, 0.0); tbn.normalWS = TransformObjectToWorldNormal(normalOS); return tbn; } VertexNormalInputs GetVertexNormalInputs(float3 normalOS, float4 tangentOS) { VertexNormalInputs tbn; // mikkts space compliant. only normalize when extracting normal at frag. real sign = tangentOS.w * GetOddNegativeScale(); tbn.normalWS = TransformObjectToWorldNormal(normalOS); tbn.tangentWS = TransformObjectToWorldDir(tangentOS.xyz); tbn.bitangentWS = cross(tbn.normalWS, tbn.tangentWS) * sign; return tbn; }
完整代码
Shader "URP/MultiLightShadowNormalMapAlphaTest"
{
Properties
{
// 基础纹理
[MainColor] _BaseColor ("Color", Color) = (0.5, 0.5, 0.5, 1)
[MainTexture] _BaseMap ("Albedo", 2D) = "white" { }
// 透明度裁剪
[Toggle(_ALPHATEST_ON)] _EnableAlphaTest ("Alpha Cutoff", Float) = 0.0
_Cutoff ("Alpha Cutoff", Range(0.0, 1.0)) = 0.5
// 法线贴图
[Toggle(_NORMALMAP)] _EnableBumpMap ("Bump Map", Float) = 0.0
_BumpScale ("Normal Scale", Float) = 1.0
_BumpMap ("Normal Map", 2D) = "bump" { }
// 漫反射叠加颜色
_Diffuse ("Diffuse", Color) = (1, 1, 1, 1)
// 高光反射叠加颜色
_Specular ("Specular", Color) = (1, 1, 1, 1)
// 高光系数
_Gloss ("Gloss", Range(8.0, 256)) = 20
// 是否计算多光源
[Toggle(_AdditionalLights)] _AddLights ("AddLights", Float) = 1
}
SubShader
{
Tags { "RenderType" = "Opaque" "RenderPipeline" = "UniversalPipeline" }
HLSLINCLUDE
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
CBUFFER_START(UnityPerMaterial)
float4 _BaseColor;
float4 _BaseMap_ST;
half _Cutoff;
float4 _BumpMap_ST;
float _BumpScale;
float4 _Diffuse;
float4 _Specular;
float _Gloss;
CBUFFER_END
ENDHLSL
Pass
{
Tags { "LightMode" = "UniversalForward" }
Cull Off
HLSLPROGRAM
// 设置关键字
#pragma shader_feature _NORMALMAP
#pragma shader_feature _ALPHATEST_ON
#pragma shader_feature _AdditionalLights
// 接收阴影所需关键字
#pragma multi_compile _ _MAIN_LIGHT_SHADOWS
#pragma multi_compile _ _MAIN_LIGHT_SHADOWS_CASCADE
#pragma multi_compile _ _ADDITIONAL_LIGHTS_VERTEX _ADDITIONAL_LIGHTS
#pragma multi_compile _ _SHADOWS_SOFT
#pragma vertex vert
#pragma fragment frag
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/CommonMaterial.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
TEXTURE2D(_BaseMap);
SAMPLER(sampler_BaseMap);
TEXTURE2D(_BumpMap);
SAMPLER(sampler_BumpMap);
struct Attributes
{
float4 positionOS: POSITION;//位置
float3 normalOS: NORMAL;//法线
float4 tangentOS: TANGENT;//切线
float2 texcoord: TEXCOORD0;//纹理坐标
};
struct Varyings
{
float4 positionCS: SV_POSITION;
float2 uv: TEXCOORD0;
float3 positionWS: TEXCOORD1;
#ifdef _NORMALMAP//如果使用了法线贴图
float4 normalWS: TEXCOORD3; // xyz: normal, w: viewDir.x
float4 tangentWS: TEXCOORD4; // xyz: tangent, w: viewDir.y
float4 bitangentWS: TEXCOORD5; // xyz: bitangent, w: viewDir.z
#else
float3 normalWS: TEXCOORD3;
float3 viewDirWS: TEXCOORD4;
#endif
};
Varyings vert(Attributes v)
{
Varyings o;
// 获取不同空间下坐标信息
VertexPositionInputs positionInputs = GetVertexPositionInputs(v.positionOS.xyz);
o.positionCS = positionInputs.positionCS;
o.positionWS = positionInputs.positionWS;
o.uv = TRANSFORM_TEX(v.texcoord, _BaseMap);
// 获取世界空间下法线相关向量
VertexNormalInputs normalInput = GetVertexNormalInputs(v.normalOS, v.tangentOS);
// 视角方向
half3 viewDirWS = GetCameraPositionWS() - positionInputs.positionWS;
#ifdef _NORMALMAP// 如果使用了法线贴图
o.normalWS = half4(normalInput.normalWS, viewDirWS.x);
o.tangentWS = half4(normalInput.tangentWS, viewDirWS.y);
o.bitangentWS = half4(normalInput.bitangentWS, viewDirWS.z);
#else
o.normalWS = NormalizeNormalPerVertex(normalInput.normalWS);
o.viewDirWS = viewDirWS;
#endif
return o;
}
/// albedo：反射系数
/// lightColor：光源颜色
/// lightDirectionWS：世界空间下光线方向
/// lightAttenuation：光照衰减
/// normalWS：世界空间下法线
/// viewDirectionWS：世界空间下视角方向
half3 LightingBased(half3 albedo, half3 lightColor, half3 lightDirectionWS, half lightAttenuation, half3 normalWS, half3 viewDirectionWS)
{
// 兰伯特漫反射计算
half NdotL = saturate(dot(normalWS, lightDirectionWS));
half3 radiance = lightColor * (lightAttenuation * NdotL) * _Diffuse.rgb;
// BlinnPhong高光反射
half3 halfDir = normalize(lightDirectionWS + viewDirectionWS);
half3 specular = lightColor * pow(saturate(dot(normalWS, halfDir)), _Gloss) * _Specular.rgb;
return(radiance + specular) * albedo;
}
// 计算漫反射与高光
half3 LightingBased(half3 albedo, Light light, half3 normalWS, half3 viewDirectionWS)
{
// 注意light.distanceAttenuation * light.shadowAttenuation，这里已经将距离衰减与阴影衰减进行了计算
return LightingBased(albedo, light.color, light.direction, light.distanceAttenuation * light.shadowAttenuation, normalWS, viewDirectionWS);
}
half4 frag(Varyings i): SV_Target
{
half3 viewDirWS ;
half3 normalWS;
#ifdef _NORMALMAP// 是否使用法线纹理
viewDirWS = half3(i.normalWS.w, i.tangentWS.w, i.bitangentWS.w);
//可以使用该方法替代下面的法线纹理采样，但是需要引用函数库ShaderLibrary/SurfaceInput.hlsl
//half3 normalTS = SampleNormal(i.uv, TEXTURE2D_ARGS(_BumpMap, sampler_BumpMap), _BumpScale);
//or
half3 normalTS = UnpackNormalScale(SAMPLE_TEXTURE2D(_BumpMap, sampler_BumpMap, i.uv), _BumpScale);
normalWS = TransformTangentToWorld(normalTS, half3x3(i.tangentWS.xyz, i.bitangentWS.xyz, i.normalWS.xyz));
#else
viewDirWS = i.viewDirWS;
normalWS = i.normalWS;
#endif
normalWS = NormalizeNormalPerPixel(normalWS);
viewDirWS = SafeNormalize(viewDirWS);
//纹理采样
//可以使用该方法替代下面的纹理采集操作，但是需要引用函数库ShaderLibrary/SurfaceInput.hlsl
//half4 albedoAlpha = SampleAlbedoAlpha(i.uv, TEXTURE2D_ARGS(_BaseMap, sampler_BaseMap));
// or
half4 albedoAlpha = SAMPLE_TEXTURE2D(_BaseMap, sampler_BaseMap, i.uv);
// 透明度裁剪
//可以使用该方法替代下面的裁剪操作，但是需要引用函数库ShaderLibrary/SurfaceInput.hlsl
//half alpha = Alpha(albedoAlpha.a, _BaseColor, _Cutoff);
//or
#if defined(_ALPHATEST_ON)
clip(albedoAlpha.a - _Cutoff);
#endif
// 漫反射系数
//half3 albedo = albedoAlpha.rgb * _BaseColor.rgb;
// or
half3 albedo = SAMPLE_TEXTURE2D(_BaseMap, sampler_BaseMap, i.uv).rgb * _BaseColor.rgb;
// 获取阴影坐标
float4 shadowCoord = TransformWorldToShadowCoord(i.positionWS.xyz);
// 计算主光源与阴影
Light mainLight = GetMainLight(shadowCoord);
half3 diffuse = LightingBased(albedo, mainLight, normalWS, viewDirWS);
// 计算其他光源与阴影
// 需要将光源组件的ShadowType参数打开，并且将管线中的CastShadows勾选，副光源才会产生阴影
#ifdef _AdditionalLights
uint pixelLightCount = GetAdditionalLightsCount();
for (uint lightIndex = 0u; lightIndex < pixelLightCount; ++ lightIndex)
{
Light light = GetAdditionalLight(lightIndex, i.positionWS);
diffuse += LightingBased(albedo, light, normalWS, viewDirWS);
}
#endif
// 计算环境光
half3 ambient = SampleSH(normalWS) * albedo;
return half4(ambient + diffuse, 1.0);
}
ENDHLSL
}
// 计算阴影的Pass
Pass
{
Name "ShadowCaster"
Tags { "LightMode" = "ShadowCaster" }
Cull Off
ZWrite On
ZTest LEqual
HLSLPROGRAM
// 设置关键字
#pragma shader_feature _ALPHATEST_ON
#pragma vertex vert
#pragma fragment frag
#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/CommonMaterial.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl"
float3 _LightDirection;
struct Attributes
{
float4 positionOS: POSITION;
float3 normalOS: NORMAL;
float2 texcoord: TEXCOORD0;
};
struct Varyings
{
float2 uv: TEXCOORD0;
float4 positionCS: SV_POSITION;
};
TEXTURE2D(_BaseMap);
SAMPLER(sampler_BaseMap);
// 获取裁剪空间下的阴影坐标
float4 GetShadowPositionHClips(Attributes input)
{
float3 positionWS = TransformObjectToWorld(input.positionOS.xyz);
float3 normalWS = TransformObjectToWorldNormal(input.normalOS);
// 获取阴影专用裁剪空间下的坐标
float4 positionCS = TransformWorldToHClip(ApplyShadowBias(positionWS, normalWS, _LightDirection));
// 判断是否是在DirectX平台翻转过坐标
#if UNITY_REVERSED_Z
positionCS.z = min(positionCS.z, positionCS.w * UNITY_NEAR_CLIP_VALUE);
#else
positionCS.z = max(positionCS.z, positionCS.w * UNITY_NEAR_CLIP_VALUE);
#endif
return positionCS;
}
Varyings vert(Attributes input)
{
Varyings output;
output.uv = TRANSFORM_TEX(input.texcoord, _BaseMap);
output.positionCS = GetShadowPositionHClips(input);
return output;
}
half4 frag(Varyings input): SV_TARGET
{
//可以使用该方法替代下面的裁剪操作，但是需要引用函数库ShaderLibrary/SurfaceInput.hlsl
//Alpha(SampleAlbedoAlpha(input.uv, TEXTURE2D_ARGS(_BaseMap, sampler_BaseMap)).a, _BaseColor, _Cutoff);
//or
half4 albedoAlpha = SAMPLE_TEXTURE2D(_BaseMap, sampler_BaseMap, input.uv);
#if defined(_ALPHATEST_ON)
clip(albedoAlpha.a - _Cutoff);
#endif
return 0;
}
ENDHLSL
}
}
FallBack "Packages/com.unity.render-pipelines.universal/FallbackError"
}
