《Unity Shader 入门精要》从Bulit-in 到URP （HLSL）Chapter15.3-基于噪声纹理的全局雾效

eyou121 发表于 2024-7-15 18:02

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 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader ”Unity Shaders Book/Chapter 15/Fog With Noise” {
Properties {
_MainTex (”Base (RGB)”, 2D) = ”white” {}
_FogDensity (”Fog Density”, Float) = 1.0
_FogColor (”Fog Color”, Color) = (1, 1, 1, 1)
_FogStart (”Fog Start”, Float) = 0.0
_FogEnd (”Fog End”, Float) = 1.0
_NoiseTex (”Noise Texture”, 2D) = ”white” {}
_FogXSpeed (”Fog Horizontal Speed”, Float) = 0.1
_FogYSpeed (”Fog Vertical Speed”, Float) = 0.1
_NoiseAmount (”Noise Amount”, Float) = 1
}
SubShader {
CGINCLUDE

#include ”UnityCG.cginc”

float4x4 _FrustumCornersRay;

sampler2D _MainTex;
half4 _MainTex_TexelSize;
sampler2D _CameraDepthTexture;
half _FogDensity;
fixed4 _FogColor;
float _FogStart;
float _FogEnd;
sampler2D _NoiseTex;
half _FogXSpeed;
half _FogYSpeed;
half _NoiseAmount;

struct v2f {
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float2 uv_depth : TEXCOORD1;
float4 interpolatedRay : TEXCOORD2;
};

v2f vert(appdata_img v) {
v2f o;
o.pos = UnityObjectToClipPos(v.vertex);

o.uv = v.texcoord;
o.uv_depth = v.texcoord;

#if UNITY_UV_STARTS_AT_TOP
if (_MainTex_TexelSize.y < 0)
o.uv_depth.y = 1 - o.uv_depth.y;
#endif

int index = 0;
if (v.texcoord.x < 0.5 && v.texcoord.y < 0.5) {
index = 0;
} else if (v.texcoord.x > 0.5 && v.texcoord.y < 0.5) {
index = 1;
} else if (v.texcoord.x > 0.5 && v.texcoord.y > 0.5) {
index = 2;
} else {
index = 3;
}
#if UNITY_UV_STARTS_AT_TOP
if (_MainTex_TexelSize.y < 0)
index = 3 - index;
#endif

o.interpolatedRay = _FrustumCornersRay;

return o;
}

fixed4 frag(v2f i) : SV_Target {
float linearDepth = LinearEyeDepth(SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, i.uv_depth));
float3 worldPos = _WorldSpaceCameraPos + linearDepth * i.interpolatedRay.xyz;

float2 speed = _Time.y * float2(_FogXSpeed, _FogYSpeed);
float noise = (tex2D(_NoiseTex, i.uv + speed).r - 0.5) * _NoiseAmount;

float fogDensity = (_FogEnd - worldPos.y) / (_FogEnd - _FogStart);
fogDensity = saturate(fogDensity * _FogDensity * (1 + noise));

fixed4 finalColor = tex2D(_MainTex, i.uv);
finalColor.rgb = lerp(finalColor.rgb, _FogColor.rgb, fogDensity);

return finalColor;
}

ENDCG

Pass {
CGPROGRAM

#pragma vertex vert
#pragma fragment frag

ENDCG
}
}
FallBack Off
}

URP版：

Unity项目源码：
Shader ”Unlit/Chapter15-FogWithNoise”
{
Properties {
_MainTex (”Base (RGB)”, 2D) = ”white” {}
_FogDensity (”Fog Density”, Float) = 1.0
_FogColor (”Fog Color”, Color) = (1, 1, 1, 1)
_FogStart (”Fog Start”, Float) = 0.0
_FogEnd (”Fog End”, Float) = 1.0
_NoiseTex (”Noise Texture”, 2D) = ”white” {}
_FogXSpeed (”Fog Horizontal Speed”, Float) = 0.1
_FogYSpeed (”Fog Vertical Speed”, Float) = 0.1
_NoiseAmount (”Noise Amount”, Float) = 1
}
SubShader {
   Tags {”RenderPipeline” = ”UniversalPipeline”}
HLSLINCLUDE

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

   CBUFFER_START(UnityPerMaterial)
         half4 _MainTex_TexelSize;
         half _FogDensity;
         half4 _FogColor;
         float _FogStart;
         float _FogEnd;
         half _FogXSpeed;
         half _FogYSpeed;
         half _NoiseAmount;
         float4x4 _FrustumCornersRay;
   CBUFFER_END

TEXTURE2D(_MainTex);                         SAMPLER(sampler_MainTex);
         TEXTURE2D(_CameraDepthTexture);             SAMPLER(sampler_CameraDepthTexture);
         TEXTURE2D(_NoiseTex);                      SAMPLER(sampler_NoiseTex);

   struct appdata{
         float4 vertex : POSITION;
         float2 texcoord : TEXCOORD0;
   };

struct v2f {
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float2 uv_depth : TEXCOORD1;
float4 interpolatedRay : TEXCOORD2;
};

v2f vert(appdata v) {
v2f o;
o.pos = TransformObjectToHClip(v.vertex);

o.uv = v.texcoord;
o.uv_depth = v.texcoord;

#if UNITY_UV_STARTS_AT_TOP
if (_MainTex_TexelSize.y < 0)
o.uv_depth.y = 1 - o.uv_depth.y;
#endif

int index = 0;
if (v.texcoord.x < 0.5 && v.texcoord.y < 0.5) {
index = 0;
} else if (v.texcoord.x > 0.5 && v.texcoord.y < 0.5) {
index = 1;
} else if (v.texcoord.x > 0.5 && v.texcoord.y > 0.5) {
index = 2;
} else {
index = 3;
}
#if UNITY_UV_STARTS_AT_TOP
if (_MainTex_TexelSize.y < 0)
index = 3 - index;
#endif

o.interpolatedRay = _FrustumCornersRay;

return o;
}

half4 frag(v2f i) : SV_Target {
float linearDepth = LinearEyeDepth(SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, sampler_CameraDepthTexture, i.uv_depth), _ZBufferParams);
float3 worldPos = _WorldSpaceCameraPos + linearDepth * i.interpolatedRay.xyz;

float2 speed = _Time.y * float2(_FogXSpeed, _FogYSpeed);
float noise = (SAMPLE_TEXTURE2D(_NoiseTex, sampler_NoiseTex, i.uv + speed).r - 0.5) * _NoiseAmount;

float fogDensity = (_FogEnd - worldPos.y) / (_FogEnd - _FogStart);
fogDensity = saturate(fogDensity * _FogDensity * (1 + noise));

half4 finalColor = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.uv);
finalColor.rgb = lerp(finalColor.rgb, _FogColor.rgb, fogDensity);

return finalColor;
}

ENDHLSL

Pass {
HLSLPROGRAM

#pragma vertex vert
#pragma fragment frag

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

如有收获，请留下“存眷”和“附和”

页: [1]

Unity开发者联盟's Archiver

《Unity Shader 入门精要》从Bulit-in 到URP （HLSL）Chapter15.3-基于噪声纹理的全局雾效