popo

unity-shader-tutorial-fog

Posted on Edited on

buildin效果图

urp效果图

Fog.shader

Fog.shader
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
Shader "HHF/Tutorial/Fog"
{
    Properties
    {
        _MainTex("Texture", 2D) = "white" {}
        [KeywordEnum(Manual, Build)]_CalcMode("CalcMode",int) = 0
    }

    SubShader 
    {
        Tags { "RenderPipeline"="UniversalPipeline" }

        Pass
        {
            HLSLPROGRAM
            #pragma prefer_hlslcc gles
            #pragma exclude_renderers d3d11_9x
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile_fog
            #pragma shader_feature _CALCMODE_MANUAL _CALCMODE_BUILD
            
            #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/ShaderGraphFunctions.hlsl"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };
            
            struct v2f
            {
                float4 positionCS : SV_Position;
                float2 uv:TEXCOORD;

                #if _CALCMODE_MANUAL
                    // 自定义雾效插值器
                    float fogFactor : TEXCOORD1;  
                #endif // _CALCMODE_MANUAL 

                #if _CALCMODE_BUILD
                    float fogCoord  : TEXCOORD1;
                #endif // _CALCMODE_BUILD
            };

            CBUFFER_START(UnityPerMaterial)
            float4 _MainTex_ST;
            CBUFFER_END

            TEXTURE2D (_MainTex);SAMPLER(sampler_MainTex);

            v2f vert(appdata v)
            {
                v2f o = (v2f)0;
                float3 worldPos = TransformObjectToWorld(v.vertex.xyz);
                o.positionCS = TransformWorldToHClip(worldPos);
                o.uv = TRANSFORM_TEX(v.uv,_MainTex);

                #if _CALCMODE_MANUAL
                    // 手动计算雾效插值器的值
                    float z = length(_WorldSpaceCameraPos - worldPos);
                    #if defined(FOG_LINEAR)
                        // (end-z)/(end-start) = z *(-1/(end-start)) +(end/(end-start))
                        o.fogFactor = z * unity_FogParams.z + unity_FogParams.w;
                    #elif defined(FOG_EXP)
                        // exp2(-density *z)
                        o.fogFactor = exp2(-unity_FogParams.y * z);
                    #elif defined(FOG_EXP2)
                        // exp2(-(density*z)^2)
                        float density = unity_FogParams.x * z;
                        o.fogFactor = exp2(-density * density);
                    #endif
                #endif // _CALCMODE_MANUAL

                #if _CALCMODE_BUILD
                    o.fogCoord = ComputeFogFactor(o.positionCS.z);
                #endif // _CALCMODE_BUILD

                return o;
            }

            half4 frag(v2f i) : SV_TARGET 
            {    
                half4 c;

                half4 mainTex = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.uv);
                c = mainTex;

                #if _CALCMODE_MANUAL
                    #if defined(FOG_LINEAR) || defined(FOG_EXP) ||defined(FOG_EXP2)
                        c *= lerp(unity_FogColor, c,i.fogFactor);
                    #endif
                #endif // _CALCMODE_MANUAL

                #if _CALCMODE_BUILD
                    c.rgb = MixFog(c.rgb, i.fogCoord);
                #endif // _CALCMODE_BUILD

                return c;
            }

            ENDHLSL
        }   
    }

    SubShader
    {
        Tags { "RenderType"="Opaque" }

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile_fog
            #pragma shader_feature _CALCMODE_MANUAL _CALCMODE_BUILD

            #include "UnityCG.cginc"

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

            struct v2f
            {
                float4 positionCS : SV_POSITION;
                float2 uv : TEXCOORD0;

                #if _CALCMODE_MANUAL
                    float fogFactor : TEXCOORD1;     // 自定义雾效插值器
                #endif // _CALCMODE_MANUAL

                #if _CALCMODE_BUILD
                    // 相当于是在雾效开启时定义一个float类型的变量fogCoord
                    UNITY_FOG_COORDS(1)
                #endif // _CALCMODE_BUILD
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            v2f vert (appdata v)
            {
                v2f o = (v2f)0;
                float3 worldPos = mul(unity_ObjectToWorld, v.vertex);
                o.positionCS =  UnityObjectToClipPos(v.vertex); // mul(UNITY_MATRIX_VP, worldPos);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
              
                #if _CALCMODE_MANUAL
                    // 手动计算雾效插值器的值
                    float z = length(_WorldSpaceCameraPos - worldPos);
                    #if defined(FOG_LINEAR)
                        // (end-z)/(end-start) = z *(-1/(end-start)) +(end/(end-start))
                        o.fogFactor = z * unity_FogParams.z + unity_FogParams.w;
                    #elif defined(FOG_EXP)
                        // exp2(-density *z)
                        o.fogFactor = exp2(-unity_FogParams.y * z);
                    #elif defined(FOG_EXP2)
                        // exp2(-(density*z)^2)
                        float density = unity_FogParams.x * z;
                        o.fogFactor = exp2(-density * density);
                    #endif
                #endif // _CALCMODE_MANUAL

                #if _CALCMODE_BUILD
                    UNITY_TRANSFER_FOG(o, o.positionCS);
                #endif // _CALCMODE_BUILD

                return o;
            }

            fixed4 frag(v2f i) : SV_Target
            {
                fixed4 c = 0;
                fixed4 mainTex = tex2D(_MainTex, i.uv);
                c = mainTex;

                #if _CALCMODE_MANUAL
                    #if defined(FOG_LINEAR) || defined(FOG_EXP) ||defined(FOG_EXP2)
                        c *= lerp(unity_FogColor, c,i.fogFactor);
                    #endif
                #endif // _CALCMODE_MANUAL

                #if _CALCMODE_BUILD
                   UNITY_APPLY_FOG(i.fogCoord, c);
                #endif // _CALCMODE_BUILD

                return c;
            }
            ENDCG
        }
    }
}