• Unity shader学习之屏幕后期处理效果之高度雾,重建world pos方法2


    这里使用一种更高效地从深度纹理中重建世界坐标的方法。

    首先计算摄像机的视锥体的四条射线向量进行线性插值,插值后的值便是该像素在世界空间坐标下到摄像机的方向。

    然后通过与深度值相乘即可得到摄像机位置到该像素的向量,加上摄像机的位置则是该像素在世界空间中的位置。

    转载请注明出处:https://www.cnblogs.com/jietian331/p/9443343.html

    c#代码:

     1 using UnityEngine;
     2 
     3 public class HighFog2 : PostEffectRenderer
     4 {
     5     [SerializeField]
     6     Color m_fogColor = Color.white;
     7     [Range(0f, 1f)]
     8     [SerializeField]
     9     float m_fogDensity = 0.9f;
    10     [SerializeField]
    11     float m_fogPosY = 0.1f;
    12     [SerializeField]
    13     float m_fogDisappearHeight = 8;
    14 
    15 
    16     protected override string ShaderName
    17     {
    18         get { return "Custom/Study/HighFog2"; }
    19     }
    20 
    21     protected override void OnRenderImage(RenderTexture src, RenderTexture dest)
    22     {
    23         float fov = base.SelfCamera.fieldOfView;
    24         float near = base.SelfCamera.nearClipPlane;
    25         Transform camT = base.SelfCamera.transform;
    26 
    27         float halfFOV = fov * Mathf.PI / 360f;
    28         float toTopDis = near * Mathf.Tan(halfFOV);
    29         float toRightDis = toTopDis * (Screen.width / Screen.height);
    30         Vector3 toTop = camT.up * toTopDis;
    31         Vector3 toRight = camT.right * toRightDis;
    32         Vector3 toCenter = camT.forward * near;
    33         Vector3 topLeft = (toCenter + toTop - toRight) / near;
    34         Vector3 topRight = (toCenter + toTop + toRight) / near;
    35         Vector3 bottomLeft = (toCenter - toTop - toRight) / near;
    36         Vector3 bottomRight = (toCenter - toTop - toRight) / near;
    37 
    38         Matrix4x4 matrix = Matrix4x4.identity;
    39         matrix.SetRow(0, bottomLeft);
    40         matrix.SetRow(1, bottomRight);
    41         matrix.SetRow(2, topLeft);
    42         matrix.SetRow(3, topRight);
    43 
    44         base.Mat.SetMatrix("_CameraRays", matrix);
    45         base.Mat.SetColor("_FogColor", m_fogColor);
    46         base.Mat.SetFloat("_FogDensity", m_fogDensity);
    47         base.Mat.SetFloat("_FogPosY", m_fogPosY);
    48         base.Mat.SetFloat("_FogDisappearHeight", m_fogDisappearHeight);
    49         base.OnRenderImage(src, dest);
    50     }
    51 }
    View Code

    shader:

      1 Shader "Custom/Study/HighFog2"
      2 {
      3     Properties
      4     {
      5         _MainTex ("Texture", 2D) = "white" {}
      6     }
      7 
      8     SubShader
      9     {
     10         Pass
     11         {
     12             ZTest Always
     13             ZWrite Off
     14             Cull Off
     15 
     16             CGPROGRAM
     17             #pragma vertex vert
     18             #pragma fragment frag
     19             
     20             #include "UnityCG.cginc"
     21 
     22             struct appdata
     23             {
     24                 float4 vertex : POSITION;
     25                 float2 uv : TEXCOORD0;
     26             };
     27 
     28             struct v2f
     29             {
     30                 float2 uv : TEXCOORD0;
     31                 float4 vertex : SV_POSITION;
     32                 float3 ray : TEXCOORD1;
     33             };
     34 
     35             sampler2D _MainTex;
     36             sampler2D _CameraDepthTexture;
     37             uniform float4x4 _CameraRays;
     38             uniform float4 _FogColor;
     39             uniform float _FogDensity;
     40             uniform float _FogPosY;
     41             uniform float _FogDisappearHeight;
     42 
     43             v2f vert (appdata v)
     44             {
     45                 v2f o;
     46                 o.vertex = UnityObjectToClipPos(v.vertex);
     47                 o.uv = v.uv;
     48 
     49                 int index;
     50                 if(v.vertex.x < 0.5 && v.vertex.y < 0.5)
     51                 {
     52                     index = 0;
     53                 }
     54                 else if(v.vertex.x > 0.5 && v.vertex.y < 0.5)
     55                 {
     56                     index = 1;
     57                 }
     58                 else if(v.vertex.x > 0.5 && v.vertex.y > 0.5)
     59                 {
     60                     index = 2;
     61                 }
     62                 else
     63                 {
     64                     index = 3;
     65                 }
     66                 o.ray = _CameraRays[index].xyz;
     67 
     68                 return o;
     69             }
     70             
     71             fixed4 frag (v2f i) : SV_Target
     72             {
     73                 fixed4 col = tex2D(_MainTex, i.uv);
     74                 
     75                 float d = LinearEyeDepth(SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, i.uv));
     76                 float3 worldPos = _WorldSpaceCameraPos + i.ray * d;
     77 
     78                 float fogWeight;
     79                 if(worldPos.y < _FogPosY)
     80                 {
     81                     fogWeight = 1;
     82                 }
     83                 else if(worldPos.y > _FogPosY + _FogDisappearHeight)
     84                 {
     85                     fogWeight = 0;
     86                 }
     87                 else
     88                 {
     89                     fogWeight = 1 - (worldPos.y - _FogPosY) / _FogDisappearHeight;
     90                 }
     91 
     92                 return lerp(col, _FogColor, fogWeight * _FogDensity);
     93             }
     94 
     95             ENDCG
     96         }
     97     }
     98 
     99     Fallback Off
    100 }
    View Code

    效果图如下:

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  • 原文地址:https://www.cnblogs.com/jietian331/p/9443343.html
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