Unity shader学习之屏幕后期效果之调整屏幕亮度，饱和度，对比度

 1 using UnityEngine;
 2 
 3 [RequireComponent(typeof(Camera))]
 4 public abstract class PostEffectRenderer : GameBehaviour
 5 {
 6     protected abstract string ShaderName { get; }
 7 
 8     Material m_mat;
 9 
10     void Start()
11     {
12         if (!SystemInfo.supportsImageEffects)
13             NotSupport();
14     }
15 
16     protected virtual void OnRenderImage(RenderTexture src, RenderTexture dest)
17     {
18         Graphics.Blit(src, dest, Mat);
19     }
20 
21     protected void NotSupport()
22     {
23         enabled = false;
24     }
25 
26     protected Material Mat
27     {
28         get
29         {
30             if (!m_mat)
31             {
32                 Shader shader = Shader.Find(ShaderName);
33                 if (shader != null && shader.isSupported)
34                     m_mat = new Material(shader);
35                 else
36                     NotSupport();
37             }
38             return m_mat;
39         }
40     }
41 }

 1 using UnityEngine;
 2 
 3 public class ScreencolorsAdjuster : PostEffectRenderer
 4 {
 5     [SerializeField]
 6     float m_brightness = 1;
 7     [SerializeField]
 8     float m_saturation = 0;
 9     [SerializeField]
10     float m_contrast = 0;
11 
12     protected override void OnRenderImage(RenderTexture src, RenderTexture dest)
13     {
14         base.Mat.SetFloat("_Brightness", m_brightness);
15         base.Mat.SetFloat("_Saturation", m_saturation);
16         base.Mat.SetFloat("_Contrast", m_contrast);
17         base.OnRenderImage(src, dest);
18     }
19 
20     protected override string ShaderName
21     {
22         get { return "Custom/Screencolors Adjuster"; }
23     }
24 }

 1 Shader "Custom/Screencolors Adjuster"
 2 {
 3     Properties
 4     {
 5         _MainTex("Main Texture", 2D) = "white" {}
 6         _Brightness("Brightness", Float) = 1
 7         _Saturation("Saturation", Float) = 0
 8         _Contrast("Contrast", Float) = 0
 9     }
10 
11     SubShader
12     {
13         Pass
14         {
15             ZTest Always
16             ZWrite Off
17             Cull Off
18 
19             CGPROGRAM
20             #pragma vertex vert
21             #pragma fragment frag
22 
23             sampler2D _MainTex;
24             float _Brightness;
25             float _Saturation;
26             float _Contrast;
27 
28             struct appdata
29             {
30                 float4 vertex : POSITION;
31                 float2 uv : TEXCOORD0;
32             };
33 
34             struct v2f
35             {
36                 float4 pos : SV_POSITION;
37                 float2 uv : TEXCOORD0;
38             };
39 
40             v2f vert(appdata v)
41             {
42                 v2f o;
43                 o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
44                 o.uv = v.uv;
45 
46                 return o;
47             }
48 
49             fixed4 frag(v2f i) : SV_TARGET
50             {
51                 fixed4 tex = tex2D(_MainTex, i.uv);
52 
53                 fixed3 finalCol = tex.rgb * _Brightness;
54 
55                 fixed luminance = dot(fixed3(0.2125, 0.7154, 0.0721), tex.rgb);
56                 fixed3 luminanceCol = fixed3(luminance, luminance, luminance);
57                 finalCol = lerp(finalCol, luminanceCol, _Saturation);
58 
59                 fixed3 avgCol = fixed3(0.5, 0.5, 0.5);
60                 finalCol = lerp(finalCol, avgCol, _Contrast);
61 
62                 return fixed4(finalCol, tex.a);
63             }
64 
65             ENDCG
66         }
67     }
68 
69     Fallback Off
70 }