第十二章 亮度 饱和度 对比度

使用C#脚本 挂载在摄像机上

PostEffectsBase.cs

using UnityEngine;
using System.Collections;

[ExecuteInEditMode]
[RequireComponent (typeof(Camera))]
public class PostEffectsBase : MonoBehaviour {

    // Called when start
    protected void CheckResources() {
        bool isSupported = CheckSupport();
        
        if (isSupported == false) {
            NotSupported();
        }
    }

    // Called in CheckResources to check support on this platform
    protected bool CheckSupport() {
        if (SystemInfo.supportsImageEffects == false || SystemInfo.supportsRenderTextures == false) {
            Debug.LogWarning("This platform does not support image effects or render textures.");
            return false;
        }
        
        return true;
    }

    // Called when the platform doesn't support this effect
    protected void NotSupported() {
        enabled = false;
    }
    
    protected void Start() {
        CheckResources();
    }

    // Called when need to create the material used by this effect
    protected Material CheckShaderAndCreateMaterial(Shader shader, Material material) {
        if (shader == null) {
            return null;
        }
        
        if (shader.isSupported && material && material.shader == shader)
            return material;
        
        if (!shader.isSupported) {
            return null;
        }
        else {
            material = new Material(shader);
            material.hideFlags = HideFlags.DontSave;
            if (material)
                return material;
            else 
                return null;
        }
    }
}

BrightnessSaturationAndContrast.cs

using UnityEngine;
using System.Collections;

public class BrightnessSaturationAndContrast : PostEffectsBase {

    public Shader briSatConShader;
    private Material briSatConMaterial;
    public Material material {  
        get {
            briSatConMaterial = CheckShaderAndCreateMaterial(briSatConShader, briSatConMaterial);
            return briSatConMaterial;
        }  
    }

    [Range(0.0f, 3.0f)]
    public float brightness = 1.0f;

    [Range(0.0f, 3.0f)]
    public float saturation = 1.0f;

    [Range(0.0f, 3.0f)]
    public float contrast = 1.0f;

    void OnRenderImage(RenderTexture src, RenderTexture dest) {
        if (material != null) {
            material.SetFloat("_Brightness", brightness);
            material.SetFloat("_Saturation", saturation);
            material.SetFloat("_Contrast", contrast);

            Graphics.Blit(src, dest, material);
        } else {
            Graphics.Blit(src, dest);
        }
    }
}

内置渲染管线

Shader "SunY/C12-BrightnessSaturationAndContrast"
{
    Properties
    {
        _MainTex("Main Tex", 2D) = "white"{}
        _Brightness("Brightness", float) = 1
        _Saturation("Saturation", float) = 1
        _Contrast("Contrast", float) = 1
    }

    SubShader
    {
        Pass
        {
            ZTest Always
            Cull Off
            ZWrite Off

            CGPROGRAM

            #include "UnityCG.cginc"

            #pragma vertex vert
            #pragma fragment frag

            sampler2D _MainTex;
            float _Brightness;
            float _Saturation;
            float _Contrast;

            struct v2f
            {
                float4 pos : SV_POSITION;
                float2 uv : TEXCOORD0;
            };

            v2f vert(appdata_img v)
            {
                v2f o;

                o.pos = UnityObjectToClipPos(v.vertex);
                o.uv = v.texcoord;

                return o;
            }

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

                // 调整亮度
                fixed3 finalColor = renderTex.rgb * _Brightness;

                // 调整饱和度
                fixed luminance = 0.2125 * renderTex.r + 0.7154 * renderTex.g + 0.0721 * renderTex.b;
                fixed3 luminanceColor = fixed3(luminance, luminance, luminance);
                finalColor = lerp(finalColor, luminanceColor, _Saturation);

                // 调整对比度
                fixed3 avgColor = fixed3(0.5, 0.5, 0.5);
                finalColor = lerp(avgColor, finalColor, _Contrast);

                return fixed4(finalColor, renderTex.a);
            }

            ENDCG
        }
    }

    FallBack Off
}

URP不再支持这种方式后处理

改由Post-process Volume框架

在场景中添加挂载Volume组件的空物体，然后在上面添加各种预置好的后效组件

示例