Unity Shader 学习笔记(十四)使用屏幕特效实现亮度饱和度和对比度

Unity Shader 学习笔记(十四)使用屏幕特效实现亮度饱和度和对比度

1.创建一个场景
2.场景中随便添加一些GameObject
3,添加方向光源
4.创建BSC_Effect.shader着色器

Shader "Custom/BSC_Effect"
{
Properties
{
_MainTex ("Base (RGB)", 2D) = "white" {}
_BrightnessAmount ("Brightness Amount", Range(0.0, 1)) = 1.0
_satAmount ("Saturation Amount", Range(0.0, 1)) = 1.0
_conAmount ("Contrast Amount", Range(0.0, 1)) = 1.0
}

SubShader
{
Pass
{
CGPROGRAM
#pragma vertex vert_img
#pragma fragment frag
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"

uniform sampler2D _MainTex;
fixed _BrightnessAmount;
fixed _satAmount;
fixed _conAmount;

float3 ContrastSaturationBrightness(float3 color, float brt, float sat, float con)
{
// Increase or decrease theese values to
//adjust r, g and b color channels seperately
float AvgLumR = 0.5;
float AvgLumG = 0.5;
float AvgLumB = 0.5;

//Luminance coefficients for getting lumoinance from the image
float3 LuminanceCoeff = float3(0.2125, 0.7154, 0.0721);

//Operation for brightness
float3 AvgLumin = float3(AvgLumR, AvgLumG, AvgLumB);
float3 brtColor = color * brt;
float intensityf = dot(brtColor, LuminanceCoeff);
float3 intensity = float3(intensityf, intensityf, intensityf);

//Operation for Saturation
float3 satColor = lerp(intensity, brtColor, sat);

//Operation for Contrast
float3 conColor = lerp(AvgLumin, satColor, con);
return conColor;
}

fixed4 frag(v2f_img i) : COLOR
{
//Get the colors from the RenderTexture and the uv's
//from the v2f_img struct
fixed4 renderTex = tex2D(_MainTex, i.uv);

//Apply the Brughtness, saturation, contrast operations
renderTex.rgb = ContrastSaturationBrightness(renderTex.rgb,
_BrightnessAmount,
_satAmount,
_conAmount);

return renderTex;
}

ENDCG
}
}
FallBack off
}

5.创建BSC_ImageEffect.cs脚本,并将该脚本绑定到摄像机

using UnityEngine;
using System.Collections;

[ExecuteInEditMode]
public class BSC_ImageEffect : MonoBehaviour
{

#region Variables
public Shader curShader;
//当前亮度
public float brightnessAmount = 1.0f;
//当前饱和度
public float saturationAmount = 1.0f;
//当前对比度
public float contrastAmount = 1.0f;
private Material curMaterial;
#endregion

#region Properties
Material material
{
get
{
if(curMaterial == null)
{
curMaterial = new Material(curShader);
curMaterial.hideFlags = HideFlags.HideAndDontSave;
}
return curMaterial;
}
}
#endregion

void Start()
{
if(!SystemInfo.supportsImageEffects)
{
enabled = false;
return;
}

if(!curShader && !curShader.isSupported)
{
enabled = false;
}
}

void OnRenderImage(RenderTexture sourceTexture, RenderTexture destTexture)
{
if(curShader != null)
{
material.SetFloat("_BrightnessAmount", brightnessAmount);
material.SetFloat("_satAmount", saturationAmount);
material.SetFloat("_conAmount", contrastAmount);

Graphics.Blit(sourceTexture, destTexture, material);
}
else
{
Graphics.Blit(sourceTexture, destTexture);
}
}

void Update()
{
//设置亮度
brightnessAmount = Mathf.Clamp(brightnessAmount, 0.0f, 2.0f);
//设置饱和度
saturationAmount = Mathf.Clamp(saturationAmount, 0.0f, 2.0f);
//设置对比度
contrastAmount = Mathf.Clamp(contrastAmount, 0.0f, 3.0f);
}

void OnDisable()
{
if(curMaterial)
{
DestroyImmediate(curMaterial);
}
}
}

6,摄像机的Inspector面板中为 Cur Shader赋值为刚才创建的shader

7.分别调节 brightnessAmount , saturationAmount , contrastAmount 的值来修改亮度,饱和度和对比度