10.Gameplay and Screen Effects

老电影效果

Sepia tone 棕褐色调

通过叠加颜色获得

fixed lum = dot (fixed3(0.299, 0.587, 0.114), renderTex.rgb); 
fixed4 finalColor = lum + lerp(_SepiaColor, _SepiaColor + fixed4(0.1f,0.1f,0.1f,1.0f), _RandomValue); 
finalColor = pow(finalColor, _Contrast);

Vignette effect 晕影效果

也是通过叠加图片获得的

fixed4 vignetteTex = tex2D(_VignetteTex, i.uv);
finalColor = lerp(finalColor, finalColor * vignetteTex, _VignetteAmount);

Dust and scratches 脏迹和划痕

虽然更加复杂，但依旧是叠加图片获得的，只是增加了uv的滚动

half2 scratchesUV = half2(i.uv.x + (_RandomValue * _SinTime.z * _ScratchesXSpeed), i.uv.y + (_Time.x * _ScratchesYSpeed)); 
fixed4 scratchesTex = tex2D(_ScratchesTex, scratchesUV); 
finalColor.rgb *= lerp(scratchesTex, constantWhite, (_RandomValue)); 

half2 dustUV = half2(i.uv.x + (_RandomValue * (_SinTime.z * _dustXSpeed)), i.uv.y + (_RandomValue * 	(_SinTime.z * _dustYSpeed))); 
fixed4 dustTex = tex2D(_DustTex, dustUV); 
finalColor.rgb *= lerp(dustTex.rgb, constantWhite, (_RandomValue * _SinTime.z));

夜视效果

仍旧是图片叠加

   //失真算法，对当前UV值变换
   float2 barrelDistortion(float2 coord)  
    { 
        float2 h = coord.xy - float2(0.5, 0.5); 
        float r2 = h.x * h.x + h.y * h.y; 
        float f = 1.0 + r2 * (_distortion * sqrt(r2)); 
        return f * _scale * h + 0.5; 
    } 

    fixed4 frag(v2f_img i) : COLOR 
    { 
        //取失真后的uv值
        half2 distortedUV = barrelDistortion(i.uv); 
        
        //采样
        fixed4 renderTex = tex2D(_MainTex, distortedUV); 
        fixed4 vignetteTex = tex2D(_VignetteTex, i.uv); 

        //采样扫描线图片
        half2 scanLinesUV = half2(i.uv.x * _ScanLineTileAmount, i.uv.y * _ScanLineTileAmount); 
        fixed4 scanLineTex = tex2D(_ScanLineTex, scanLinesUV); 
        
        //采样噪声图片
        half2 noiseUV = half2(i.uv.x + (_RandomValue * _SinTime.z * _NoiseXSpeed), i.uv.y + (_Time.x * _NoiseYSpeed)); 
        fixed4 noiseTex = tex2D(_NoiseTex, noiseUV); 

        //叠加夜视颜色色调
        fixed lum = dot (fixed3(0.299, 0.587, 0.114), renderTex.rgb); 
        lum += _Brightness; 
        fixed4 finalColor = (lum *2) + _NightVisionColor; 

        //叠加在一起
        finalColor = pow(finalColor, _Contrast); 
        finalColor *= vignetteTex; 
        finalColor *= scanLineTex * noiseTex; 

        return finalColor; 
    }

11.Advanced Shading Techniques

使用UnityCG.cginc文件中的函数

文件位于Editor\Data\CGIncludes文件夹下
Luminance函数（在UnityCG.cginc中定义）：

函数定义（返回灰度值）：

inline half Luminance(half3 rgb)
{
return dot(rgb, unity_ColorSpaceLuminance.rgb);
}

其中，unity_ColorSpaceLuminance也在此文件中定义

#define unity_ColorSpaceLuminance half4(0.22, 0.707, 0.071, 0.0)
使用自定义的CGInclude文件（头文件）
1. 创建MyCGInclude.cginc文件
2. 在文件中实现函数
3. 在shader中使用#include “MyCGInclude.cginc”
4. 调用文件中的函数

毛皮着色器

首先新建一个pass，它将在顶点函数中创建一个稍大一些的模型（同时考虑了重力）

void vert (inout appdata_full v)
{
	fixed3 direction = lerp(v.normal, _Gravity * _GravityStrength + v.normal * (1-_GravityStrength), FUR_MULTIPLIER);
	v.vertex.xyz += direction * _FurLength * FUR_MULTIPLIER * v.color.a;
}

它的表面着色器负责判断哪些像素应该被显示或隐藏（同时考虑了观察角度）

void surf (Input IN, inout SurfaceOutputStandard o) {
	fixed4 c = tex2D (_MainTex, IN.uv_MainTex) * _Color;
	o.Albedo = c.rgb;
	o.Metallic = _Metallic;
	o.Smoothness = _Glossiness;

	o.Alpha = step(lerp(_Cutoff,_CutoffEnd,FUR_MULTIPLIER), c.a);

	float alpha = 1 - (FUR_MULTIPLIER * FUR_MULTIPLIER);
	alpha += dot(IN.viewDir, o.Normal) - _EdgeFade;

	o.Alpha *= alpha;
}

在普通表面着色器CGEND之后，添加多个该pass，越多则越真实
这种方法非常耗时

向着色器传数组（实现HeatMap）

C#部分：material.SetVectorArray("_Properties", properties);
shader部分：uniform float2 _Properties[20];

heatMap实现方法：通过传入的position数组中点的位置和半径累计热度值h，再根据h绘制上颜色

			half4 frag(vertOutput output) : COLOR
			{
				half h = 0;

				for (int i = 0; i < _Points_Length; i++)
				{
					half di = distance(output.worldPos, _Points[i].xyz);

					half ri = _Properties[i].x;
					half hi = 1- saturate(di / ri);

					h += hi * _Properties[i].y;
				}

				h = saturate(h);
				half4 color = tex2D(_HeatTex, fixed2(h, 0));
				return color;
			}