Shader实例（流光实现）
- 2019 年 12 月 2 日
- 筆記
版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
本文链接：https://blog.csdn.net/CJB_King/article/details/78869642
Shader实例（流光实现）
流光效果
首先来看一下流光效果。流光效果是一个非常常见的效果，不仅仅是游戏，一些广告之类的也都会有这种效果。流光的原理还是比较简单的：首先就是需要一张流光图，这张流光图的大部分都是黑色，然后有一条亮线，然后我们在采样的时候，最终输出叠加上这张图的采样值，并根据时间调整采样的UV就可以有流光的效果啦。下面是一个比较简单的流光效果实现：
下面看属性参数：
接下来是SubShader中的一些参数定义
顶点函数处理
光照处理
以上是对于2D图像常用的流光实现方式，如果是3D物体用这种方式的话，可能会出现问题，所以对于3D物体，采用按照物体的世界坐标按时间偏移查询纹理贴图就行了
具体参数按需求改下就好了
按照方向消失或重现效果
我们再来看一个用模型空间坐标作为采样的uv的栗子，也是一种比较好玩的效果。比如我们需要一个模型身体按照一定的方向逐渐消失，直至全部消失掉的一个效果。下面说一下思路，与世界空间采样的流光效果一样，我们在vertex阶段记录一下vertex坐标，传递给fragment阶段，在fragment阶段用这个值和一个设定好的阈值进行比较，不满足条件的像素点直接discard，逐渐调整阈值，就可以得到让模型按照某个方向消失的效果了。代码如下：
//按照方向消失的效果 //by:CJB_King //2017.12.23 Shader "SelfShader/DissolveEffectX" { Properties { _MainTex("MainTex(RGB)", 2D) = "white" {} _DissolveVector("DissolveVector", Vector) = (0,0,0,0) } CGINCLUDE #include "Lighting.cginc" uniform sampler2D _MainTex; uniform float4 _MainTex_ST; uniform float4 _DissolveVector; struct v2f { float4 pos : SV_POSITION; float3 worldNormal : NORMAL; float2 uv : TEXCOORD0; float3 worldLight : TEXCOORD1; float4 objPos : TEXCOORD2; }; v2f vert(appdata_base v) { v2f o; o.pos = mul(UNITY_MATRIX_MVP, v.vertex); o.uv = TRANSFORM_TEX(v.texcoord, _MainTex); //顶点转化到世界空间 o.objPos = v.vertex; o.worldNormal = UnityObjectToWorldNormal(v.normal); o.worldLight = UnityObjectToWorldDir(_WorldSpaceLightPos0.xyz); return o; } fixed4 frag(v2f i) : SV_Target { half3 normal = normalize(i.worldNormal); half3 light = normalize(i.worldLight); fixed diff = max(0, dot(normal, light)); fixed4 albedo = tex2D(_MainTex, i.uv); //不满足条件的discard clip(i.objPos.xyz - _DissolveVector.xyz); fixed4 c; c.rgb = diff * albedo; c.a = 1; return c; } ENDCG SubShader { Pass { Tags{ "RenderType" = "Opaque" } CGPROGRAM #pragma vertex vert #pragma fragment frag ENDCG } } FallBack "Diffuse" }
还有一个小问题，其实上图中的例子里面，模型从上到下，理想情况应该是调整Y轴，不过例子里面调整的确实X轴，原因应该与Unity导入之后会绕着X轴旋转90度有关，也就是原本在max里面的Y轴变成Unity里面的X轴。
下面，我们再看一下增加了边缘高亮的消失效果，为了让模消失的型边缘高亮，我们通过将用于clip的factor值与另一个高亮阈值值进行比较，如果factor小于高亮阈值，则返回一个高亮的颜色值，否则正常渲染。这样模型就总共有三种显示状态：clip状态，高亮状态，正常状态。代码如下：
//消失效果 //by：CJB_King //2017.12.23 Shader "SelfShader/DissolveEffectX" { Properties{ _Diffuse("Diffuse", Color) = (1,1,1,1) _DissolveColor("Dissolve Color", Color) = (0,0,0,0) _MainTex("Base 2D", 2D) = "white"{} _ColorFactor("ColorFactor", Range(0,1)) = 0.7 _DissolveThreshold("DissolveThreshold", Float) = 0 } CGINCLUDE #include "Lighting.cginc" uniform fixed4 _Diffuse; uniform fixed4 _DissolveColor; uniform sampler2D _MainTex; uniform float4 _MainTex_ST; uniform float _ColorFactor; uniform float _DissolveThreshold; struct v2f { float4 pos : SV_POSITION; float3 worldNormal : TEXCOORD0; float2 uv : TEXCOORD1; float4 objPos : TEXCOORD2; }; v2f vert(appdata_base v) { v2f o; o.pos = mul(UNITY_MATRIX_MVP, v.vertex); o.uv = TRANSFORM_TEX(v.texcoord, _MainTex); o.worldNormal = mul(v.normal, (float3x3)unity_WorldToObject); o.objPos = v.vertex; return o; } fixed4 frag(v2f i) : SV_Target { float factor = i.objPos.x - _DissolveThreshold; clip(factor); //Diffuse + Ambient光照计算 fixed3 worldNormal = normalize(i.worldNormal); fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz); fixed3 lambert = saturate(dot(worldNormal, worldLightDir)); fixed3 albedo = lambert * _Diffuse.xyz * _LightColor0.xyz + UNITY_LIGHTMODEL_AMBIENT.xyz; fixed3 color = tex2D(_MainTex, i.uv).rgb * albedo; //等价于下面注释代码的操作 fixed lerpFactor = saturate(sign(_ColorFactor - factor)); return lerpFactor * _DissolveColor + (1 - lerpFactor) * fixed4(color, 1); /* if (factor < _ColorFactor) { return _DissolveColor; } return fixed4(color, 1);*/ } ENDCG SubShader { Tags{ "RenderType" = "Opaque" } Pass { //不让模型穿帮，关掉了背面裁剪 Cull Off CGPROGRAM #pragma vertex vert #pragma fragment frag ENDCG } } FallBack "Diffuse" }
溶解效果进阶版
之前的文章里，我们研究过溶解效果，不过这个效果是基于全身的，我们来尝试一下，把上面按照方向消失的效果与溶解效果结合起来，做成一个按照某个方向逐渐溶解的效果。要得到随机的溶解效果，我们需要采样一张噪声图，然后在原本会直接clip掉的部分根据采样的噪声图进行clip，就能得到按照方向的溶解效果啦。
//溶解效果 //by：CJB_King //2017.12.23 Shader "SelfShader/DissolveEffectX" { Properties{ _Diffuse("Diffuse", Color) = (1,1,1,1) _DissolveColor("Dissolve Color", Color) = (1,1,1,1) _MainTex("Base 2D", 2D) = "white"{} _DissolveMap("DissolveMap", 2D) = "white"{} _DissolveThreshold("DissolveThreshold", Range(0,1)) = 0 _DissolveSpeedFactor("DissolveSpeed", Range(0,5)) = 2 _DissolveControl("ColorFactorB", Float) = 0 } CGINCLUDE #include "Lighting.cginc" uniform fixed4 _Diffuse; uniform fixed4 _DissolveColor; uniform sampler2D _MainTex; uniform float4 _MainTex_ST; uniform sampler2D _DissolveMap; uniform float _DissolveThreshold; uniform float _DissolveSpeedFactor; uniform float _DissolveControl; struct v2f { float4 pos : SV_POSITION; float3 worldNormal : TEXCOORD0; float2 uv : TEXCOORD1; float4 objPos : TEXCOORD2; }; v2f vert(appdata_base v) { v2f o; o.pos = mul(UNITY_MATRIX_MVP, v.vertex); o.uv = TRANSFORM_TEX(v.texcoord, _MainTex); o.worldNormal = mul(v.normal, (float3x3)unity_WorldToObject); o.objPos = v.vertex; return o; } fixed4 frag(v2f i) : SV_Target { fixed4 dissolve = tex2D(_DissolveMap, i.uv); //Diffuse + Ambient光照计算 fixed3 worldNormal = normalize(i.worldNormal); fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz); fixed3 lambert = saturate(dot(worldNormal, worldLightDir)); fixed3 albedo = lambert * _Diffuse.xyz * _LightColor0.xyz + UNITY_LIGHTMODEL_AMBIENT.xyz; fixed3 color = tex2D(_MainTex, i.uv).rgb * albedo; float factor = i.objPos.x - _DissolveControl; if(factor < 0) { clip(_DissolveThreshold - dissolve.r * abs(factor) * _DissolveSpeedFactor); } return fixed4(color, 1); } ENDCG SubShader { Tags{ "RenderType" = "Opaque" } Pass { Cull Off CGPROGRAM #pragma vertex vert #pragma fragment frag ENDCG } } FallBack "Diffuse" }
Shader "SelfShader/Dissolve" { Properties { _MainColor("MainColor",COLOR)=(1,1,1,1) _MainTex ("Texture", 2D) = "white" {} _Noise("Noise",2D)="white"{} _Dissolve("Dissolve",Vector)=(0.2,0.5,0.8) _DissolveThread("DissolveThread",float)=0.2 _DissolveColor("DissolveColor",COLOR)=(1,1,1,1) _DissolveColFactor("_DissolveColFactor",float)=2 _FlyFactor("FlyFactor",float)=3 } SubShader { Tags { "RenderType"="Opaque" } LOD 100 Pass { CGPROGRAM #pragma vertex vert #pragma fragment frag #include "UnityCG.cginc" #include "Lighting.cginc" struct a2v { float4 vertex : POSITION; float2 uv : TEXCOORD0; fixed3 normal:NORMAL; }; struct v2f { float2 uv : TEXCOORD0; float4 pos : SV_POSITION; fixed3 worldNormal:TEXCOORD1; fixed3 worldPos:TEXCOORD2; fixed3 objPos:TEXCOORD3; }; sampler2D _Noise; sampler2D _MainTex; float4 _MainTex_ST; fixed4 _MainColor; fixed4 _Dissolve; float _DissolveThread; fixed4 _DissolveColor; float _DissolveColFactor; float _FlyFactor; v2f vert (a2v v) { v2f o; o.pos = UnityObjectToClipPos(v.vertex); o.worldPos=mul((float3x3)unity_ObjectToWorld,v.vertex); o.worldNormal=UnityObjectToWorldNormal(v.normal); o.objPos=v.vertex; o.uv = TRANSFORM_TEX(v.uv, _MainTex); o.pos.xyz+=v.normal*saturate(_DissolveThread-_FlyFactor)*_FlyFactor; return o; } fixed4 frag (v2f i) : SV_Target { fixed3 worldNor=normalize(i.worldNormal); fixed3 lightDir=normalize(_WorldSpaceLightPos0.xyz); fixed4 albedo = tex2D(_MainTex, i.uv)*_MainColor; fixed4 noiseColor=tex2D(_Noise,i.uv); float factor=noiseColor.r-_DissolveThread; clip(factor); fixed3 ambient=UNITY_LIGHTMODEL_AMBIENT.xyz*albedo.rgb; fixed3 diffuse=_LightColor0.rgb*albedo.rgb*(0.5*dot(lightDir,worldNor)+0.5); float lerpFactor=saturate(sign(_DissolveColFactor-factor)); return lerp(fixed4(ambient+diffuse,1),_DissolveColor,lerpFactor); } ENDCG } } }
