EN中文
开发者社区 > 程序

Shader实例（流光实现）

发表于2018-04-12
评论0 3.2k浏览
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  
        ｝  
    ｝  
｝
来自：https://blog.csdn.net/cjb_king/article/details/78869642

如社区发表内容存在侵权行为，您可以点击这里查看侵权投诉指引

标签：

JavaScript光照Unity渲染进阶