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Shader实例(流光实现)

文章来自CSDN博客 2018-04-12 335浏览

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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