前言
上一节，达成了水面与水底的深度判断，结果用RawDepth表示。这一节梳理利用深度关系生成岸边的泡沫。
设计函数_getFoam(RawDepth)
float sinWave = _getFoam(RawDepth) ;
_getFoam函数
这个函数的作用是生成岸边的泡沫，使用sin函数利用RawDepth生成岸边的条纹，同时RawDepth改承担mask的任务，迫使条纹只在岸边生成
变量设计
[Space][Header(_______BlendCtrl_______)][Space]_FoamBlend("Water-Shore mixture", Range(0,1)) = 0 //水面和岸边的衔接柔和程度，在这里用作mask过度控制[Space][Header(_______FoamCtrl_______)][Space]_FoamRange("Foam Range", Range(0,1)) = 0_FoamFreq("Foam Freq", Float) = 10_FoamSpeed("Foam Speed", Float) = 1
sin函数生成wave
_FoamRange整体微调波长_FoamFreq频率调整，泡沫生成间隔_FoamSpeed速度float _getFoam(float depth){depth = clamp(depth/_FoamRange,0,1);float a = depth * _FoamFreq + _Time.y * _FoamSpeed;float sinWave = sin(a)return sinWave;}
fig1 clamp(depth/_FoamRange,0,1)
fig2 多余的波峰
删除多余的波峰
float FoamDepth = smoothstep(_FoamBlend, 1, depth);
fig3 根据depth做简单的计算，生成对比度更高的mask
mask加入计算后_getFoam函数如下所示
float _getFoam(float depth){depth = clamp(depth/_FoamRange,0,1);float a = depth * _FoamFreq + _Time.y * _FoamSpeed;float FoamDepth = smoothstep(_FoamBlend, 1, depth);float sinWave = sin(a) * (1-FoamDepth);return sinWave;}
异形条纹
添加采样噪声的选项
float _getFoamWave(float depth, float wave_noise){depth = clamp(depth/_FoamRange,0,1);float a = depth * _FoamFreq + _Time.y * _FoamSpeed;float FoamDepth = smoothstep(_FoamBlend, 1, depth);float sinWave = sin(a) + wave_noise;sinWave = sinWave * (1-FoamDepth);return sinWave;}
函数_getFoamWave的新的变量wave_noise就是我们采样的noise数据
泡沫消融和增强
处理方式不唯一
现在得到了边缘不平以及明暗各异的条纹现在所做的是加入_FoamDissolve这一控制变量
depth- _FoamDissolve这一算式代表：离岸越近，消融程度越高
float _getFoamWave(float depth, float wave_noise){depth = clamp(depth/_FoamRange,0,1);float a = depth * _FoamFreq + _Time.y * _FoamSpeed;float FoamDepth = smoothstep(_FoamBlend, 1, depth);float FoamDepth_oneminus = 1-FoamDepth;float sinWave = sin(a) + wave_noise + (depth- _FoamDissolve);sinWave = sinWave * FoamDepth_oneminus;return sinWave;}
极端地将_FoamDissolve归0，条纹之间过度生硬
为了解决这一问题将二分处填充0-1的插值
float _getFoamWave(float depth, float wave_noise){depth = clamp(depth/_FoamRange,0,1);float a = depth * _FoamFreq + _Time.y * _FoamSpeed;float FoamDepth = smoothstep(_FoamBlend, 1, depth);float FoamDepth_oneminus = 1-FoamDepth;float sinWave = sin(a) + wave_noise + depth - _FoamDissolve;sinWave = smoothstep(FoamDepth_oneminus-_FoamFade,1,sinWave);sinWave = sinWave * FoamDepth_oneminus;return sinWave;}
最后的结果如上图所示
