1.实现原理
1.颜色公式
col = a + b* cos(2PI * (ct + d))
更多的颜色变换:
比如彩虹的颜色公式：
col = .6 + .6 * cos( 6.3 * uv.y / _ScreenParam.y *2. + float4(0,23,21,0) );
2.绘制高光
一个小圆减去一个大圆就是一个月牙弧，如果要调整弧度，可以改变两个圆之间的大小比例，位置偏移。如果圆无法满足要求，则使用椭圆来进行集合操作
3.绘制波浪
使用RayMarch方式在原点绘制一个圆盘，然后通过在y值使用两个sin来合成一个小的wave，将这个渲染的结果通过类似贴图的方式贴在水面之上，通过时间控制其y值偏移即可。
raymarch 和 海洋的渲染 我其他的文章有涉及，这里就不说了
4.绘制泡泡
. 绘制一个反向圆，然后在里面绘制几个小圆模拟高光
. 泡泡的运动分为两部分：
- y轴匀速
- x轴先的加速度，后sin移动：在圆的底面随机沿着90-range(-60,60)的角度发射一定的初速度，然后添加一个负的加速度，当在x的方向的速度为0的时候停止加速度然后sin函数来控制泡泡左右移动，增加点动态。自己在稿纸上计算其积分，套进去就可以了。
5.这是一个特效。
灵感也是来自一个特效。所以代码中会有很多hack的数字，目的都是为了美术表现，所以怎么好看怎么来
5.源码
// create by JiepengTan
// https://github.com/JiepengTan/FishManShaderTutorial2018-03-25 email: jiepengtan@gmail.com
Shader "FishManShaderTutorial/GameHPUI" {
Properties{
_MainTex("Base (RGB)", 2D) = "white" {}
_LoopNum ("_LoopNum", Vector) = (314.,1., 1, 1)
}
SubShader
{
Tags { "RenderType"="Opaque" }
LOD 100
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
#include "ShaderLibs/Math.cginc"
#define SIZE 0.5
#define WATER_DEEP 0.6
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
};
float Rand(float x)
{
return frac(sin(x*866353.13)*613.73);
}
float2x2 Rotate2D(float deg){
deg = deg * Deg2Radius;
return float2x2(cos(deg),sin(deg),-sin(deg),cos(deg));
}
float2 Within(float2 uv, float4 rect) {
return (uv-rect.xy)/(rect.zw-rect.xy);
}
float Remap(float a,float b,float c,float d,float val){
return (val-a)/(b-a) * (d-c) + c;
}
float Circle(float2 uv,float2 center,float size,float blur){
uv = uv - center;
uv /= size;
float len = length(uv);
return smoothstep(1.,1.-blur,len);
}
float PureCircle(float2 uv,float2 center,float size,float blur,float powVal){
uv = uv - center;
uv /= size;
float len = 1.-length(uv);
float val = clamp(Remap(0.,blur,0.,1.,len),0.,1.);
return pow(val,powVal);//* pow(1.+len * 3.,0.1);
}
float Ellipse(float2 uv,float2 center,float2 size,float blur){
uv = uv - center;
uv /= size;
float len = length(uv);
return smoothstep(1.,1.-blur,len);
}
float3 Draw3DFrame(float2 uv){
//cameraPos
float3 camPos = float3(0.,0.,-3);
//Torus
float3 frameCol = float3(0.9,0.75,0.6);
float frameMask = Circle(uv,float2(0.,0.),SIZE*1.1,0.01) -
Circle(uv,float2(0.,0.),SIZE,0.01);
return float3(0.,0.,0.);
}
float Torus2D(float2 uv,float2 center,float2 size,float blur){
uv = uv - center;
float len = length(uv);
if(len<size.y || len >size.x)
return 0.;
float radio = (len-size.y)/(size.x-size.y);
float val = 1.-abs((radio-0.5)*2.);
return pow(val,blur);
}
float3 DrawFrame(float2 uv){
float3 frameCol = float3(0.9,0.75,0.6);
float frameMask = Circle(uv,float2(0.,0.),SIZE*1.1,0.01) -
Circle(uv,float2(0.,0.),SIZE,0.01);
//return frameCol * frameMask;
return Torus2D(uv,float2(0.,0.),float2(SIZE * 1.1,SIZE),0.2) *frameCol;
}
float3 DrawHightLight(float2 uv){
//up
float3 hlCol = float3(0.95,0.95,0.95);
float upMask = Ellipse(uv,float2(0.,0.8)*SIZE,float2(0.9,0.7)*SIZE,0.6)*0.9;
upMask = upMask * Circle(uv,float2(0.,0.)*SIZE,SIZE*0.95,0.02) ;
upMask = upMask * Circle(uv,float2(0.,-0.9)*SIZE,SIZE*1.1,-0.8) ;
//bottom
uv =mul(Rotate2D(30.),uv) ;
float btMask =1.;
btMask *= Circle(uv,float2(0.,0.)*SIZE,SIZE*0.95,0.02);
float scale = 0.9;
btMask *= 1.- Circle(uv,float2(0.,-0.17+scale)*SIZE,SIZE*(1.+scale),0.2) ;
return (upMask + btMask) * hlCol;
}
float GetWaveHeight(float2 uv){
uv =mul(Rotate2D(-30.),uv) ;
float wave = 0.12*sin(-2.*uv.x+_Time.y*4.);
uv =mul(Rotate2D(-50.),uv) ;
wave += 0.05*sin(-2.*uv.x+_Time.y*4.);
return wave;
}
float RayMarchWater(float3 camera, float3 dir,float startT,float maxT){
float3 pos = camera + dir * startT;
float t = startT;
for(int i=0;i<150;i++){
if(t > maxT){
return -1.;
}
float h = GetWaveHeight(pos.xz) * WATER_DEEP;
if(h + 0.01 > pos.y ) {//+ 0.01 acc intersect speed
// get the intersect point
return t;
}
t += pos.y - h;
pos = camera + dir * t;
}
return -1.0;
}
float4 SimpleWave3D(float2 uv,float3 col){
float3 camPos =float3(0.23,0.13,-2.28);
float3 targetPos = float3(0.,0.,0.);
float3 f = normalize(targetPos-camPos);
float3 r = cross(normalize(float3(0.01, 1., 0.)), f);
float3 u = cross(f, r);
float3 ray = normalize(uv.x*r+uv.y*u+1.0*f);
float startT = 0.1;
float maxT = 20.;
float dist = RayMarchWater(camPos, ray,startT,maxT);
float3 pos = camPos + ray * dist;
//only need a small circle
float circleSize = 2.;
if(dist < 0.){
return float4(0.,0.,0.,0.);
}
float2 offsetPos = pos.xz;
if(length(offsetPos)>circleSize){
return float4(0.,0.,0.,0.);
}
float colVal = 1.-((pos.z+0.)/circleSize +1.0) *.5;//0~1
return float4(col*smoothstep(0.,1.4,colVal),1.);
}
float SmoothCircle(float2 uv,float2 offset,float size){
uv -= offset;
uv/=size;
float temp = clamp(1.-length(uv),0.,1.);
return smoothstep(0.,1.,temp);
}
float DrawBubble(float2 uv,float2 offset,float size){
uv = (uv - offset)/size;
float val = 0.;
val = length(uv);
val = smoothstep(0.5,2.,val)*step(val,1.);
val +=SmoothCircle(uv,float2(-0.2,0.3),0.6)*0.4;
val +=SmoothCircle(uv,float2(0.4,-0.5),0.2)*0.2;
return val;
}
float DrawBubbles(float2 uv){
uv = Within(uv, float4(-SIZE,-SIZE,SIZE,SIZE));
uv.x-=0.5;
float val = 0.;
const float count = 2.;// bubble num per second
const float maxVY = 0.1;
const float ay = -.3;
const float ax = -.5;
const float maxDeg = 80.;
const float loopT = maxVY/ay + (1.- 0.5*maxVY*maxVY/ay)/maxVY;
const float num = loopT*count;
for(float i=1.;i<num;i++){
float size = 0.02*Rand(i*451.31)+0.02;
float t = fmod(_Time.y + Rand(i)*loopT,loopT);
float deg = (Rand(i*1354.54)*maxDeg +(90.-maxDeg*0.5))*Deg2Radius;
float2 vel = float2(cos(deg),sin(deg));
float ty = max((vel.y*0.3 - maxVY),0.)/ay;
float yt = clamp(t,0.,ty);
float y = max(0.,abs(vel.y)*yt + 0.5*ay*yt*yt) + max(0.,t-ty)*maxVY;// 加点加速度
float tx = abs(vel.x/ax);
t = min(tx,t);
float xOffset = abs(vel.x)*t+0.5*ax*t*t + sin(_Time.y*(0.5+Rand(i)*2.)+Rand(i)*2.*PI)*0.03;
float x = sign(vel.x)*xOffset;
float2 offset = float2(x,y);
val += DrawBubble(uv,offset,size*0.5);
}
return val;
}
v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = v.uv;
return o;
}
float4 frag (v2f i) : SV_Target
{
float hpPer = sin(_Time.y*0.2)*0.4+0.5;
float3 waterCol = 0.5+0.5*cos(2.*PI*(float3(1.,1.,1.)*_Time.y*0.2+float3(0.,0.33,0.67)));
float2 uv = (i.uv/1 - 0.5)*1/1*2.;
float3 col = float3(0.,0.,0.);//final color
//draw 3D frame
col += DrawFrame(uv);
//draw base water
float hpPerMask = step(0.,(hpPer *2. -1.)*SIZE - uv.y);
float bgMask = 0.;
bgMask += PureCircle(uv,float2(0.,0.),SIZE*1.1,.9,0.9);
bgMask += Circle(uv,float2(0.,0.),SIZE,.6)*0.2;
col += bgMask * waterCol *hpPerMask ;
//draw wave
float waterMask = step(length(uv),SIZE);
float offset = hpPer -0.5+0.01;
float wavePicSize = 0.8*SIZE;
float2 remapUV = Within(uv,float4(0.,offset,wavePicSize,offset+wavePicSize-0.2));
float4 wave = SimpleWave3D(remapUV,waterCol);
col = lerp(col,wave.xyz*bgMask,wave.w*waterMask);
//draw bubbles
float bubbleMask = smoothstep(0.,0.1,(hpPer *2. -1.2)*SIZE - uv.y);
col+= DrawBubbles(uv)*float3(1.,1.,1.)* bubbleMask*waterMask;
//draw hight light
col += DrawHightLight(uv*1.);
return float4(col,1.);
}
ENDCG
}
}
FallBack Off
}