shaderbrew/gen-smite.html at master · web3dev1337/shaderbrew · GitHub

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<!DOCTYPE html>
<html><head><meta charset="utf-8"><title>Lightning Smite — Tall Sprite Generator</title></head>
<body>
<div id="status">Loading...</div>
<script type="importmap">
{"imports":{"three":"https://unpkg.com/three@0.174.0/build/three.module.min.js"}}
</script>
<script type="module">
import * as THREE from "three";

// Tall frame: 128 wide × 512 tall (1:4 ratio)
const W=128,H=512,FRAMES=36;
const status=document.getElementById("status");
status.textContent=`Rendering ${FRAMES} frames at ${W}x${H}...`;

const cv=document.createElement("canvas");cv.width=W;cv.height=H;
const r3=new THREE.WebGLRenderer({canvas:cv,alpha:true,preserveDrawingBuffer:true});
r3.setSize(W,H,false);r3.autoClear=true;
function makeRT(){return new THREE.WebGLRenderTarget(W,H,{minFilter:THREE.LinearFilter,magFilter:THREE.LinearFilter,type:THREE.UnsignedByteType});}

const ppV=`varying vec2 vUv;void main(){vUv=uv;gl_Position=vec4(position.xy,0.0,1.0);}`;

const NOISE_LIB=`
vec3 mod289(vec3 x){return x-floor(x*(1./289.))*289.;}
vec4 mod289(vec4 x){return x-floor(x*(1./289.))*289.;}
vec4 permute(vec4 x){return mod289(((x*34.)+1.)*x);}
vec4 taylorInvSqrt(vec4 r){return 1.79284291400159-.85373472095314*r;}
float snoise(vec3 v){
  const vec2 C=vec2(1./6.,1./3.);const vec4 D=vec4(0.,.5,1.,2.);
  vec3 i=floor(v+dot(v,C.yyy));vec3 x0=v-i+dot(i,C.xxx);
  vec3 g=step(x0.yzx,x0.xyz);vec3 l=1.-g;
  vec3 i1=min(g.xyz,l.zxy);vec3 i2=max(g.xyz,l.zxy);
  vec3 x1=x0-i1+C.xxx;vec3 x2=x0-i2+C.yyy;vec3 x3=x0-D.yyy;
  i=mod289(i);
  vec4 p=permute(permute(permute(i.z+vec4(0.,i1.z,i2.z,1.))+i.y+vec4(0.,i1.y,i2.y,1.))+i.x+vec4(0.,i1.x,i2.x,1.));
  float n_=.142857142857;vec3 ns=n_*D.wyz-D.xzx;
  vec4 j=p-49.*floor(p*ns.z*ns.z);
  vec4 x_=floor(j*ns.z);vec4 y_=floor(j-7.*x_);
  vec4 x=x_*ns.x+ns.yyyy;vec4 y=y_*ns.x+ns.yyyy;
  vec4 h=1.-abs(x)-abs(y);vec4 b0=vec4(x.xy,y.xy);vec4 b1=vec4(x.zw,y.zw);
  vec4 s0=floor(b0)*2.+1.;vec4 s1=floor(b1)*2.+1.;
  vec4 sh=-step(h,vec4(0.));
  vec4 a0=b0.xzyw+s0.xzyw*sh.xxyy;vec4 a1=b1.xzyw+s1.xzyw*sh.zzww;
  vec3 p0=vec3(a0.xy,h.x);vec3 p1=vec3(a0.zw,h.y);vec3 p2=vec3(a1.xy,h.z);vec3 p3=vec3(a1.zw,h.w);
  vec4 norm=taylorInvSqrt(vec4(dot(p0,p0),dot(p1,p1),dot(p2,p2),dot(p3,p3)));
  p0*=norm.x;p1*=norm.y;p2*=norm.z;p3*=norm.w;
  vec4 m=max(.6-vec4(dot(x0,x0),dot(x1,x1),dot(x2,x2),dot(x3,x3)),0.);
  m=m*m;return 42.*dot(m*m,vec4(dot(p0,x0),dot(p1,x1),dot(p2,x2),dot(p3,x3)));
}
float hash(float n){return fract(sin(n)*43758.5453);}
float hash21(vec2 p){return fract(sin(dot(p,vec2(127.1,311.7)))*43758.5453);}
`;

const smiteShader=`
uniform float time;
uniform vec2 resolution;
${NOISE_LIB}

float smiteBolt(vec2 p,vec2 a,vec2 b,float noiseT,float sd,float thickness){
  vec2 ab=b-a;
  float len=length(ab);
  vec2 dir=ab/len;
  vec2 perp=vec2(-dir.y,dir.x);
  float along=dot(p-a,dir)/len;
  float across=dot(p-a,perp);
  if(along<-0.05||along>1.05)return 0.0;

  float disp=0.0;
  disp+=snoise(vec3(along*6.0+sd,noiseT*6.0,sd*5.0))*0.06*len;
  disp+=snoise(vec3(along*14.0+sd*3.0,noiseT*10.0,sd*9.0))*0.025*len;
  disp+=snoise(vec3(along*30.0+sd*7.0,noiseT*15.0,sd*13.0))*0.01*len;

  float d=abs(across-disp);
  float core=exp(-d*d/(thickness*thickness));
  float glow=exp(-d*d/(thickness*6.0*thickness*6.0))*0.4;
  float edge=smoothstep(0.0,0.06,along)*smoothstep(1.0,0.94,along);
  return (core+glow)*edge;
}

void main(){
  vec2 uv=gl_FragCoord.xy/resolution;
  // Tall aspect: x in [-0.25,0.25], y in [-1,1]
  float aspect=resolution.x/resolution.y;
  vec2 p=vec2((uv.x-0.5)*2.0*aspect,(uv.y-0.5)*2.0);

  float phase=clamp(time,0.0,1.0);

  float leaderProgress=smoothstep(0.0,0.3,phase);
  float strikeFlash=smoothstep(0.25,0.3,phase)*smoothstep(0.5,0.35,phase);
  float sustained=smoothstep(0.3,0.4,phase)*smoothstep(1.0,0.7,phase);
  float fade=smoothstep(0.7,1.0,phase);

  vec2 skyTop=vec2(0.0,0.95);
  vec2 impact=vec2(0.0,-0.9);
  vec2 currentEnd=mix(skyTop,impact,leaderProgress);

  float lightning=0.0;
  float noiseT=time*3.0;
  float boltSeed=floor(time*0.5)*7.13;

  float brightness=0.3*smoothstep(0.0,0.05,phase);
  brightness+=2.5*strikeFlash;
  brightness+=sustained*(0.7+0.3*sin(noiseT*20.0+snoise(vec3(noiseT*5.0,0.0,0.0))*5.0));
  brightness*=(1.0-fade);

  // Main bolt
  float mainBolt=smiteBolt(p,skyTop,currentEnd,noiseT,boltSeed,0.006);
  lightning+=mainBolt*brightness;

  // Secondary bolt
  float secondBolt=smiteBolt(p,skyTop+vec2(0.008,0.0),currentEnd+vec2(-0.005,0.0),noiseT+10.0,boltSeed+3.0,0.004);
  lightning+=secondBolt*brightness*0.5;

  // Branches
  if(leaderProgress>0.3){
    for(int i=0;i<8;i++){
      float fi=float(i);
      float branchT=0.1+fi*0.1;
      if(branchT>leaderProgress)continue;
      vec2 branchStart=mix(skyTop,currentEnd,branchT);
      float mainDisp=snoise(vec3(branchT*6.0+boltSeed,noiseT*6.0,boltSeed*5.0))*0.06*length(currentEnd-skyTop);
      branchStart.x+=mainDisp;

      float branchAngle=hash(boltSeed+fi*7.0)*1.2-0.6+1.5708;
      float branchLen=0.05+hash(boltSeed+fi*13.0)*0.08;
      vec2 branchDir=vec2(cos(branchAngle),sin(branchAngle));
      if(mod(fi,2.0)<1.0) branchDir.x*=-1.0;
      branchDir.y=-abs(branchDir.y)*0.4;
      vec2 branchEnd=branchStart+normalize(branchDir)*branchLen;

      float branch=smiteBolt(p,branchStart,branchEnd,noiseT,boltSeed+fi*11.0,0.003);
      lightning+=branch*brightness*0.5;

      // Sub-branch
      vec2 subStart=mix(branchStart,branchEnd,0.5);
      vec2 subEnd=subStart+normalize(branchDir)*branchLen*0.4;
      lightning+=smiteBolt(p,subStart,subEnd,noiseT,boltSeed+fi*23.0,0.002)*brightness*0.25;
    }
  }

  // Impact effects
  float impactGlow=exp(-length(p-impact)*12.0)*strikeFlash*3.0;
  float groundGlow=exp(-length(p-impact)*6.0)*sustained*(1.0-fade)*0.8;

  // Ground sparks
  float sparks=0.0;
  if(phase>0.3){
    for(int i=0;i<10;i++){
      float fi=float(i);
      float sparkPhase=(phase-0.3)*2.5;
      float sparkAngle=-1.5708+hash(boltSeed+fi*31.0)*3.14159-1.5708;
      float sparkSpeed=0.2+hash(boltSeed+fi*37.0)*0.3;
      vec2 sparkPos=impact;
      sparkPos.x+=sin(sparkAngle)*sparkSpeed*sparkPhase;
      sparkPos.y+=cos(sparkAngle)*sparkSpeed*sparkPhase-1.5*sparkPhase*sparkPhase;
      float sparkLife=1.0-smoothstep(0.2,0.6,sparkPhase);
      sparks+=exp(-length(p-sparkPos)*60.0)*sparkLife*0.4;
    }
  }

  // Sky illumination
  float skyGlow=exp(-(p.y-0.7)*(p.y-0.7)*1.5)*exp(-p.x*p.x*20.0)*brightness*0.2;

  // Vertical atmospheric column glow
  float colGlow=exp(-p.x*p.x*80.0)*sustained*(1.0-fade)*0.15;

  // Color
  vec3 col=vec3(0);
  vec3 boltCore=vec3(0.9,0.93,1.0);
  vec3 boltGlow=vec3(0.4,0.5,1.0);
  vec3 impactAmber=vec3(1.0,0.8,0.4);
  vec3 sparkColor=vec3(1.0,0.9,0.5);
  vec3 skyViolet=vec3(0.3,0.2,0.6);
  vec3 colBlue=vec3(0.2,0.3,0.8);

  col+=mix(boltGlow,boltCore,clamp(lightning*0.5,0.0,1.0))*lightning;
  col+=impactAmber*(impactGlow+groundGlow);
  col+=sparkColor*sparks;
  col+=skyViolet*skyGlow;
  col+=colBlue*colGlow;

  // Alpha: transparent background, bolt is opaque
  float alpha=clamp(lightning+impactGlow+groundGlow+sparks+skyGlow*2.0+colGlow*2.0,0.0,1.0);

  gl_FragColor=vec4(col,alpha);
}`;

// ==================== RENDERING ====================
const pixBuf=new Uint8Array(W*H*4);
const fxScene=new THREE.Scene(),fxCam=new THREE.Camera();
const fxPlane=new THREE.Mesh(new THREE.PlaneGeometry(2,2));
fxScene.add(fxPlane);

function renderFrame(t,target){
  const mat=new THREE.ShaderMaterial({
    uniforms:{time:{value:t},resolution:{value:new THREE.Vector2(W,H)}},
    vertexShader:ppV,fragmentShader:smiteShader,
    depthTest:false,depthWrite:false,transparent:true
  });
  fxPlane.material=mat;
  r3.setRenderTarget(target);r3.clear();
  r3.render(fxScene,fxCam);
  r3.setRenderTarget(null);
  mat.dispose();
}

const fxRT=makeRT();
const frameCanvas=document.createElement("canvas");
frameCanvas.width=W;frameCanvas.height=H;
const fctx=frameCanvas.getContext("2d",{willReadFrequently:true});

window.__frames=[];
window.__done=false;

const tStart=0,tEnd=1.0;
for(let f=0;f<FRAMES;f++){
  const t=tStart+(f/(FRAMES-1))*(tEnd-tStart);
  status.textContent=`Frame ${f+1}/${FRAMES}...`;
  renderFrame(t,fxRT);
  r3.readRenderTargetPixels(fxRT,0,0,W,H,pixBuf);
  const img=fctx.createImageData(W,H);
  for(let y=0;y<H;y++){
    const s=(H-1-y)*W*4,d=y*W*4;
    for(let x=0;x<W*4;x++)img.data[d+x]=pixBuf[s+x];
  }
  fctx.clearRect(0,0,W,H);
  fctx.putImageData(img,0,0);
  window.__frames.push(frameCanvas.toDataURL("image/png"));
  await new Promise(r=>setTimeout(r,0));
}
fxRT.dispose();

// ==================== PREVIEW ====================
status.textContent="Done! Previewing...";

const preview=document.createElement("canvas");
preview.width=W*2;preview.height=H*2;
preview.style.cssText="display:block;margin:20px auto;border:1px solid #333;background:#000;image-rendering:pixelated";
document.body.appendChild(preview);
const pctx=preview.getContext("2d");
pctx.imageSmoothingEnabled=false;

// Preload frame images
const frameImgs=[];
for(const dataUrl of window.__frames){
  const img=new Image();
  img.src=dataUrl;
  await new Promise(r=>{img.onload=r;});
  frameImgs.push(img);
}

const info=document.createElement("div");
info.style.cssText="text-align:center;color:#888;font-family:monospace;font-size:14px;margin:10px";
info.textContent=`${W}x${H}px per frame | ${FRAMES} frames @ 24fps | Lightning Smite`;
document.body.appendChild(info);

let frame=0;
function animate(){
  pctx.clearRect(0,0,preview.width,preview.height);
  pctx.drawImage(frameImgs[frame],0,0,preview.width,preview.height);
  frame=(frame+1)%FRAMES;
  setTimeout(()=>requestAnimationFrame(animate),42); // 24fps
}
animate();

window.__done=true;
</script>
<style>
body{background:#111;color:#ccc;font-family:monospace;text-align:center}
#status{padding:30px;font-size:18px;color:#aaa}
</style>
</body></html>