import assert from 'node:assert/strict';
import * as R from './mesh-refraction-reference.mjs';
const {v3,makeDepthTexture,depthAt,photoSurface,triangleOracle,tracePhotoDDA}=R;
const F=Math.fround,A=(a,b)=>F(a+b),S=(a,b)=>F(a-b),M=(a,b)=>F(a*b),D=(a,b)=>F(a/b),V=a=>a.map(F),add=(a,b)=>a.map((x,i)=>A(x,b[i])),sub=(a,b)=>a.map((x,i)=>S(x,b[i])),mul=(a,b)=>a.map(x=>M(x,b)),dot=(a,b)=>A(A(M(a[0],b[0]),M(a[1],b[1])),M(a[2],b[2])),cross=(a,b)=>[S(M(a[1],b[2]),M(a[2],b[1])),S(M(a[2],b[0]),M(a[0],b[2])),S(M(a[0],b[1]),M(a[1],b[0]))],INF=F(1e20);
function triangle(o,r,a,b,c){let e1=sub(b,a),e2=sub(c,a),p=cross(r,e2),det=dot(e1,p);if(det<=F(1e-9))return INF;let s=sub(o,a),u=D(dot(s,p),det);if(u<F(-.00001)||u>F(1.00001))return INF;let q=cross(s,e1),v=D(dot(r,q),det);if(v<F(-.00001)||A(u,v)>F(1.00001))return INF;let t=D(dot(e2,q),det);return t>=0?t:INF;}
function shaderDDA(surface,origin,ray){const o=V(origin.toArray()),r=V(ray.toArray());let near=0,far=INF;const bounds=[[-.5,.5],[-.5,.5],[0,.25]];for(let i=0;i<3;i++){let [lo,hi]=bounds[i];if(Math.abs(r[i])<F(1e-9)){if(!(o[i]>=lo&&o[i]<=hi))return null;}else{let a=D(S(lo,o[i]),r[i]),b=D(S(hi,o[i]),r[i]);near=Math.max(near,Math.min(a,b));far=Math.min(far,Math.max(a,b));if(far<near)return null;}}
let p=add(o,mul(r,near)),direction=r.slice(0,2).map(Math.sign),cell=p.slice(0,2).map((v,i)=>Math.min(127,Math.max(0,Math.floor(A(M(A(v,.5),128),M(direction[i],.00001)))))),next=[INF,INF],delta=[INF,INF];for(let i=0;i<2;i++)if(Math.abs(r[i])>=F(1e-9)){next[i]=D(S(S(D(A(cell[i],r[i]>=0?1:0),128),.5),o[i]),r[i]);delta[i]=D(1,M(128,Math.abs(r[i])));}
const vert=(x,y)=>[S(D(x,128),.5),S(D(y,128),.5),M(F(depthAt(surface.texture,D(x,128),D(y,128))),.25)];
for(let i=0;i<257;i++){let ll=vert(cell[0],cell[1]),lr=vert(A(cell[0],1),cell[1]),ul=vert(cell[0],A(cell[1],1)),ur=vert(A(cell[0],1),A(cell[1],1));let t=Math.min(triangle(o,r,ul,ll,ur),triangle(o,r,ll,lr,ur)),end=Math.min(far,...next);if(t>=S(near,.00001)&&t<=A(end,.00001)&&t<F(1e19))return{t,point:add(o,mul(r,t)),cells:i+1};if(end>=S(far,.000001))return null;let cx=next[0]<=next[1],cy=next[1]<=next[0];near=end;if(cx){cell[0]=A(cell[0],direction[0]);next[0]=A(next[0],delta[0]);}if(cy){cell[1]=A(cell[1],direction[1]);next[1]=A(next[1],delta[1]);}if(cell.some(v=>v<0||v>=128))return null;}throw Error('257 cells exhausted');}
const surface=photoSurface(makeDepthTexture(67,53,(x,y)=>.5+.21*Math.sin(x*1.2)+.25*Math.cos(y*.9+x*.4)));
let seed=0x5eed,random=()=>{seed=(Math.imul(seed,1664525)+1013904223)>>>0;return seed/2**32;},cases=[];
for(let i=0;i<1500;i++){const o=v3((random()-.5)*1.8,(random()-.5)*1.8,.4+random()),target=v3((random()-.5)*1.2,(random()-.5)*1.2,random()*.2);cases.push([o,target.sub(o).normalize()]);}
for(const x of [-.5,-.25,0,.25,.5])for(const y of [-.5,-.25,0,.25,.5])for(const dx of [-.3,0,.3])for(const dy of [-.3,0,.3])cases.push([v3(x,y,1),v3(dx,dy,-1).normalize()]);
for(let i=0;i<20;i++)cases.push([v3(-.6,-.45+i*.02,.249),v3(1,.85,-.0001).normalize()]);
let misses=0,worst=0,maxcells=0;
for(let i=0;i<cases.length;i++){const [o,r]=cases[i],actual=shaderDDA(surface,o,r),expected=tracePhotoDDA(surface,o,r).hit;assert.equal(Boolean(actual),Boolean(expected),`hit/miss ray ${i}`);if(actual){const error=v3(...actual.point).distanceTo(expected.point);worst=Math.max(worst,error);maxcells=Math.max(maxcells,actual.cells);assert.ok(error<.0001,`ray ${i} error ${error}`);}else misses++;if(i<40){const oracle=triangleOracle(surface,o,r);assert.equal(Boolean(actual),Boolean(oracle));}}
console.log(JSON.stringify({kind:'CPU Float32 arithmetic mirror of production DDA and Moller triangles; not GPU',rays:cases.length,misses,worstHitPointError:worst,maxcells}));
const longSurface=photoSurface(makeDepthTexture(2,2,(x,y)=>x*y));let longWorst=0,longMax=0,longCases=0;
for(let i=0;i<80;i++){const o=v3(-.6,-.45+i*.005,.249),r=v3(1,.85,-.0001).normalize(),a=shaderDDA(longSurface,o,r),e=tracePhotoDDA(longSurface,o,r).hit;assert.equal(Boolean(a),Boolean(e),`long ray ${i}`);if(a){longMax=Math.max(longMax,a.cells);longWorst=Math.max(longWorst,v3(...a.point).distanceTo(e.point));assert.ok(v3(...a.point).distanceTo(e.point)<.0001);}longCases++;}
console.log(JSON.stringify({kind:'CPU Float32 long XY traversal',rays:longCases,worstHitPointError:longWorst,maxcells:longMax}));