From 89cf20e35a47014591b652bd32f7e2164681f7b2 Mon Sep 17 00:00:00 2001
From: Catalin Constantin Mititiuc <webdevcat@proton.me>
Date: Fri, 30 Jan 2026 13:25:51 -0800
Subject: [PATCH] WIP: more rounding

---
 html/images/space.svg | 164 ++++++++++++++++++++++++++++--------------
 1 file changed, 112 insertions(+), 52 deletions(-)

diff --git a/html/images/space.svg b/html/images/space.svg
index a376ae3..df5be83 100644
--- a/html/images/space.svg
+++ b/html/images/space.svg
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<svg viewBox="-200 -150 400 300" version="1.1" xmlns="http://www.w3.org/2000/svg">
-<!-- <svg viewBox="-10 -10 100 100" version="1.1" xmlns="http://www.w3.org/2000/svg"> -->
+<!-- <svg viewBox="-200 -150 400 300" version="1.1" xmlns="http://www.w3.org/2000/svg"> -->
+<svg viewBox="-20 -20 30 30" version="1.1" xmlns="http://www.w3.org/2000/svg">
   <style>
     foreignObject {
       font-size: 4pt;
@@ -129,7 +129,7 @@
   <!-- <polygon class="wall" points="-10,-40 10,-40 10,-20 -10,-20" /> -->
 
   <!-- <polygon class="wall" points="-10,-40 10,-40 10,-15 -10,-15" /> -->
-  <!-- <polygon class="wall" points="-20,-10 20,10 -10,100 -100,100" /> -->
+  <polygon class="wall" points="-20,-10 20,10 -10,100 -100,100" />
 
   <!-- <polygon class="wall" points="-10,10 10,30 -10,40 -20,20" /> -->
   <!-- <polygon class="wall" points="-20,-10 0,10 -20,20 -30,0" /> -->
@@ -241,13 +241,13 @@ const Move = (() => {
     // https://en.wikipedia.org/wiki/Curve_orientation#Practical_considerations
     // Determinant for a convex polygon
     const det = (xb - xa) * (yc - ya) - (xc - xa) * (yb - ya);
-    console.log("xa, ya, xb, yb, xc, yc", xa, ya, xb, yb, xc, yc);
+    // console.log("xa, ya, xb, yb, xc, yc", xa, ya, xb, yb, xc, yc);
     const detEx = (xb*expo - xa*expo) * (yc*expo - ya*expo) - (xc*expo - xa*expo) * (yb*expo - ya*expo);
-    console.log("=----", xb*expo - xa*expo,  yc*expo - ya*expo, xc*expo - xa*expo,  yb*expo - ya*expo);
-    console.log("=----", xb*expo, xa*expo,  yc*expo, ya*expo, xc*expo, xa*expo,  yb*expo, ya*expo);
-    console.log("=----", xb*expo - xa*expo,  yc*expo - ya*expo, xc*expo - xa*expo,  yb*expo - ya*expo);
-    console.log("=----", (xb*expo - xa*expo) * (yc*expo - ya*expo), (xc*expo - xa*expo) * (yb*expo - ya*expo));
-    console.log("detxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", detEx * 1e-16);
+    // console.log("=----", xb*expo - xa*expo,  yc*expo - ya*expo, xc*expo - xa*expo,  yb*expo - ya*expo);
+    // console.log("=----", xb*expo, xa*expo,  yc*expo, ya*expo, xc*expo, xa*expo,  yb*expo, ya*expo);
+    // console.log("=----", xb*expo - xa*expo,  yc*expo - ya*expo, xc*expo - xa*expo,  yb*expo - ya*expo);
+    // console.log("=----", (xb*expo - xa*expo) * (yc*expo - ya*expo), (xc*expo - xa*expo) * (yb*expo - ya*expo));
+    // console.log("detxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", detEx * 1e-16);
 
     // (8.0046e+33) / 1e30
     // -> 8004.599999999999
@@ -272,7 +272,7 @@ const Move = (() => {
 
 
     // console.log(xb, xa, yc, ya, xc, xa, yb, ya);
-    console.log("dettttttttttttttttttttt", det);
+    // console.log("dettttttttttttttttttttt", det);
     return det < 0;
   }
 
@@ -385,25 +385,62 @@ const Move = (() => {
       // console.log("x2", x2, "x1", x1, "y4", y4, "y3", y3, "x4", x4, "x3", x3, "y2", y2, "y1", y1);
 
       // console.log("denom", denom);
-      const x21 = +(x2-x1).toPrecision(13);
-      const y43 = +(y4-y3).toPrecision(13);
-      const x43 = +(x4-x3).toPrecision(13);
-      const y21 = +(y2-y1).toPrecision(13);
-      const denom = +(x21*y43-x43*y21).toPrecision(13);
-      const x31 = +(x3-x1).toPrecision(13);
-      const y31 = +(y3-y1).toPrecision(13);
+      // const x21 = +(x2-x1).toPrecision(13);
+      // const y43 = +(y4-y3).toPrecision(13);
+      // const x43 = +(x4-x3).toPrecision(13);
+      // const y21 = +(y2-y1).toPrecision(13);
+      // const denom = +(x21*y43-x43*y21).toPrecision(13);
+      // const x31 = +(x3-x1).toPrecision(13);
+      // const y31 = +(y3-y1).toPrecision(13);
 
-      console.log("DENOM", denom);
+      const subR = (a, b) => Math.round(a * 100 - b * 100) / 100;
 
-      if (denom) {
+      const x21 = x2-x1;
+      const x21r = subR(x2, x1);
+      // Math.round(3.8 * 100 - 3.74 * 100) / 100
+
+      const y43 = y4-y3;
+      const y43r = subR(y4, y3);
+
+      const x43 = x4-x3;
+      const x43r = subR(x4, x3);
+
+      const y21 = y2-y1;
+      const y21r = subR(y2, y1);
+
+      const denom = x21*y43-x43*y21;
+      const denomr = Math.round(x21r*100*y43r-x43r*y21r*100) / 100;
+
+      console.log("denom", denom);
+      console.log("denomr", denomr, x21r, y43r, x43r, y21r);
+
+      const x31 = x3-x1;
+      const x31r = subR(x3, x1);
+
+      const y31 = y3-y1;
+      const y31r = subR(y3, y1);
+
+      // console.log("x2", x2, " - ", "x1", x1, "=", x2-x1);
+
+      // console.log(x21, y43, x43, y21, denom, x31, y31);
+
+
+      // if (denom) {
+      if (denomr) {
         // const s = ((x3-x1)*(y4-y3)-(x4-x3)*(y3-y1))/denom;
         // const t = -((x2-x1)*(y3-y1)-(x3-x1)*(y2-y1))/denom;
         // const roundedT = +t.toFixed(2);
         // const roundedS = +s.toFixed(2);
         // const roundedT = +t.toFixed(15);
         // const roundedS = +s.toFixed(15);
-        const s = +(+(x31*y43-x43*y31).toPrecision(13) / denom).toPrecision(13);
-        const t = +(-(x21*y31-x31*y21).toPrecision(13) / denom).toPrecision(13);
+        // const s = +(+(x31*y43-x43*y31).toPrecision(13) / denom).toPrecision(13);
+        // const t = +(-(x21*y31-x31*y21).toPrecision(13) / denom).toPrecision(13);
+        const s = (x31*y43-x43*y31) / denom;
+        const t = -(x21*y31-x31*y21) / denom;
+        const sr = (x31r*y43r-x43r*y31r) / denomr;
+        const tr = (-(x21r*y31r*100*100-x31r*y21r*100*100) / denomr)/10000;
+
+        console.log(x21r, y31r, x31r, y21r, denomr);
 
         // console.log("checking edge for collision", edge);
         // console.log("position edge segs", positionSeg, edgeSeg);
@@ -413,15 +450,35 @@ const Move = (() => {
         // console.log("position seg", positionSeg);
         // console.log("s", s, "roundedS", roundedS, "t", t, "roundedT", roundedT);
         console.log("s", s, "t", t);
+        console.log("sr", sr, "tr", tr);
+
+        // 2.03 * 10
+        // 20.299999999999997
 
         // if (roundedS >= 0 && roundedS <= 1 && roundedT >= 0 && roundedT <= 1) {
-        if (s >= 0 && s < 1 && t >= 0 && t <= 1) { // this falls through
-        // if (s >= 0 && s <= 1 && t >= 0 && t <= 1) { // this sometimes falls through
-          const xs = +((x1 + s * +(x2 - x1).toPrecision(13))).toPrecision(13);
-          const ys = +((y1 + s * +(y2 - y1).toPrecision(13))).toPrecision(13);
-          console.log("xs", xs, "ys", ys);
+        // if (s >= 0 && s < 1 && t >= 0 && t <= 1) { // this falls through
+        if (s >= 0 && s <= 1 && t >= 0 && t <= 1) { // this sometimes falls through
+          // const xs = x1 + s * (x2 - x1);
+          // const ys = y1 + s * (y2 - y1);
 
-          collision.position = { x: xs, y: ys };
+          const xs = x1 + s * (x2 - x1);
+          const ys = y1 + s * (y2 - y1);
+
+          // Math.round(Math.round(-2.03 * 100) + 0.45000000000000445 * (Math.round(-1.95 * 100) - Math.round(-2.03 * 100))) / 100
+          // console.log("xs", xs, "ys", ys);
+          console.log("x1", x1, "x2", x2);
+          console.log("y1", y1, "y2", y2);
+
+          const x1r = Math.round(x1 * 100);
+          const x2r = Math.round(x2 * 100);
+          const y1r = Math.round(y1 * 100);
+          const y2r = Math.round(y2 * 100);
+
+          const xsr = Math.round(x1r + s * (x2r - x1r)) / 100;
+          const ysr = Math.round(y1r + s * (y2r - y1r)) / 100;
+
+          // collision.position = { x: xs, y: ys };
+          collision.position = { x: xsr, y: ysr };
 
           // console.log("xs, yx", xs, ys);
           // console.log("xc, yc", xc, yc);
@@ -628,9 +685,9 @@ const Move = (() => {
       };
 
       console.log("----------elapsed", elapsed)
-      console.log("velocity", v);
-      console.log("current position", px, py);
-      console.log("future position", p);
+      // console.log("velocity", v);
+      // console.log("current position", px, py);
+      // console.log("future position", p);
       // console.log("px + elapsed * 1000 * v.x / 1000", px + elapsed * 1000 * v.x / 1000 / 1000);
       // 0.57 * 1000 * 20 / 1000
 
@@ -675,8 +732,8 @@ const Move = (() => {
         } else if (contact.edge) {
           // if (isLandable(contact.edge) && s.gearDown) s.isLanded = true;
           const accVect = vector(ax, ay);
-          const rise = (contact.edge.yb-contact.edge.ya).toPrecision(16);
-          const run = (contact.edge.xb-contact.edge.xa);
+          const rise = contact.edge.yb-contact.edge.ya;
+          const run = contact.edge.xb-contact.edge.xa;
           const edgeNrmlVect = vector(rise, -run);
           const velocityVect = vector(v.x, v.y);
 
@@ -708,14 +765,19 @@ const Move = (() => {
           // drawLine(contact.position.x, contact.position.y, contact.position.x + prVonNx, contact.position.y + prVonNy, "teal");
 
           const side = isClockwise([contact.edge.xa, contact.edge.ya], [contact.edge.xb, contact.edge.yb], [px, py]);
-          console.log("Side of edge I'm on", side < 0 ? "side A" : "side B");
 
           // contact.velocity = { x: prVonNx, y: prVonNy };
-          Velocity[entity_id] = { x: prVonNx, y: prVonNy };
-          console.log("contact.position", contact.position);
-          // drawCircle(contact.position.x, contact.position.y);
+          Velocity[entity_id] = { x: -prVonNx, y: -prVonNy };
+          console.log("velocity", Velocity[entity_id]);
+
           console.log("current position", px, py);
-          console.log("future position", p);
+          drawCircle(px, py, "pink");
+
+          console.log("contact.position", contact.position);
+          drawCircle(contact.position.x, contact.position.y, "limegreen");
+
+          console.log("intended next position", p);
+          drawCircle(p.x, p.y, "red");
 
           // const newV = {
           //   x: vx > 0 && vx + ax <= 0 ? 0 : vx + ax,
@@ -723,14 +785,14 @@ const Move = (() => {
           // };
 
           const newP = {
-            x: contact.position.x + elapsed * prVonNx * metersPerMillisecond,
-            y: contact.position.y + elapsed * prVonNy * metersPerMillisecond
+            // x: contact.position.x + elapsed * prVonNx * metersPerMillisecond,
+            // y: contact.position.y + elapsed * prVonNy * metersPerMillisecond
+            x: Math.round((contact.position.x + elapsed * prVonNx * metersPerMillisecond) * 100) / 100,
+            y: Math.round((contact.position.y + elapsed * prVonNy * metersPerMillisecond) * 100) / 100,
           };
 
-          newP.x = +newP.x.toPrecision(13);
-          newP.y = +newP.y.toPrecision(13);
-          console.log("newP", newP);
-          drawCircle(newP.x, newP.y, "red", 0.1);
+          console.log("actual next position", newP);
+          drawCircle(newP.x, newP.y, "black");
 
           Position[entity_id] = newP;
         }
@@ -824,17 +886,17 @@ function init() {
   const mult = 10;
 
   s.position = { x: 0, y: -10 };
-  // s.velocity = { x: -10, y: 20 };
+  s.velocity = { x: 0, y: 0 };
   // s.velocity = { x: 10, y: 20 };
   // s.velocity = { x: -20, y: 40 };
-  s.velocity = { x: -1, y: 2 };
+  // s.velocity = { x: -1, y: 2 };
   s.angularVelocity = 0;
 
   // s. velocity = { x: -5*mult, y: 7*mult };
   // drawCircle(0, 0);
 
-  // s.acceleration = { x: 1, y: 3 };
-  s.acceleration = { x: 0, y: 0 };
+  s.acceleration = { x: -1, y: 2 };
+  // s.acceleration = { x: 0, y: 0 };
 
   Ships.forEach(({ entity_id }) => {
     // Acceleration[entity_id] = s.acceleration;
@@ -1137,7 +1199,7 @@ function drawLine(xa, ya, xb, yb, color = "black") {
   return el;
 }
 
-function drawCircle(cx, cy, color = "black", r = 1) {
+function drawCircle(cx, cy, color = "black", r = 0.2) {
   const el = document.createElementNS(namespaceURIsvg, 'circle');
   el.setAttribute('cx', cx);
   el.setAttribute('cy', cy);
@@ -1563,10 +1625,8 @@ function animate(timestamp) {
   newVel = Velocity[Ships[0].entity_id];
 
   s.node.style.transform = `translate(${newPos.x}px, ${newPos.y}px)`;
-  // s.node.style.transform = `translate(${Math.round(newPos.x)}px, ${Math.round(newPos.y)}px)`;
-  // console.log("translation", s.node.style.transform);
-  positionEl.innerText = `${newPos.x.toFixed(1)},${newPos.y.toFixed(1)}`;
-  velocityEl.innerText = `${newVel.x.toFixed(1)},${newVel.y.toFixed(1)}`;
+  positionEl.innerText = `${newPos.x},${newPos.y}`;
+  velocityEl.innerText = `${newVel.x},${newVel.y}`;
 
   // updateEdges(position);
   if (drawCollisionLines) updateTriangles(position);