From 5c5c76f9a1df3ee154e6d4d727988eae2b5bafa2 Mon Sep 17 00:00:00 2001
From: Catalin Constantin Mititiuc <webdevcat@proton.me>
Date: Wed, 7 Jan 2026 12:58:06 -0800
Subject: [PATCH] Clean up

---
 html/images/space.svg | 135 ++++++++++++++++++++++--------------------
 1 file changed, 72 insertions(+), 63 deletions(-)

diff --git a/html/images/space.svg b/html/images/space.svg
index 338ec15..53f4440 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 60 60" 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="-10 -10 100 100" version="1.1" xmlns="http://www.w3.org/2000/svg">
   <style>
     foreignObject {
       font-size: 4pt;
@@ -186,6 +186,24 @@
   </foreignObject>
 
   <script type="text/javascript">//<![CDATA[
+    // entities
+    // const Ships = [{ entity_id: "ship_1" }];
+    // const Walls = [{ entity_id: "wall_1" }, { entity_id: "wall_2" }];
+
+    // systems
+    // Move.update = ({ entity_id }) => {
+      // reads Velocity[entity_id]
+      // sets Position[entity_id]
+    // };
+
+    // components
+    // Velocity = { "ship_1": { x: 0, y: 0 }};
+    // Position = { "ship_1": { x: 0, y: 0 }};
+    // Points = {
+    //   "wall_1": "0,0 2,0 1,1",
+    //   "wall_2": "0,0 -1,1 -2,0",
+    // };
+
     const namespaceURIsvg = 'http://www.w3.org/2000/svg';
     const degsRegex = /(-?\d*\.{0,1}\d+)deg/g;
     const regex = /(-?\d*\.{0,1}\d+)px/g;
@@ -208,11 +226,11 @@
 
     const s = {
       position: { x: 0, y: 0 },
-      velocity: { x: 0, y: 0 },
+      // velocity: { x: 0, y: 0 },
       // velocity: { x: -100, y: -100 },
 
-      // velocity: { x: 5, y: 7 },
-      // velocity: { x: 5*mult, y: 8*mult },
+      // velocity: { x: 2, y: 7 },
+      velocity: { x: 2*mult, y: 7*mult },
       // acceleration: { x: 5, y: 7 },
       acceleration: { x: 0, y: 0 },
       rotate: 0,
@@ -271,25 +289,11 @@
       });
 
       const edges = corners.map(({ x: xa, y: ya }, i, arr) => {
-        // return [+x, +y];
-        // const [xb, yb] = arr[i]++;
         const { x: xb, y: yb } = arr[(i + 1) % arr.length];
-        // console.log("coords", { xa: +x, ya: +y, xb: +xb, yb: +yb, inverse: wall.classList.contains("inverse") });
-
-        // return `${+x},${+y} ${+xb},${+yb}`;
-        return {
-          xa: xa,
-          ya: ya,
-          xb: xb,
-          yb: yb,
-        };
+        return { xa: xa, ya: ya, xb: xb, yb: yb };
       });
 
-      return {
-        node,
-        corners,
-        edges
-      };
+      return { node, corners, edges };
     });
 
     const mcs = ws.reduce(
@@ -389,40 +393,15 @@
       }, []);
     }
 
-    function getCollisionEdges(walls, [xc, yc]) {
-      return walls.reduce((acc, wall) => {
-        return [...acc, ...wall.edges.filter(({ xa, ya, xb, yb }) => {
-          return [isClockwise, isAcute].every(c => c([xa, ya], [xb, yb], [xc, yc]));
-        }).map(edge => ({ edge, wall }))];
-      }, []);
+    function getForwardEdges(edges, { x, y }) {
+      return edges.filter(({ edge }) => {
+        const { xa, ya, xb, yb } = edge;
+        const det = (xb - xa) * (y - ya) - (x - xa) * (yb - ya);
+        return det < 0;
+      });
     }
 
-    // function getCollisionCorners(ws, { x: px, y: py }, { x: vx, y: vy }) {
-    function getCollisionCorners(ws, { x: x1, y: y1 }, { x: x2, y: y2 }) {
-      const diffx = x2;
-      const diffy = y2;
-      const detv = x2 * y1 - y2 * x1;
-      const dv = Math.sqrt(diffy ** 2 + diffx ** 2);
-      const slopev = slope({ xa: x1, ya: y1, xb: x1 + x2, yb: y1 + y2 });
-
-      return ws.reduce((acc, w) => {
-        const filtered = w.corners.filter(c => {
-          const { x: x0, y: y0 } = c;
-          const velNormIntxn = perpIntxn(slopev, x1, y1, x0, y0);
-          // const d = distance(velNormIntxn.x, velNormIntxn.y , x0, y0);
-
-          // https://en.wikipedia.org/wiki/Distance_from_a_point_to_a_line#Line_defined_by_two_points
-          const d = Math.abs(diffy * x0 - diffx * y0 + detv) / dv;
-          // console.log("corner", c, "d", d, "shipRadius", shipRadius);
-          return d <= shipRadius;
-        }).map(c => ({ corner: c, node: w.node }));
-        // });
-
-        return [...acc, ...filtered];
-      }, []);
-    }
-
-    function getForwardCollisionCorners(walls, position, velocity) {
+    function getForwardCorners(walls, position, velocity) {
       const { x: x1, y: y1 } = position;
       const { x: x2, y: y2 } = velocity;
 
@@ -611,6 +590,16 @@
       return el;
     }
 
+    function drawCircle(cx, cy, color = "black", r = 1) {
+      const el = document.createElementNS(namespaceURIsvg, 'circle');
+      el.setAttribute('cx', cx);
+      el.setAttribute('cy', cy);
+      el.setAttribute('r', r);
+      el.setAttribute('fill', color);
+      svg.appendChild(el);
+      return el;
+    }
+
     function slope({ xa, ya, xb, yb }) {
       return (yb - ya) / (xb - xa);
     }
@@ -645,6 +634,16 @@
         const roundedT = +t.toFixed(2);
         const roundedS = +s.toFixed(2);
 
+        if (roundedS >= 0 && roundedS <= 1 && roundedT >= 0 && roundedT <= 1) {
+          const xs = (x1 + s * (x2 - x1));
+          const ys = (y1 + s * (y2 - y1));
+          const xt = (x3 + t * (x4 - x3));
+          const yt = (y3 + t * (y4 - y3));
+          const collisionPt = [xs, ys];
+          // [xs, ys] === [xt, yt];
+          drawCircle(...collisionPt, "red"); // collision position
+        }
+
         return roundedS >= 0 && roundedS <= 1 && roundedT >= 0 && roundedT <= 1;
       };
     }
@@ -666,12 +665,28 @@
         const { xa: x1, ya: y1, xb: x2, yb: y2 } = positionSeg;
         const { xa: x3, ya: y3, xb: x4, yb: y4 } = cornerSeg;
 
+        drawLine(x1, y1, x2, y2);
+        drawLine(x3, y3, x4, y4);
+
         // https://en.wikipedia.org/wiki/Intersection_(geometry)#Two_line_segments
         // https://en.wikipedia.org/wiki/Cramer%27s_rule#Explicit_formulas_for_small_systems
         const s = ((x3-x1)*(y4-y3)-(x4-x3)*(y3-y1))/((x2-x1)*(y4-y3)-(x4-x3)*(y2-y1));
         const t = -((x2-x1)*(y3-y1)-(x3-x1)*(y2-y1))/((x2-x1)*(y4-y3)-(x4-x3)*(y2-y1));
         const roundedT = +t.toFixed(2);
 
+        if (s >= 0 && roundedT <= 1) {
+          const xs = (x1 + s * (x2 - x1));
+          const ys = (y1 + s * (y2 - y1));
+          const xt = (x3 + roundedT * (x4 - x3));
+          const yt = (y3 + roundedT * (y4 - y3));
+          // [xs, ys] and [xt, yt] should be equal ([xs, ys] === [xy, yt])
+          // (...or about equal, notwithstanding rounding errors)
+          const sCollisionPt = [xs, ys];
+          const tCollisionPt = [xt, yt];
+          drawCircle(...sCollisionPt, "red");
+          drawCircle(...tCollisionPt, "blue");
+        }
+
         return s >= 0 && roundedT <= 1;
       };
     }
@@ -776,22 +791,16 @@
       let [xc, yc] = position;
       // console.log("future position", xc, yc);
 
-      const efs = mes.filter(({ edge, wall }) => {
-        const { xa, ya, xb, yb } = edge;
-        const det = (xb - xa) * (y - ya) - (x - xa) * (yb - ya);
-        return det < 0;
-      });
+      const efs = getForwardEdges(mes, { x, y })
       // console.log("edges facing ship", efs);
 
       const edgeColl = efs.find(detectEdgeCollision([xc, yc], [x, y], shipRadius));
 
       // corners ahead of ship
-      const fCollC = getForwardCollisionCorners(ws, { x, y }, s.velocity);
-      // console.log("corners ahead of ship", fCollC);
+      const fCollC = getForwardCorners(ws, { x, y }, s.velocity);
 
-      // corners within collision distance
+      // corners within collision distance (are on the collision path)
       cwcd = fCollC.filter(withinCollisionDistance({ x, y }, s.velocity));
-      // console.log("corners on collision path", cwcd);
       const cornerColl = cwcd.find(detectCornerCollision([xc, yc], [x, y], shipRadius));
 
       current = s.collision;
@@ -806,7 +815,7 @@
 
         // const baseSlope = slope(s.collision.edge);
         // if (Object.is(baseSlope, 0) && s.gearDown) s.isLanded = true;
-
+        s.isLanded = true;
         let posP;
         if (s.collision.corner) {
           posP = cornerContactPosition(xc, yc, x, y, s.collision.corner, shipRadius);