WIP: landing

html/images/space.svg

@@ -292,6 +292,9 @@ const map = (function(els) {
 let allStartingEdges;
 init();
 
+const b = map.edges.map(({ edge }) => getEdgeCollisionBoundary(edge, shipRadius));
+b.forEach(b => drawLine(b.xa, b.ya, b.xb, b.yb, "orange"));
+
 function distance(x1, y1, x2, y2) {
   return Math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2);
 }
@@ -540,23 +543,28 @@ function isLandable(edge) {
   // return Object.is(slope(edge), +0);
 }
 
-function detectEdgeCollision([xc, yc], [x, y], radius) {
+function getEdgeCollisionBoundary(edge, dist) {
+  const { xa, ya, xb, yb } = edge;
+  const length = distance(xa, ya, xb, yb);
+  const rise = yb - ya;
+  const run = xb - xa;
+
+  const riol = rise / length * dist;
+  const ruol = run / length * dist;
+
+  return { xa: xa + riol, ya: ya - ruol, xb: xb + riol, yb: yb - ruol};
+}
+
+function detectEdgeCollision([xc, yc], [x, y], radius, gearDown = false) {
   return ({ edge, wall }) => {
     if (xc === x && yc === y) return;
 
-    const { xa, ya, xb, yb } = edge;
-    const length = distance(xa, ya, xb, yb);
-    const rise = yb - ya;
-    const run = xb - xa;
-
-    const riol = rise / length * radius;
-    const ruol = run / length * radius;
-
+    const dist = edge.x3 < edge.x4 && edge.y3 === edge.y4 && gearDown ? radius + 2 : radius;
+    const edgeSeg = getEdgeCollisionBoundary(edge, dist);
     const positionSeg = { xa: x, ya: y, xb: xc, yb: yc };
-    const edgeSeg = { xa: xa + riol, ya: ya - ruol, xb: xb + riol, yb: yb - ruol};
 
-    const { xa: x1, ya: y1, xb: x2, yb: y2 } = positionSeg;
-    const { xa: x3, ya: y3, xb: x4, yb: y4 } = edgeSeg;
+    let { xa: x1, ya: y1, xb: x2, yb: y2 } = positionSeg;
+    let { xa: x3, ya: y3, xb: x4, yb: y4 } = edgeSeg;
 
     // https://en.wikipedia.org/wiki/Intersection_(geometry)#Two_line_segments
     // https://en.wikipedia.org/wiki/Cramer%27s_rule#Explicit_formulas_for_small_systems
@@ -618,12 +626,12 @@ function detectCornerCollision([xc, yc], [x, y], radius) {
   };
 }
 
-function detectCollision(currentPos, intendedPos, velocity, radius, { edges, corners }) {
+function detectCollision(currentPos, intendedPos, velocity, radius, { edges, corners }, gearDown) {
   const { x: xc, y: yc } = intendedPos;
   const [x, y] = currentPos;
   // edges oriented clockwise with ship
   const fwdEdges = getForwardEdges(edges, { x, y })
-  const edgeColl = fwdEdges.find(detectEdgeCollision([xc, yc], [x, y], radius));
+  const edgeColl = fwdEdges.find(detectEdgeCollision([xc, yc], [x, y], radius, gearDown));
 
   if (edgeColl) return edgeColl;
 
@@ -669,12 +677,16 @@ function cornerContactPosition(xc, yc, x, y, corner, cLength) {
   return intxnSeg.getPointAtLength(bLength);
 }
 
-function edgeContactPosition(xc, yc, x, y, edge, radius) {
+function edgeContactPosition(xc, yc, x, y, edge, radius, gearDown) {
   const baseSlope = slope(edge);
-  // if (Object.is(baseSlope, 0)) s.isLanded = true;
   let { xa, ya, xb, yb } = edge;
   const positionSeg = { x1: x, y1: y, x2: xc, y2: yc };
-  const edgeSeg = { x1: xa, y1: ya, x2: xb, y2: yb };
+  // const edgeSeg = { x1: xa, y1: ya, x2: xb, y2: yb };
+  const dist = isLandable(edge) && gearDown ? radius + 2 : radius;
+  const b = getEdgeCollisionBoundary(edge, dist);
+  const edgeSeg = { x1: b.xa, y1: b.ya, x2: b.xb, y2: b.yb };
+
+  console.log("DIST", dist, "edge", edge, "edgeSeg", edgeSeg);
 
   const baseNrmlIntxn = perpIntxn(baseSlope, xa, ya, x, y);
   const basePosIntxn = lineIntxnPt(edgeSeg, positionSeg);
@@ -683,7 +695,7 @@ function edgeContactPosition(xc, yc, x, y, edge, radius) {
   const normalSegLength = distance(baseNrmlIntxn.x, baseNrmlIntxn.y, x, y);
 
   const theta = Math.atan(normalSegLength / baseSegLength);
-  const h = radius / Math.sin(theta);
+  const h = dist / Math.sin(theta);
 
   const cl = document.createElementNS(namespaceURIsvg, 'line');
   cl.setAttribute('x1', basePosIntxn.x);
@@ -734,7 +746,7 @@ function updateShip(s, elapsed) {
   const p = { x: pDelta.x + px, y: pDelta.y + py };
   current = s.collision;
 
-  s.collision = detectCollision([px, py], p, s.velocity, shipRadius, map);
+  s.collision = detectCollision([px, py], p, s.velocity, shipRadius, map, s.gearDown);
   if (s.collision) console.log("COLLISION", s.collision);
 
   legs.style.display = s.gearDown ? "initial" : "none";
@@ -744,13 +756,13 @@ function updateShip(s, elapsed) {
     // edge is facing up or down? compare xs?
 
     // 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(p.x, p.y, px, py, s.collision.corner, shipRadius);
     } else if (s.collision.edge) {
-      posP = edgeContactPosition(p.x, p.y, px, py, s.collision.edge, shipRadius);
+      if (isLandable(s.collision.edge) && s.gearDown) s.isLanded = true;
+      posP = edgeContactPosition(p.x, p.y, px, py, s.collision.edge, shipRadius, s.gearDown);
     }
 
     s.velocity = { x: 0, y: 0 };
@@ -759,7 +771,7 @@ function updateShip(s, elapsed) {
   } else if (current && s.collision) {
     s.velocity = { x: 0, y: 0 };
   } else {
-    if (s.isLanded) {
+    if (s.isLanded && s.velocity.y < 0) {
       s.gearDown = false;
       s.isLanded = false;
     }