Rotate gun with torque and angular acceleration/velocity

html/images/space.svg

@@ -285,7 +285,6 @@ const map = (function(els) {
 })(wallElements);
 
 let allStartingEdges;
-let friction = 0;
 let rotationSpeed = 0.25;
 let started = false;
 let restart = false;
@@ -297,10 +296,12 @@ function init() {
 
   s.position = { x: 10, y: 10 };
   s.velocity = { x: 0, y: 0 };
+  s.angularVelocity = 0;
 
   // s. velocity = { x: -5*mult, y: 7*mult };
 
   s.acceleration = { x: 0, y: 0 };
+  s.angularAcceleration = 0;
   s.rotate = 0;
   s.degrees = 0;
   s.collision = null;
@@ -787,11 +788,11 @@ function lineIntxnPt({ x1, y1, x2, y2 }, { x1: x3, y1: y3, x2: x4, y2: y4 }) {
 function updateShip(s, elapsed) {
   const gravity = 0.25;
 
-  if (rotate > 0) {
+  // if (rotate > 0) {
-    s.degrees = (s.degrees + rotationSpeed * elapsed) % 360;
+  //   s.degrees = (s.degrees + rotationSpeed * elapsed) % 360;
-  } else if (rotate < 0) {
+  // } else if (rotate < 0) {
-    s.degrees = (s.degrees - rotationSpeed * elapsed) % 360;
+  //   s.degrees = (s.degrees - rotationSpeed * elapsed) % 360;
-  }
+  // }
 
   gun.style.transform = `rotate(${s.degrees}deg)`;
 
@@ -799,6 +800,9 @@ function updateShip(s, elapsed) {
   const { x: vx, y: vy } = s.velocity;
   // const { x: ax, y: ay } = s.acceleration;
   let { x: ax, y: ay } = s.acceleration;
+  const angularVel = s.angularVelocity;
+  const angularAcc = s.angularAcceleration;
+  const degrees = s.degrees;
   ay += gravity;
 
   s.velocity = {
@@ -806,6 +810,16 @@ function updateShip(s, elapsed) {
     y: vy > 0 && vy + ay <= 0 ? 0 : vy + ay
   };
 
+  s.angularVelocity = angularVel + angularAcc;
+
+  const friction = 0.05;
+
+  if (s.angularVelocity > 0) {
+    s.angularVelocity -= s.angularVelocity > friction ? friction : s.angularVelocity;
+  } else if (s.angularVelocity < 0) {
+    s.angularVelocity += -s.angularVelocity > friction ? friction : -s.angularVelocity;
+  }
+
   velIndic.setAttribute('x2', s.velocity.x);
   velIndic.setAttribute('y2', s.velocity.y);
   acclIndic.setAttribute('x2', s.acceleration.x);
@@ -819,6 +833,12 @@ function updateShip(s, elapsed) {
   };
 
   const p = { x: pDelta.x + px, y: pDelta.y + py };
+
+  const turnRadians = elapsed * s.angularVelocity * metersPerMillisecond;
+  const radians = degrees * Math.PI / 180; // toFixed(15)?
+  const dDelta = turnRadians * 180 / Math.PI;
+
+  s.degrees = degrees + dDelta;
   current = s.collision;
 
   // const tempRadius = 7;
@@ -979,6 +999,7 @@ function animate(timestamp) {
 }
 
 let force = 1;
+let torque = 0.1;
 let spacePressed = false;
 let restartPressed = false;
 let upPressed = false;
@@ -1036,14 +1057,14 @@ document.addEventListener("keydown", function(e) {
     case "Comma":
       if (!rotateCCWPressed) {
         rotateCCWPressed = true;
-        rotate += -1;
+        s.angularAcceleration -= torque;
       }
       break;
     case "KeyE":
     case "Period":
       if (!rotateCWPressed) {
         rotateCWPressed = true;
-        rotate += 1;
+        s.angularAcceleration += torque;
       }
       break;
     case "KeyP": // Pause
@@ -1096,14 +1117,14 @@ document.addEventListener("keyup", function(e) {
     case "Comma":
       if (rotateCCWPressed) {
         rotateCCWPressed = false;
-        rotate -= -1;
+        s.angularAcceleration += torque;
       }
       break;
     case "KeyE":
     case "Period":
       if (rotateCWPressed) {
         rotateCWPressed = false;
-        rotate -= 1;
+        s.angularAcceleration -= torque;
       }
       break;
   }