www/js/animation.ts

@@ -1,5 +1,5 @@
 import { CoupleRole, DancerIdentity, Rotation, normalizeRotation } from "./danceCommon.js";
-import { DancerSetPosition, DancersSetPositions, Hand, OffsetDistance, OffsetEquals, OffsetMinus, OffsetPlus, OffsetRotate, OffsetTimes, OffsetTranspose, offsetZero, setHeight } from "./rendererConstants.js";
+import { DancerSetPosition, DancersSetPositions, Hand, OffsetEquals, OffsetMinus, OffsetPlus, OffsetRotate, OffsetTimes, OffsetTranspose, offsetZero, setHeight } from "./rendererConstants.js";
 import { Offset, leftShoulder, rightShoulder, degreesToRadians, radiansToDegrees } from "./rendererConstants.js";
 
 export enum AnimationKind {
@@ -369,16 +369,17 @@ export class StepWideLinearAnimationSegment extends AnimationSegment {
   private readonly movementAngle: number;
   private readonly handTransitionProgress: number;
   private readonly progressCenter?: number;
+  private readonly center?: Offset;
   private readonly actualCenter: Offset;
   private readonly hands: Map<Hand, HandAnimation>;
   private readonly facing: "Start" | "Forward";
 
-  constructor({ beats, startPosition, endPosition, distanceAtMidpoint, otherPath, hands, facing }: {
+  constructor({ beats, startPosition, endPosition, distanceAtMidpoint, center, hands, facing }: {
     beats: number;
     startPosition: DancerSetPosition;
     endPosition: DancerSetPosition;
     distanceAtMidpoint: number;
-    otherPath?: { start: Offset, end: Offset };
+    center?: Offset;
     hands?: Map<Hand, HandAnimation>;
     facing?: "Start" | "Forward";
   }) {
@@ -402,51 +403,13 @@ export class StepWideLinearAnimationSegment extends AnimationSegment {
     // Center is the point where the dancer is closest to the other dancer.
     //  If omitted, it's assumed the movement is symmetrical, so that happens halfway through the move.
     //  Otherwise, find the point on the line between the start and end closest to the center.
-    this.actualCenter = OffsetPlus(this.startPosition.position, OffsetTimes(vector, 0.5));
+    if (center) {
-    if (otherPath) {
+      this.actualCenter = this.center = center;
-      /*
+      this.progressCenter = ((center.x - this.startPosition.position.x) * vector.x
-(xa(t), ya(t))
+                           + (center.y - this.startPosition.position.y) * vector.y)
-(xb(t), yb(t))
+                           / norm;
-
+    } else {
-(xa_0 + xa_m*t, ya_0, ya_m*t)
+      this.actualCenter = OffsetPlus(this.startPosition.position, OffsetTimes(vector, 0.5));
-(xb_0 + xb_m*t, yb_0, yb_m*t)
-
-
-// can omit the sqrt
-MIN[((xa_0 + xa_m*t) - (xb_0 + xb_m*t))**2 + ((ya_0, ya_m*t) - (yb_0, yb_m*t))**2]
-MIN[(xa_0-xb_0 + (xa_m-xb_m)*t)**2 + (ya_0-yb_0 + (ya_m-yb_m)*t)**2]
-MIN[(x_0 + x_m*t)**2 + (y_0 + y_m*t)**2]
-MIN[(x_0**2 + 2x_0*x_m*t + x_m**2*t**2) + (y_0**2 + 2y_0*y_m*t + y_m**2*t**2)]
-MIN[(x_0**2+y_0**2 + (2x_0*x_m+2y_0*y_m)*t + (x_m**2+y_m**2)*t**2)]
-
-a = x_m**2+y_m**2 = (xa_m-xb_m)**2 + (ya_m-yb_m)**2
-b = (2x_0*x_m+2y_0*y_m) = 2*((xa_0-xb_0)*(xa_m-xb_m) + (ya_0-yb_0)*(ya_m-yb_m))
-
-t = -b/2a
-       */
-      const otherVector = OffsetMinus(otherPath.end, otherPath.start);
-      const m = OffsetMinus(otherVector, vector);
-      const i = OffsetMinus(otherPath.start, this.startPosition.position);
-
-      const a = m.x*m.x + m.y*m.y;
-      const b = 2*(i.x*m.x + i.y*m.y);
-
-      const tMin = -b/(2*a);
-      const t = tMin >= 0 && tMin <= 1 ? tMin : undefined;
-
-      if (t !== undefined) {
-        this.progressCenter = t;
-        this.actualCenter = interpolateLinearOffset(t, this.startPosition.position, this.endPosition.position);
-        const otherCenter = interpolateLinearOffset(t, otherPath.start, otherPath.end);
-        const otherSideways = OffsetMinus(this.actualCenter, otherCenter);
-        const sidewaysLinedUp = Math.sign(otherSideways.x) === Math.sign(sideways.x) && Math.sign(otherSideways.y) === Math.sign(sideways.y);
-        const distanceAdjustment = OffsetDistance(this.actualCenter, otherCenter) * (sidewaysLinedUp ? +1 : -1);
-        if (this.distanceAtMidpoint > 0) {
-          this.distanceAtMidpoint = Math.max(0, this.distanceAtMidpoint - distanceAdjustment);
-        } else {
-          this.distanceAtMidpoint = Math.min(0, this.distanceAtMidpoint + distanceAdjustment);
-        }
-      }
     }
 
     this.handTransitionProgress = 0.5 / beats;

www/js/interpreter.ts

@@ -1066,7 +1066,6 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
             side: hand,
             withHands: true,
             facing: "Start",
-            otherPath: "Swap",
           }
         };
 
@@ -1150,7 +1149,6 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
                 side: hand,
                 withHands: true,
                 facing: "Forward",
-                otherPath: "Swap",
               }
             },
             prevEnd => ({
@@ -1583,7 +1581,6 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
               side: passShoulder,
               withHands: false,
               facing: "Start",
-              otherPath: "Swap",
             },
           }], startPos);
         } else {
@@ -1611,18 +1608,16 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
 
       return handleCircleMove(({startPos}) => {
         const startingPos = { ...startPos, facing: startPos.which.facingAcross() };
-        const swappedPos = { ...startingPos, which: startingPos.which.swapAcross() };
         return combine([
           {
             beats: move.beats / 2,
-            endPosition: swappedPos,
+            endPosition: {...startingPos, which: startingPos.which.swapAcross()},
             movementPattern: {
               kind: SemanticAnimationKind.PassBy,
               side: Hand.Right,
               withHands: true,
               facing: "Start",
               around: startingPos.which.topBottomSide(),
-              otherPath: "Swap",
             },
           },
           {
@@ -1640,11 +1635,6 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
       });
 
     case "hey":
-      type HeyStep = {
-        kind: "StandStill" | "Loop" | "CenterPass" | "EndsPassIn" | "EndsPassOut",
-        endPosition: SemanticPosition,
-      }
-
       if (move.parameters.dir !== "across") {
         throw new Error("Unsupported hey direction: " + move.parameters.dir);
       }
@@ -1667,77 +1657,12 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
       const firstPassInCenter: boolean = dancerIsPair(move.parameters.who);
       const centerShoulder = firstPassInCenter === move.parameters.shoulder ? Hand.Right : Hand.Left;
       const endsShoulder = centerShoulder.opposite();
-
+      return handleMove(({ id, startPos }) => {
-      function fixupHeyOtherPath(withoutOtherPath: Map<DancerIdentity, (LowLevelMove & { heyStep?: HeyStep })[]>): Map<DancerIdentity, LowLevelMove[]> {
-        const numSteps = withoutOtherPath.get(DancerIdentity.OnesLark)!.length;
-        for (let i = 0; i < numSteps; i++) {
-          for (const id of withoutOtherPath.keys()) {
-            const lowLevelMove = withoutOtherPath.get(id)![i];
-            if (lowLevelMove.movementPattern.kind !== SemanticAnimationKind.PassBy
-              || !lowLevelMove.heyStep
-              || lowLevelMove.movementPattern.otherPath) {
-              continue;
-            }
-
-            const heyStepKind = lowLevelMove.heyStep.kind;
-            let foundPair = false;
-            for (const otherId of withoutOtherPath.keys()) {
-              const otherLowLevelMove = withoutOtherPath.get(otherId)![i];
-              if (id === otherId
-                || otherLowLevelMove.movementPattern.kind !== SemanticAnimationKind.PassBy
-                || !otherLowLevelMove.heyStep
-                || otherLowLevelMove.movementPattern.otherPath) {
-                continue;
-              }
-
-              const otherHeyStepKind = otherLowLevelMove.heyStep.kind;
-
-              if (heyStepKind === "CenterPass" && otherHeyStepKind === "CenterPass"
-                || (lowLevelMove.startPosition.which.leftRightSide() === otherLowLevelMove.startPosition.which.leftRightSide()
-                  && (heyStepKind === "EndsPassIn" && otherHeyStepKind === "EndsPassOut"
-                  || heyStepKind === "EndsPassOut" && otherHeyStepKind === "EndsPassIn"))) {
-                lowLevelMove.movementPattern.otherPath = {
-                  start: { ...otherLowLevelMove.startPosition, setOffset: lowLevelMove.startPosition.setOffset, lineOffset: lowLevelMove.startPosition.lineOffset },
-                  end: { ...otherLowLevelMove.endPosition, setOffset: lowLevelMove.endPosition.setOffset, lineOffset: lowLevelMove.endPosition.lineOffset },
-                }
-                otherLowLevelMove.movementPattern.otherPath = {
-                  start: { ...lowLevelMove.startPosition, setOffset: otherLowLevelMove.startPosition.setOffset, lineOffset: otherLowLevelMove.startPosition.lineOffset },
-                  end: { ...lowLevelMove.endPosition, setOffset: otherLowLevelMove.endPosition.setOffset, lineOffset: otherLowLevelMove.endPosition.lineOffset },
-                }
-                foundPair = true;
-                break;
-              }
-            }
-
-            if (!foundPair && heyStepKind === "EndsPassOut") {
-              // Then other is standing still.
-              const pos = {
-                ...([...withoutOtherPath.values()]
-                  .map(otherMoves => otherMoves[i])
-                  .filter(m => m.movementPattern.kind === SemanticAnimationKind.StandStill
-                    && m.endPosition.which.leftRightSide() === lowLevelMove.endPosition.which.leftRightSide())
-                [0].endPosition),
-                setOffset: lowLevelMove.startPosition.setOffset, lineOffset: lowLevelMove.startPosition.lineOffset
-              }
-              lowLevelMove.movementPattern.otherPath = { start: pos, end: pos };
-            }
-          }
-
-          for (const id of withoutOtherPath.keys()) {
-            const lowLevelMove = withoutOtherPath.get(id)![i];
-            if (lowLevelMove.movementPattern.kind === SemanticAnimationKind.PassBy
-              && !lowLevelMove.movementPattern.otherPath) {
-              throw new Error("Failed to fill in otherPath for " + id + " on hey step " + i);
-            }
-          }
-        }
-      
-        // Object was mutated.
-        return withoutOtherPath;
-      }
-
-      return fixupHeyOtherPath(handleMove(({ id, startPos }) => {
         const endsInCircle = startPos.kind === PositionKind.Circle;
+        type HeyStep = {
+          kind: "StandStill" | "Loop" | "CenterPass" | "EndsPassIn" | "EndsPassOut",
+          endPosition: SemanticPosition,
+        }
         function heyStepToPartialLowLevelMove(heyStep: HeyStep): PartialLowLevelMove & { heyStep: HeyStep } {
           return {
             beats: heyPartBeats,
@@ -1755,7 +1680,6 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
               withHands: false,
               side: heyStep.kind === "CenterPass" ? centerShoulder : endsShoulder,
               facing: "Start",
-              otherPath: undefined!, // Placeholder, fixup later.
             },
             heyStep,
           };
@@ -1895,7 +1819,7 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
           heySteps.push(nextHeyStep);
         }
         return combine(heySteps.map(heyStepToPartialLowLevelMove), { ...startingPos, hands: undefined });
-      }));
+      });
 
     case "turn alone":
       if (move.parameters.who !== "everyone" || move.beats !== 0) {

www/js/lowLevelMove.ts

@@ -99,11 +99,6 @@ export type SemanticAnimation = {
 
   around: CircleSideOrCenter,
 
-  otherPath: "Swap" | {
-    start: SemanticPosition,
-    end: SemanticPosition,
-  }
-
   side: Hand,
 
   // If true, pull by the specified hand, if false, just pass by that side without hands.
@@ -734,7 +729,9 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
           })
         ];
       case SemanticAnimationKind.PassBy:
-        const width = dancerWidth/2;
+        const passByCenter = CenterOf(move.movementPattern.around, move.startPosition.setOffset, move.startPosition.lineOffset);
+        const wide = move.movementPattern.around === "Center";
+        const width = wide ? dancerWidth : dancerWidth/2;
         const distanceAtMidpoint = move.movementPattern.side == Hand.Left ? +width : -width;
         // "Pull By" is just "Pass By" with hands.
         const passByHands = move.movementPattern.withHands
@@ -762,10 +759,7 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
               startPosition: startSetPosition,
               endPosition: { ...endSetPosition, rotation: endRotation },
               distanceAtMidpoint,
-              otherPath: move.movementPattern.otherPath === "Swap" ? undefined : {
+              center: move.movementPattern.around === "Center" ? passByCenter : undefined, // TODO Better center?
-                start: SemanticToSetPosition(move.movementPattern.otherPath.start).position,
-                end: SemanticToSetPosition(move.movementPattern.otherPath.end).position,
-              },
               hands: passByHands,
               facing: move.movementPattern.facing,
             }),

www/js/rendererConstants.ts

@@ -48,12 +48,6 @@ export function OffsetEquals(a: Offset, b: Offset): boolean {
   return a.x === b.x && a.y === b.y;
 }
 
-export function OffsetDistance(a: Offset, b: Offset): number {
-  const dx = a.x - b.x;
-  const dy = a.y - b.y;
-  return Math.sqrt(dx * dx + dy * dy);
-}
-
 export interface DancerSetPosition {
   // Position of the dancer relative to the center of their set.
   position: Offset;