Add debug display option to renderer/animations.

www/js/animation.ts

@@ -43,12 +43,15 @@ export abstract class AnimationSegment {
     return interpolateLinear(progress, this.startPosition.rotation, this.endPosition.rotation);
   }
 
+  abstract drawDebug(ctx: CanvasRenderingContext2D, progress: number);
+
   positionAtFraction(progress: number) : DancerSetPosition {
     return {
       position: this.interpolateOffset(progress),
       rotation: this.interpolateRotation(progress),
       leftArmEnd: this.interpolateHandOffset(progress, Hand.Left),
       rightArmEnd: this.interpolateHandOffset(progress, Hand.Right),
+      drawDebug: (ctx) => this.drawDebug(ctx, progress),
     }
   }
 }
@@ -84,6 +87,13 @@ export class LinearAnimationSegment extends AnimationSegment {
   override interpolateOffset(progress: number): Offset {
     return interpolateLinearOffset(progress, this.startPosition.position, this.endPosition.position);
   }
+
+  override drawDebug(ctx: CanvasRenderingContext2D, progress: number) {
+    ctx.beginPath();
+    ctx.moveTo(this.startPosition.position.x, this.startPosition.position.y);
+    ctx.lineTo(this.endPosition.position.x, this.endPosition.position.y);
+    ctx.stroke();
+  }
 }
 
 export interface AnimationTransitionFlags {
@@ -206,6 +216,11 @@ export class TransitionAnimationSegment extends AnimationSegment {
 
     return actualHandOffset;
   }
+
+  override drawDebug(ctx: CanvasRenderingContext2D, progress: number) {
+    // TODO display transition somehow?
+    this.actualAnimation.drawDebug(ctx, progress);
+  }
 }
 
 // TODO Not sure this really belongs here instead of on some Semantic* type.
@@ -359,6 +374,25 @@ export class RotationAnimationSegment extends AnimationSegment {
         return hand === Hand.Left ? leftShoulder : rightShoulder;
     }
   }
+
+  override drawDebug(ctx: CanvasRenderingContext2D, progress: number) {
+    ctx.beginPath();
+    const distance = this.closer?.middleDistance ?? this.endDistance;
+    let start: number, end: number;
+    if (Math.abs(this.endRotation - this.startRotation) >= 360) {
+      start = 0;
+      end = 2 * Math.PI;
+    } else {
+      start = degreesToRadians(this.startRotation);
+      end = degreesToRadians(this.endRotation);
+    }
+    ctx.ellipse(this.center.x, this.center.y,
+                this.xRadius * distance, this.yRadius * distance,
+                0,
+                start, end,
+                this.endRotation < this.startRotation);
+    ctx.stroke();
+  }
 }
 
 // For "PassBy" and related moves where stepping straight forward would walk into the
@@ -372,6 +406,7 @@ export class StepWideLinearAnimationSegment extends AnimationSegment {
   private readonly actualCenter: Offset;
   private readonly hands: Map<Hand, HandAnimation>;
   private readonly facing: "Start" | "Forward";
+  private readonly midPoint: Offset;
 
   constructor({ beats, startPosition, endPosition, distanceAtMidpoint, otherPath, hands, facing }: {
     beats: number;
@@ -450,6 +485,8 @@ t = -b/2a
     }
 
     this.handTransitionProgress = 0.5 / beats;
+
+    this.midPoint = this.interpolateOffset(this.progressCenter ?? 0.5);
   }
 
   interpolateOffset(progress: number): Offset {
@@ -512,6 +549,14 @@ t = -b/2a
         return hand.shoulderPosition();
     }
   }
+
+  override drawDebug(ctx: CanvasRenderingContext2D, progress: number) {
+    ctx.beginPath();
+    ctx.moveTo(this.startPosition.position.x, this.startPosition.position.y);
+    ctx.lineTo(this.midPoint.x, this.midPoint.y);
+    ctx.lineTo(this.endPosition.position.x, this.endPosition.position.y);
+    ctx.stroke();
+  }
 }
 
 export class SlideAnimationSegment extends AnimationSegment {
@@ -558,6 +603,15 @@ export class SlideAnimationSegment extends AnimationSegment {
     const { segment, segmentProgress } = this.selectSegment(progress);
     return segment.interpolateRotation(segmentProgress);
   }
+
+  override drawDebug(ctx: CanvasRenderingContext2D, progress: number) {
+    // TODO Right way to handle the slide part?
+    const slide = OffsetTimes(this.slideAmount, progress);
+    ctx.translate(slide.x, slide.y);
+
+    const { segment, segmentProgress } = this.selectSegment(progress);
+    segment.drawDebug(ctx, segmentProgress);
+  }
 }
 
 export class Animation {
@@ -633,13 +687,17 @@ export class Animation {
     for (const [id, animationSegments] of this.segments.entries()) {
       const basePosition = positionAtBeat(animationSegments, beat);
       if (progression !== 0) {
+        const progressionOffset = OffsetTimes(
+          this.progression,
+          progression * (id.coupleRole === CoupleRole.Ones ? 1 : -1));
         res.set(id, {
           ...basePosition,
           position: OffsetPlus(
             basePosition.position,
-            OffsetTimes(
-              this.progression,
-              progression * (id.coupleRole === CoupleRole.Ones ? 1 : -1)))
+            progressionOffset),
+          drawDebug: basePosition.drawDebug ?
+            (ctx) => { ctx.translate(progressionOffset.x, progressionOffset.y); basePosition.drawDebug!(ctx); }
+            : undefined
         });
       } else {
         res.set(id, basePosition);

www/js/interpreter.ts

@@ -1157,7 +1157,7 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
               beats: turnBeats,
               endPosition: {
                 kind: PositionKind.Circle,
-                which: endWhich.swapUpAndDown(),
+                which: endWhich,
                 facing: endWhich.facingAcross(),
                 hands: prevEnd.hands,
                 setOffset: prevEnd.setOffset,
@@ -1183,7 +1183,7 @@ function moveAsLowLevelMoves({ move, nextMove, startingPos, numProgessions }: {
               endPosition: {
                 ...startingPos,
                 // TODO Does CourtesyTurn always end in same position?
-                which: startPos.which.swapUpAndDown(),
+                which: startPos.which,
                 facing: startPos.which.facingAcross(),
               },
               movementPattern: {

www/js/main.ts

@@ -89,6 +89,13 @@ function updateCanvasSettings(arg : ResetCanvasSetting) {
 
 updateCanvasSettings({});
 
+const debugRender = document.createElement('input');
+debugRender.type = 'checkbox';
+debugRender.checked = r.drawDebug;
+const debugRenderLabel = document.createElement('label');
+debugRenderLabel.htmlFor = debugRender.id = 'debugRender';
+debugRenderLabel.innerText = 'Debug display';
+
 const bpmSelector = document.createElement('input');
 bpmSelector.type = 'number';
 bpmSelector.value = '180';
@@ -147,6 +154,12 @@ function drawAtCurrentBeat() {
     .classList.add('currentMove');
 }
 
+debugRender.addEventListener('change', (ev) => {
+  r.drawDebug = debugRender.checked;
+  drawAtCurrentBeat();
+  restartAnimation(false);
+})
+
 beatSlider.addEventListener('input', (ev) => {
   drawAtCurrentBeat();
   beatDisplay.innerText = beatSlider.valueAsNumber.toFixed(1);
@@ -400,6 +413,10 @@ displaySettingsDiv.appendChild(document.createElement('br'));
 displaySettingsDiv.appendChild(extraLinesLabel);
 displaySettingsDiv.appendChild(extraLinesSelector);
 
+displaySettingsDiv.appendChild(document.createElement('br'));
+displaySettingsDiv.appendChild(debugRender);
+displaySettingsDiv.appendChild(debugRenderLabel);
+
 wrapperDiv.appendChild(displaySettingsDiv);
 
 // Default dance is Two Hearts in Time by Isaac Banner. Selected arbitrarily.

www/js/renderer.ts

@@ -44,6 +44,7 @@ export class Renderer {
   animation?: Animation;
   extraSets?: number;
   extraLines?: number;
+  drawDebug: boolean = false;
 
   constructor(canvas: HTMLCanvasElement, ctx: CanvasRenderingContext2D) {
     this.canvas = canvas;
@@ -83,7 +84,7 @@ export class Renderer {
     this.ctx.fillStyle = backupFillStyle;
   }
 
-  drawDancer(position: DancerSetPosition, identity: ExtendedDancerIdentity, offsetSets: number) {
+  drawDancer(position: DancerSetPosition, identity: ExtendedDancerIdentity, offsetSets: number, drawDebug: boolean) {
     this.ctx.save();
 
     this.ctx.translate(identity.relativeLine * lineDistance,
@@ -94,6 +95,14 @@ export class Renderer {
     };
     this.ctx.fillStyle = this.ctx.strokeStyle = colorForDancer(realIdentity);
 
+    if (drawDebug) {
+      if (this.drawDebug && position.drawDebug) {
+        this.ctx.save();
+        this.ctx.lineWidth = 0.05;
+        position.drawDebug(this.ctx);
+        this.ctx.restore();
+      }
+    } else {
       this.ctx.translate(position.position.x, position.position.y);
       this.ctx.rotate(-degreesToRadians(position.rotation));
 
@@ -113,22 +122,23 @@ export class Renderer {
         this.ctx.lineTo(position.rightArmEnd.x, position.rightArmEnd.y);
         this.ctx.stroke();
       }
+    }
 
     this.ctx.restore();
   }
 
-  drawSet(positions: DancersSetPositions, relativeSet: number, relativeLine: number, offsetSets: number) {
+  drawSet(positions: DancersSetPositions, relativeSet: number, relativeLine: number, offsetSets: number, drawDebug: boolean) {
     for (const entry of positions.entries()) {
-      this.drawDancer(entry[1], { setIdentity: entry[0], relativeLine, relativeSet }, offsetSets);
+      this.drawDancer(entry[1], { setIdentity: entry[0], relativeLine, relativeSet }, offsetSets, drawDebug);
     }
   }
 
-  drawSets(positions: DancersSetPositions, offsetSets?: number) {
+  drawSets(positions: DancersSetPositions, offsetSets?: number, drawDebug?: boolean) {
     const extraSets = this.extraSets ?? 0;
     const extraLines = this.extraLines ?? 0;
     for (var relativeLine = -extraLines; relativeLine <= extraLines; relativeLine++) {
       for (var relativeSet = -extraSets; relativeSet <= extraSets; relativeSet++) {
-        this.drawSet(positions, relativeSet, relativeLine, offsetSets ?? 0);
+        this.drawSet(positions, relativeSet, relativeLine, offsetSets ?? 0, !!drawDebug);
       }
     }
   }
@@ -153,7 +163,9 @@ export class Renderer {
     for (var i = increments; i >= 0; i--) {
       const beatToDraw = beat - i*incrementLength;
       this.ctx.globalAlpha = i == 0 ? 1 : (1 - i/increments)*0.3;
-      this.drawSets(this.animation.positionsAtBeat(beatToDraw, progression % 2), offsetSets);
+      const positions = this.animation.positionsAtBeat(beatToDraw, progression % 2);
+      if (this.drawDebug) this.drawSets(positions, offsetSets, true);
+      this.drawSets(positions, offsetSets, false);
     }
   }
 

www/js/rendererConstants.ts

@@ -63,6 +63,7 @@ export interface DancerSetPosition {
   rotation: number;
   leftArmEnd?: Offset;
   rightArmEnd?: Offset;
+  drawDebug?: (CanvasRenderingContext2D) => void;
 }
 
 export type DancersSetPositions = Map<DancerIdentity, DancerSetPosition>;