Check for parallel vectors before constructing a CircumscribedCircle.

If the check fails, use a LinearBezier instead. (e.g. in map 45471).

Moved slider time and curve calculations into HitObject so that they can be reused.

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>

src/itdelatrisu/opsu/beatmap/HitObject.java

@@ -19,6 +19,11 @@
 package itdelatrisu.opsu.beatmap;
 
 import itdelatrisu.opsu.GameMod;
+import itdelatrisu.opsu.objects.curves.CatmullCurve;
+import itdelatrisu.opsu.objects.curves.CircumscribedCircle;
+import itdelatrisu.opsu.objects.curves.Curve;
+import itdelatrisu.opsu.objects.curves.LinearBezier;
+import itdelatrisu.opsu.objects.curves.Vec2f;
 
 import java.text.DecimalFormat;
 import java.text.NumberFormat;
@@ -403,6 +408,35 @@ public class HitObject {
 	 */
 	public float getPixelLength() { return pixelLength; }
 
+	/**
+	 * Returns the time duration of the slider (excluding repeats), in milliseconds.
+	 * @param sliderMultiplier the beatmap's slider movement speed multiplier
+	 * @param beatLength the beat length
+	 * @return the slider segment length
+	 */
+	public float getSliderTime(float sliderMultiplier, float beatLength) {
+		return beatLength * (pixelLength / sliderMultiplier) / 100f;
+	}
+
+	/**
+	 * Returns the slider curve.
+	 * @param scaled whether to use scaled coordinates
+	 * @return a new Curve instance
+	 */
+	public Curve getSliderCurve(boolean scaled) {
+		if (sliderType == SLIDER_PASSTHROUGH && sliderX.length == 2) {
+			Vec2f nora = new Vec2f(sliderX[0] - x, sliderY[0] - y).nor();
+			Vec2f norb = new Vec2f(sliderX[0] - sliderX[1], sliderY[0] - sliderY[1]).nor();
+			if (Math.abs(norb.x * nora.y - norb.y * nora.x) < 0.00001f)
+				return new LinearBezier(this, false, scaled);  // vectors parallel, use linear bezier instead
+			else
+				return new CircumscribedCircle(this, scaled);
+		} else if (sliderType == SLIDER_CATMULL)
+			return new CatmullCurve(this, scaled);
+		else
+			return new LinearBezier(this, sliderType == SLIDER_LINEAR, scaled);
+	}
+
 	/**
 	 * Returns the spinner end time.
 	 * @return the end time (in ms)

src/itdelatrisu/opsu/objects/Slider.java

@@ -26,10 +26,7 @@ import itdelatrisu.opsu.Options;
 import itdelatrisu.opsu.Utils;
 import itdelatrisu.opsu.beatmap.Beatmap;
 import itdelatrisu.opsu.beatmap.HitObject;
-import itdelatrisu.opsu.objects.curves.CatmullCurve;
-import itdelatrisu.opsu.objects.curves.CircumscribedCircle;
 import itdelatrisu.opsu.objects.curves.Curve;
-import itdelatrisu.opsu.objects.curves.LinearBezier;
 import itdelatrisu.opsu.states.Game;
 import itdelatrisu.opsu.ui.Colors;
 
@@ -157,7 +154,7 @@ public class Slider implements GameObject {
 		updatePosition();
 
 		// slider time calculations
-		this.sliderTime = game.getBeatLength() * (hitObject.getPixelLength() / sliderMultiplier) / 100f;
+		this.sliderTime = hitObject.getSliderTime(sliderMultiplier, game.getBeatLength());
 		this.sliderTimeTotal = sliderTime * hitObject.getRepeatCount();
 
 		// ticks
@@ -525,13 +522,7 @@ public class Slider implements GameObject {
 	public void updatePosition() {
 		this.x = hitObject.getScaledX();
 		this.y = hitObject.getScaledY();
-
+		this.curve = hitObject.getSliderCurve(true);
-		if (hitObject.getSliderType() == HitObject.SLIDER_PASSTHROUGH && hitObject.getSliderX().length == 2)
-			this.curve = new CircumscribedCircle(hitObject);
-		else if (hitObject.getSliderType() == HitObject.SLIDER_CATMULL)
-			this.curve = new CatmullCurve(hitObject);
-		else
-			this.curve = new LinearBezier(hitObject, hitObject.getSliderType() == HitObject.SLIDER_LINEAR);
 	}
 
 	@Override