Improved song resample performance

Author: RaphiMC

src/main/java/net/raphimc/noteblocklib/model/Song.java

@@ -54,12 +54,15 @@ public String getHumanReadableLength() {
     public int tickToMilliseconds(final int tick) {
         final Set<Integer> tempoEventTicks = new TreeSet<>(this.tempoEvents.getTicks());
         tempoEventTicks.add(tick);
-        tempoEventTicks.removeIf(t -> t > tick);
 
         int lastTick = 0;
         float totalMilliseconds = 0;
         for (int tempoTick : tempoEventTicks) {
-            final float tps = this.tempoEvents.get(lastTick);
+            if (tempoTick > tick) {
+                break;
+            }
+
+            final float tps = this.tempoEvents.getEffectiveTempo(lastTick);
             final int ticksInSegment = tempoTick - lastTick;
             final float segmentMilliseconds = (ticksInSegment / tps) * 1000F;
             totalMilliseconds += segmentMilliseconds;
@@ -76,13 +79,13 @@ public int millisecondsToTick(final int milliseconds) {
         int lastTick = 0;
         float totalMilliseconds = 0;
         for (int tempoTick : tempoEventTicks) {
-            final float tps = this.tempoEvents.get(lastTick);
+            final float tps = this.tempoEvents.getEffectiveTempo(lastTick);
             final int ticksInSegment = tempoTick - lastTick;
             final float segmentMilliseconds = (ticksInSegment / tps) * 1000F;
 
             if (totalMilliseconds + segmentMilliseconds >= milliseconds) {
-                float remainingMilliseconds = milliseconds - totalMilliseconds;
-                int ticksToAdd = Math.round((remainingMilliseconds / 1000F) * tps);
+                final float remainingMilliseconds = milliseconds - totalMilliseconds;
+                final int ticksToAdd = Math.round((remainingMilliseconds / 1000F) * tps);
                 return lastTick + ticksToAdd;
             }
 

src/main/java/net/raphimc/noteblocklib/model/TempoEvents.java

@@ -36,7 +36,12 @@ public float get(final int tick) {
     }
 
     public float getEffectiveTempo(final int tick) {
-        return this.tempoEvents.floorEntry(tick).getValue();
+        final Float tempo = this.tempoEvents.get(tick);
+        if (tempo != null) {
+            return tempo;
+        } else {
+            return this.tempoEvents.floorEntry(tick).getValue();
+        }
     }
 
     public void set(final int tick, final float tempo) {

src/main/java/net/raphimc/noteblocklib/util/SongResampler.java

@@ -20,10 +20,7 @@
 import net.raphimc.noteblocklib.model.Note;
 import net.raphimc.noteblocklib.model.Song;
 
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 
 public class SongResampler {
 
@@ -62,12 +59,24 @@ public static void precomputeTempoEvents(final Song song) {
         }
 
         final float newTempo = song.getTempoEvents().getTempoRange()[1]; // Highest tempo in song
-
         final Map<Integer, List<Note>> newNotes = new HashMap<>();
-        for (int tick : song.getNotes().getTicks()) {
-            final int millis = song.tickToMilliseconds(tick);
-            final int newTick = Math.round(newTempo * millis / 1000);
-            newNotes.computeIfAbsent(newTick, k -> new ArrayList<>()).addAll(song.getNotes().get(tick));
+        final Set<Integer> ticks = new TreeSet<>(song.getNotes().getTicks());
+        ticks.addAll(song.getTempoEvents().getTicks());
+
+        int lastTick = 0;
+        float totalMilliseconds = 0;
+        for (int tick : ticks) {
+            final float tps = song.getTempoEvents().getEffectiveTempo(lastTick);
+            final int ticksInSegment = tick - lastTick;
+            final float segmentMilliseconds = (ticksInSegment / tps) * 1000F;
+            totalMilliseconds += segmentMilliseconds;
+            lastTick = tick;
+
+            final List<Note> notes = song.getNotes().get(tick);
+            if (notes != null) {
+                final int newTick = Math.round(newTempo * totalMilliseconds / 1000F);
+                newNotes.computeIfAbsent(newTick, k -> new ArrayList<>()).addAll(notes);
+            }
         }
 
         song.getNotes().clear();