Correctly drew a square

src/AudioPlayer.java

@@ -5,36 +5,48 @@ import java.util.List;
 
 public class AudioPlayer extends Thread {
   public static XtFormat FORMAT;
-  private static int count = 0;
   private static volatile boolean stopped = false;
   private static List<Line> lines = new ArrayList<>();
+  private static int currentLine = 0;
+  private static float FREQUENCY = 440;
+  private static int framesDrawn = 0;
 
   static void render(XtStream stream, Object input, Object output, int frames,
                      double time, long position, boolean timeValid, long error, Object user) {
     XtFormat format = stream.getFormat();
 
-    Line line = lines.get(count % lines.size());
-
-    int neg = line.getX1() < line.getX2() || line.getY1() < line.getY2() ? 1 : -1;
-
     for (int f = 0; f < frames; f++) {
+      Line line = currentLine();
+      int framesToDraw = (int) (line.length() * 100);
+      int neg = line.getX1() < line.getX2() || line.getY1() < line.getY2() ? 1 : -1;
+
       for (int c = 0; c < format.outputs; c++) {
-        ((float[]) output)[f * format.outputs] = line.getX1() + Math.abs(line.getX2() - line.getX1()) * (float) (neg * f) / frames;
-        ((float[]) output)[f * format.outputs + 1] = line.getY1() + Math.abs(line.getY2() - line.getY1()) * (float) (neg * f) / frames;
+        ((float[]) output)[f * format.outputs] = line.getX1() + Math.abs(line.getX2() - line.getX1()) * (float) (neg * framesDrawn) / framesToDraw;
+        ((float[]) output)[f * format.outputs + 1] = line.getY1() + Math.abs(line.getY2() - line.getY1()) * (float) (neg * framesDrawn) / framesToDraw;
+      }
+
+      framesDrawn++;
+
+      if (framesDrawn > framesToDraw) {
+        framesDrawn = 0;
+        currentLine++;
       }
     }
-
-    count++;
   }
 
   public static void addLine(Line line) {
     AudioPlayer.lines.add(line);
   }
 
+  private static Line currentLine() {
+    return lines.get(currentLine % lines.size());
+  }
+
   @Override
   public void run() {
     try (XtAudio audio = new XtAudio(null, null, null, null)) {
       XtService service = XtAudio.getServiceBySetup(XtSetup.CONSUMER_AUDIO);
+
       try (XtDevice device = service.openDefaultDevice(true)) {
         if (device != null && device.supportsFormat(FORMAT)) {
 

src/Line.java

@@ -12,6 +12,10 @@ public class Line {
     this.b = new Point(x2, y2);
   }
 
+  public float length() {
+    return (float) Math.sqrt(Math.pow(getX1() - getX2(), 2) + Math.pow(getY1() - getY2(), 2));
+  }
+
   public Point getA() {
     return a;
   }