create experimental songmanagement branch

  - nicer abstraction of songs
  - split songloading from handling songs
  - cleanup singscreen

git-svn-id: svn://svn.code.sf.net/p/ultrastardx/svn/branches/experimental@2706 b956fd51-792f-4845-bead-9b4dfca2ff2c

1 files changed, 726 insertions, 0 deletions

diff --git a/songmanagement/src/base/ULyrics.pas b/songmanagement/src/base/ULyrics.pas
new file mode 100644
index 00000000..3f62db9c
--- /dev/null
+++ b/songmanagement/src/base/ULyrics.pas
@@ -0,0 +1,726 @@
+{* UltraStar Deluxe - Karaoke Game
+ *
+ * UltraStar Deluxe is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING. If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *}
+
+unit ULyrics;
+
+interface
+
+{$IFDEF FPC}
+  {$MODE Delphi}
+{$ENDIF}
+
+{$I switches.inc}
+
+uses
+  gl,
+  glext,
+  UTexture,
+  UThemes,
+  UMusic;
+
+type
+  // stores two textures for enabled/disabled states
+  TPlayerIconTex = array [0..1] of TTexture;
+
+  TLyricsEffect = (lfxSimple, lfxZoom, lfxSlide, lfxBall, lfxShift);
+  
+  PLyricWord = ^TLyricWord;
+  TLyricWord = record
+    X:          real;     // left corner
+    Width:      real;     // width
+    Start:      cardinal; // start of the word in quarters (beats)
+    Length:     cardinal; // length of the word in quarters
+    Text:       UTF8String; // text
+    Freestyle:  boolean;  // is freestyle?
+  end;
+  TLyricWordArray = array of TLyricWord;
+
+  TLyricLine = class
+    public
+      Text:           UTF8String;   // text
+      Width:          real;         // width
+      Height:         real;         // height
+      Words:          TLyricWordArray;   // words in this line
+      CurWord:        integer;      // current active word idx (only valid if line is active)
+      Start:          integer;      // start of this line in quarters (Note: negative start values are possible due to gap)
+      StartNote:      integer;      // start of the first note of this line in quarters
+      Length:         integer;      // length in quarters (from start of first to the end of the last note)
+      Players:        byte;         // players that should sing that line (bitset, Player1: 1, Player2: 2, Player3: 4)
+      LastLine:       boolean;      // is this the last line of the song?
+
+      constructor Create();
+      destructor Destroy(); override;
+      procedure Reset();
+  end;
+
+  TLyricEngine = class
+    private
+      LastDrawBeat:   real;
+      UpperLine:      TLyricLine;    // first line displayed (top)
+      LowerLine:      TLyricLine;    // second lind displayed (bottom)
+      QueueLine:      TLyricLine;    // third line (will be displayed when lower line is finished)
+
+      IndicatorTex:   TTexture;      // texture for lyric indikator
+      BallTex:        TTexture;      // texture of the ball for the lyric effect
+
+      QueueFull:      boolean;       // set to true if the queue is full and a line will be replaced with the next AddLine
+      LCounter:       integer;       // line counter
+
+      // duet mode - textures for player icons
+      // FIXME: do not use a fixed player count, use MAX_PLAYERS instead
+      PlayerIconTex:  array[0..5] of TPlayerIconTex;
+
+      // Some helper procedures for lyric drawing
+      procedure DrawLyrics (Beat: real);
+      procedure UpdateLineMetrics(LyricLine: TLyricLine);
+      procedure DrawLyricsWords(LyricLine: TLyricLine; X, Y: real; StartWord, EndWord: integer);
+      procedure DrawLyricsLine(X, W, Y, H: real; Line: TLyricLine; Beat: real);
+      procedure DrawPlayerIcon(Player: byte; Enabled: boolean; X, Y: real; Size, Alpha: real);
+      procedure DrawBall(XBall, YBall, Alpha: real);
+
+    public
+      // positions, line specific settings
+      UpperLineX:     real;       // X start-pos of UpperLine
+      UpperLineW:     real;       // Width of UpperLine with icon(s) and text
+      UpperLineY:     real;       // Y start-pos of UpperLine
+      UpperLineH:     real;       // Max. font-size of lyrics text in UpperLine
+
+      LowerLineX:     real;       // X start-pos of LowerLine
+      LowerLineW:     real;       // Width of LowerLine with icon(s) and text
+      LowerLineY:     real;       // Y start-pos of LowerLine
+      LowerLineH:     real;       // Max. font-size of lyrics text in LowerLine
+
+      // display propertys
+      LineColor_en:   TRGBA;      // Color of words in an enabled line
+      LineColor_dis:  TRGBA;      // Color of words in a disabled line
+      LineColor_act:  TRGBA;      // Color of the active word
+      FontStyle:      byte;       // Font for the lyric text
+      
+      { // currently not used
+       FadeInEffect:   byte;       // Effect for line fading in: 0: No Effect; 1: Fade Effect; 2: Move Upwards from Bottom to Pos
+       FadeOutEffect:  byte;       // Effect for line fading out: 0: No Effect; 1: Fade Effect; 2: Move Upwards
+      }
+
+      // song specific settings
+      BPM:            real;
+      Resolution:     integer;
+
+      // properties to easily read options of this class
+      property IsQueueFull: boolean read QueueFull;  // line in queue?
+      property LineCounter: integer read LCounter;   // lines that were progressed so far (after last clear)
+
+      procedure AddLine(Line: PLine);              // adds a line to the queue, if there is space
+      procedure Draw (Beat: real);                 // draw the current (active at beat) lyrics
+
+      // clears all cached song specific information
+      procedure Clear(cBPM: real = 0; cResolution: integer = 0);
+
+      function GetUpperLine(): TLyricLine;
+      function GetLowerLine(): TLyricLine;
+
+      function GetUpperLineIndex(): integer;
+
+      constructor Create(ULX, ULY, ULW, ULH, LLX, LLY, LLW, LLH: real);
+      procedure   LoadTextures;
+      destructor  Destroy; override;
+  end;
+
+implementation
+
+uses
+  SysUtils,
+  USkins,
+  TextGL,
+  UGraphic,
+  UDisplay,
+  ULog,
+  math,
+  UIni;
+
+{ TLyricLine }
+
+constructor TLyricLine.Create();
+begin
+  inherited;
+  Reset();
+end;
+
+destructor TLyricLine.Destroy();
+begin
+  SetLength(Words, 0);
+  inherited;
+end;
+
+procedure TLyricLine.Reset();
+begin
+  Start     := 0;
+  StartNote := 0;
+  Length    := 0;
+  LastLine  := False;
+
+  Text      := '';
+  Width     := 0;
+
+  // duet mode: players of that line (default: all)
+  Players   := $FF;
+
+  SetLength(Words, 0);
+  CurWord   := -1;
+end;
+
+
+{ TLyricEngine }
+
+{**
+ * Initializes the engine.
+ *}
+constructor TLyricEngine.Create(ULX, ULY, ULW, ULH, LLX, LLY, LLW, LLH: real);
+begin
+  inherited Create();
+
+  BPM := 0;
+  Resolution := 0;
+  LCounter := 0;
+  QueueFull := False;
+
+  UpperLine := TLyricLine.Create;
+  LowerLine := TLyricLine.Create;
+  QueueLine := TLyricLine.Create;
+
+  LastDrawBeat := 0;
+
+  UpperLineX := ULX;
+  UpperLineW := ULW;
+  UpperLineY := ULY;
+  UpperLineH := ULH;
+
+  LowerLineX := LLX;
+  LowerLineW := LLW;
+  LowerLineY := LLY;
+  LowerLineH := LLH;
+
+  LoadTextures;
+end;
+
+
+{**
+ * Frees memory.
+ *}
+destructor TLyricEngine.Destroy;
+begin
+  UpperLine.Free;
+  LowerLine.Free;
+  QueueLine.Free;
+  inherited;
+end;
+
+{**
+ * Clears all cached Song specific Information.
+ *}
+procedure TLyricEngine.Clear(cBPM: real; cResolution: integer);
+begin
+  BPM := cBPM;
+  Resolution := cResolution;
+  LCounter := 0;
+  QueueFull := False;
+
+  LastDrawBeat:=0;
+end;
+
+
+{**
+ * Loads textures needed for the drawing the lyrics,
+ * player icons, a ball for the ball effect and the lyric indicator.
+ *}
+procedure TLyricEngine.LoadTextures;
+var
+  I: Integer;
+begin
+  // lyric indicator (bar that indicates when the line start)
+  IndicatorTex := Texture.LoadTexture(Skin.GetTextureFileName('LyricHelpBar'), TEXTURE_TYPE_TRANSPARENT, $FF00FF);
+
+  // ball for current word hover in ball effect
+  BallTex := Texture.LoadTexture(Skin.GetTextureFileName('Ball'), TEXTURE_TYPE_TRANSPARENT, 0);
+
+  // duet mode: load player icon
+  for I := 0 to 5 do
+  begin
+    PlayerIconTex[I][0] := Texture.LoadTexture(Skin.GetTextureFileName('LyricIcon_P' + InttoStr(I+1)), TEXTURE_TYPE_TRANSPARENT, 0);
+    PlayerIconTex[I][1] := Texture.LoadTexture(Skin.GetTextureFileName('LyricIconD_P' + InttoStr(I+1)), TEXTURE_TYPE_TRANSPARENT, 0);
+  end;
+end;
+
+{**
+ * Adds LyricLine to queue.
+ * The LyricEngine stores three lines in its queue:
+ *   UpperLine: the upper line displayed in the lyrics
+ *   LowerLine: the lower line displayed in the lyrics
+ *   QueueLine: an offscreen line that precedes LowerLine
+ * If the queue is full the next call to AddLine will replace UpperLine with
+ * LowerLine, LowerLine with QueueLine and QueueLine with the Line parameter.
+ *}
+procedure TLyricEngine.AddLine(Line: PLine);
+var
+  LyricLine: TLyricLine;
+  I: integer;
+begin
+  // only add lines, if there is space
+  if not IsQueueFull then
+  begin
+    // set LyricLine to line to write to
+    if (LineCounter = 0) then
+      LyricLine := UpperLine
+    else if (LineCounter = 1) then
+      LyricLine := LowerLine
+    else
+    begin
+      // now the queue is full
+      LyricLine := QueueLine;
+      QueueFull := True;
+    end;
+  end
+  else
+  begin // rotate lines (round-robin-like)
+    LyricLine := UpperLine;
+    UpperLine := LowerLine;
+    LowerLine := QueueLine;
+    QueueLine := LyricLine;
+  end;
+
+  // reset line state
+  LyricLine.Reset();
+
+  // check if sentence has notes
+  if (Line <> nil) and (Length(Line.Note) > 0) then
+  begin
+    // copy values from SongLine to LyricLine
+    LyricLine.Start     := Line.Start;
+    LyricLine.StartNote := Line.Note[0].Start;
+    LyricLine.Length    := Line.Note[High(Line.Note)].Start +
+                           Line.Note[High(Line.Note)].Length -
+                           Line.Note[0].Start;
+    LyricLine.LastLine  := Line.LastLine;
+
+    // copy words
+    SetLength(LyricLine.Words, Length(Line.Note));
+    for I := 0 to High(Line.Note) do
+    begin
+      LyricLine.Words[I].Start     := Line.Note[I].Start;
+      LyricLine.Words[I].Length    := Line.Note[I].Length;
+      LyricLine.Words[I].Text      := Line.Note[I].Text;
+      LyricLine.Words[I].Freestyle := Line.Note[I].NoteType = ntFreestyle;
+
+      LyricLine.Text := LyricLine.Text + LyricLine.Words[I].Text;
+    end;
+
+    UpdateLineMetrics(LyricLine);
+  end;
+
+  // increase the counter
+  Inc(LCounter);
+end;
+
+{**
+ * Draws Lyrics.
+ * Draw just manages the Lyrics, drawing is done by a call of DrawLyrics.
+ * @param Beat: current Beat in Quarters
+ *}
+procedure TLyricEngine.Draw(Beat: real);
+begin
+  DrawLyrics(Beat);
+  LastDrawBeat := Beat;
+end;
+
+{**
+ * Main Drawing procedure.
+ *}
+procedure TLyricEngine.DrawLyrics(Beat: real);
+begin
+  DrawLyricsLine(UpperLineX, UpperLineW, UpperLineY, UpperLineH, UpperLine, Beat);
+  DrawLyricsLine(LowerLineX, LowerLineW, LowerLineY, LowerLineH, LowerLine, Beat);
+end;
+
+{**
+ * Draws a Player's icon.
+ *}
+procedure TLyricEngine.DrawPlayerIcon(Player: byte; Enabled: boolean; X, Y: real; Size, Alpha: real);
+var
+  IEnabled: byte;
+begin
+  if Enabled then
+    IEnabled := 0
+  else
+    IEnabled := 1;
+
+  glEnable(GL_TEXTURE_2D);
+  glEnable(GL_BLEND);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+  glBindTexture(GL_TEXTURE_2D, PlayerIconTex[Player][IEnabled].TexNum);
+
+  glColor4f(1, 1, 1, Alpha);
+  glBegin(GL_QUADS);
+    glTexCoord2f(0, 0); glVertex2f(X, Y);
+    glTexCoord2f(0, 1); glVertex2f(X, Y + Size);
+    glTexCoord2f(1, 1); glVertex2f(X + Size, Y + Size);
+    glTexCoord2f(1, 0); glVertex2f(X + Size, Y);
+  glEnd;
+
+  glDisable(GL_BLEND);
+  glDisable(GL_TEXTURE_2D);
+end;
+
+{**
+ * Draws the Ball over the LyricLine if needed.
+ *}
+procedure TLyricEngine.DrawBall(XBall, YBall, Alpha: real);
+begin
+  glEnable(GL_TEXTURE_2D);
+  glEnable(GL_BLEND);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+  glBindTexture(GL_TEXTURE_2D, BallTex.TexNum);
+
+  glColor4f(1, 1, 1, Alpha);
+  glBegin(GL_QUADS);
+    glTexCoord2f(0, 0); glVertex2f(XBall - 10, YBall);
+    glTexCoord2f(0, 1); glVertex2f(XBall - 10, YBall + 20);
+    glTexCoord2f(1, 1); glVertex2f(XBall + 10, YBall + 20);
+    glTexCoord2f(1, 0); glVertex2f(XBall + 10, YBall);
+  glEnd;
+
+  glDisable(GL_BLEND);
+  glDisable(GL_TEXTURE_2D);
+end;
+
+procedure TLyricEngine.DrawLyricsWords(LyricLine: TLyricLine;
+    X, Y: real; StartWord, EndWord: integer);
+var
+  I: integer;
+  PosX: real;
+  CurWord: PLyricWord;
+begin
+  PosX := X;
+
+  // set word positions and line size and draw the line
+  for I := StartWord to EndWord do
+  begin
+    CurWord := @LyricLine.Words[I];
+    SetFontItalic(CurWord.Freestyle);
+    SetFontPos(PosX, Y);
+    glPrint(CurWord.Text);
+    PosX := PosX + CurWord.Width;
+  end;
+end;
+
+procedure TLyricEngine.UpdateLineMetrics(LyricLine: TLyricLine);
+var
+  I: integer;
+  PosX: real;
+  CurWord: PLyricWord;
+  RequestWidth, RequestHeight: real;
+begin
+  PosX := 0;
+
+  // setup font
+  SetFontStyle(FontStyle);
+  ResetFont();
+
+  // check if line is lower or upper line and set sizes accordingly
+  // Note: at the moment upper and lower lines have same width/height
+  // and this function is just called by AddLine() but this may change
+  // so that it is called by DrawLyricsLine().
+  //if (LyricLine = LowerLine) then
+  //begin
+  //  RequestWidth  := LowerLineW;
+  //  RequestHeight := LowerLineH;
+  //end
+  //else
+  //begin
+    RequestWidth  := UpperLineW;
+    RequestHeight := UpperLineH;
+  //end;
+
+  // set font size to a reasonable value
+  LyricLine.Height := RequestHeight * 0.9;
+  SetFontSize(LyricLine.Height);
+  LyricLine.Width := glTextWidth(LyricLine.Text);
+
+  // change font-size to fit into the lyric bar
+  if (LyricLine.Width > RequestWidth) then
+  begin
+    LyricLine.Height := Trunc(LyricLine.Height * (RequestWidth / LyricLine.Width));
+    // the line is very loooong, set font to at least 1px
+    if (LyricLine.Height < 1) then
+      LyricLine.Height := 1;
+
+    SetFontSize(LyricLine.Height);
+    LyricLine.Width := glTextWidth(LyricLine.Text);
+  end;
+
+  // calc word positions and widths
+  for I := 0 to High(LyricLine.Words) do
+  begin
+    CurWord := @LyricLine.Words[I];
+
+    // - if current word is italic but not the next word get the width of the
+    // italic font to avoid overlapping.
+    // - if two italic words follow each other use the normal style's
+    // width otherwise the spacing between the words will be too big.
+    // - if it is the line's last word use normal width  
+    if CurWord.Freestyle and
+       (I+1 < Length(LyricLine.Words)) and
+       (not LyricLine.Words[I+1].Freestyle) then
+    begin
+      SetFontItalic(true);
+    end;
+
+    CurWord.X := PosX;
+    CurWord.Width := glTextWidth(CurWord.Text);
+    PosX := PosX + CurWord.Width;
+    SetFontItalic(false);
+  end;
+end;
+
+
+{**
+ * Draws one LyricLine
+ *}
+procedure TLyricEngine.DrawLyricsLine(X, W, Y, H: real; Line: TLyricLine; Beat: real);
+var
+  CurWord:        PLyricWord;     // current word
+  LastWord:       PLyricWord;     // last word in line
+  NextWord:       PLyricWord;     // word following current word
+  Progress:       real;           // progress of singing the current word
+  LyricX, LyricY: real;           // left/top lyric position
+  WordY: real;                    // word y-position
+  LyricsEffect: TLyricsEffect;
+  Alpha: real;                    // alphalevel to fade out at end
+  ClipPlaneEq: array[0..3] of GLdouble; // clipping plane for slide effect 
+  {// duet mode
+  IconSize: real;                 // size of player icons
+  IconAlpha: real;                // alpha level of player icons
+  }
+begin
+  // do not draw empty lines
+  if (Length(Line.Words) = 0) then
+    Exit;
+
+  {
+  // duet mode
+  IconSize := (2 * Height);
+  IconAlpha := Frac(Beat/(Resolution*4));
+
+  DrawPlayerIcon (0, True, X, Y + (42 - IconSize) / 2 , IconSize, IconAlpha);
+  DrawPlayerIcon (1, True, X + IconSize + 1,  Y + (42 - IconSize) / 2, IconSize, IconAlpha);
+  DrawPlayerIcon (2, True, X + (IconSize + 1)*2, Y + (42 - IconSize) / 2, IconSize, IconAlpha);
+  }
+
+  // set font size and style
+  SetFontStyle(FontStyle);
+  ResetFont();
+  SetFontSize(Line.Height);
+
+  // center lyrics
+  LyricX := X + (W - Line.Width) / 2;
+  LyricY := Y + (H - Line.Height) / 2;
+  // get lyrics effect
+  LyricsEffect := TLyricsEffect(Ini.LyricsEffect);
+
+  // TODO: what about alpha in freetype outline fonts?
+  Alpha := 1;
+
+  // check if this line is active (at least its first note must be active)
+  if (Beat >= Line.StartNote) then
+  begin
+    // if this line just got active, CurWord is -1,
+    // this means we should try to make the first word active
+    if (Line.CurWord = -1) then
+      Line.CurWord := 0;
+
+    // check if the current active word is still active.
+    // Otherwise proceed to the next word if there is one in this line.
+    // Note: the max. value of Line.CurWord is High(Line.Words)
+    if (Line.CurWord < High(Line.Words)) and
+       (Beat >= Line.Words[Line.CurWord + 1].Start) then
+    begin
+      Inc(Line.CurWord);
+    end;
+
+    // determine current and last word in this line.
+    // If the end of the line is reached use the last word as current word.
+    LastWord := @Line.Words[High(Line.Words)];
+    CurWord := @Line.Words[Line.CurWord];
+    if (Line.CurWord+1 < Length(Line.Words)) then
+      NextWord := @Line.Words[Line.CurWord+1]
+    else
+      NextWord := nil;
+
+    // calc the progress of the lyrics effect
+    Progress := (Beat - CurWord.Start) / CurWord.Length;
+    if (Progress >= 1) then
+      Progress := 1;
+    if (Progress <= 0) then
+      Progress := 0;
+
+    // last word of this line finished, but this line did not hide -> fade out
+    if Line.LastLine and
+       (Beat > LastWord.Start + LastWord.Length) then
+    begin
+      Alpha := 1 - (Beat - (LastWord.Start + LastWord.Length)) / 15;
+      if (Alpha < 0) then
+        Alpha := 0;
+    end;
+
+    // draw sentence before current word
+    if (LyricsEffect in [lfxSimple, lfxBall, lfxShift]) then
+      // only highlight current word and not that ones before in this line
+      glColorRGB(LineColor_en, Alpha)
+    else
+      glColorRGB(LineColor_act, Alpha);
+    DrawLyricsWords(Line, LyricX, LyricY, 0, Line.CurWord-1);
+
+    // draw rest of sentence (without current word)
+    glColorRGB(LineColor_en, Alpha);
+    if (NextWord <> nil) then
+    begin
+      DrawLyricsWords(Line, LyricX + NextWord.X, LyricY,
+                      Line.CurWord+1, High(Line.Words));
+    end;
+
+    // draw current word
+    if (LyricsEffect in [lfxSimple, lfxBall, lfxShift]) then
+    begin
+      if (LyricsEffect = lfxShift) then
+        WordY := LyricY - 8 * (1-Progress)
+      else
+        WordY := LyricY;
+
+      // change the color of the current word
+      glColor4f(LineColor_act.r, LineColor_act.g, LineColor_act.b, Alpha);
+      DrawLyricsWords(Line, LyricX + CurWord.X, WordY, Line.CurWord, Line.CurWord);
+    end
+    // change color and zoom current word
+    else if (LyricsEffect = lfxZoom) then
+    begin
+      glPushMatrix;
+
+      // zoom at word center
+      glTranslatef(LyricX + CurWord.X + CurWord.Width/2,
+                   LyricY + Line.Height/2, 0);
+      glScalef(1.0 + (1-Progress) * 0.5, 1.0 + (1-Progress) * 0.5, 1.0);
+
+      glColor4f(LineColor_act.r, LineColor_act.g, LineColor_act.b, Alpha);
+      DrawLyricsWords(Line, -CurWord.Width/2, -Line.Height/2, Line.CurWord, Line.CurWord);
+
+      glPopMatrix;
+    end
+    // split current word into active and non-active part
+    else if (LyricsEffect = lfxSlide) then
+    begin
+      // enable clipping and set clip equation coefficients to zeros
+      glEnable(GL_CLIP_PLANE0);
+      FillChar(ClipPlaneEq[0], SizeOf(ClipPlaneEq), 0);
+
+      glPushMatrix;
+      glTranslatef(LyricX + CurWord.X, LyricY, 0);
+
+      // clip non-active right part of the current word
+      ClipPlaneEq[0] := -1;
+      ClipPlaneEq[3] := CurWord.Width * Progress;
+      glClipPlane(GL_CLIP_PLANE0, @ClipPlaneEq);
+      // and draw active left part
+      glColor4f(LineColor_act.r, LineColor_act.g, LineColor_act.b, Alpha);
+      DrawLyricsWords(Line, 0, 0, Line.CurWord, Line.CurWord);
+
+      // clip active left part of the current word
+      ClipPlaneEq[0] := -ClipPlaneEq[0];
+      ClipPlaneEq[3] := -ClipPlaneEq[3];
+      glClipPlane(GL_CLIP_PLANE0, @ClipPlaneEq);
+      // and draw non-active right part
+      glColor4f(LineColor_en.r, LineColor_en.g, LineColor_en.b, Alpha);
+      DrawLyricsWords(Line, 0, 0, Line.CurWord, Line.CurWord);
+
+      glPopMatrix;
+
+      glDisable(GL_CLIP_PLANE0);
+    end;
+
+    // draw the ball onto the current word
+    if (LyricsEffect = lfxBall) then
+    begin
+      DrawBall(LyricX + CurWord.X + CurWord.Width * Progress,
+               LyricY - 15 - 15*sin(Progress * Pi), Alpha);
+    end;
+  end
+  else
+  begin
+    // this section is called if the whole line can be drawn at once and no
+    // word is highlighted.
+
+    // enable the upper, disable the lower line
+    if (Line = UpperLine) then
+      glColorRGB(LineColor_en)
+    else
+      glColorRGB(LineColor_dis);
+
+    DrawLyricsWords(Line, LyricX, LyricY, 0, High(Line.Words));
+  end;
+end;
+
+{**
+ * @returns a reference to the upper line
+ *}
+function TLyricEngine.GetUpperLine(): TLyricLine;
+begin
+  Result := UpperLine;
+end;
+
+{**
+ * @returns a reference to the lower line
+ *}
+function TLyricEngine.GetLowerLine(): TLyricLine;
+begin
+  Result := LowerLine;
+end;
+
+{**
+ * @returns the index of the upper line
+ *}
+function TLyricEngine.GetUpperLineIndex(): integer;
+const
+  QUEUE_SIZE = 3;
+begin
+  // no line in queue
+  if (LineCounter <= 0) then
+    Result := -1
+  // no line has been removed from queue yet
+  else if (LineCounter <= QUEUE_SIZE) then
+    Result := 0
+  // lines have been removed from queue already
+  else
+    Result := LineCounter - QUEUE_SIZE;
+end;
+
+end.
+