Render wideband spectrum with OpenGL primitives

WidebandView.pas

@@ -30,6 +30,7 @@ type
     FPoints: array of TPoint;
     FGLTex: GLuint;
     FDirty: Boolean;
+    FGLBackgroundDirty: Boolean;
     FSampleRateHz: Double;
     FRefLevel: Double;
     FRange: Double;
@@ -51,10 +52,14 @@ type
     function ComputeSpectrumWDSP(const Samples: array of SmallInt;
       Count: Integer): Boolean;
     procedure CloseWDSPAnalyzer;
-    procedure DrawCPU(W, H: Integer);
+    function BuildSpectrumPoints(PlotW, H: Integer): Boolean;
+    procedure DrawCPU(W, H: Integer; IncludeSpectrum: Boolean = True);
     procedure PaintCPU(C: TCanvas);
     procedure PaintGL(C: TOpenGLControl);
     procedure ColorToGL(AColor: TColor; out R, G, B: GLFloat);
+    procedure DrawSpectrumGL(PlotW, H: Integer);
+    procedure DrawHamBandGL(PlotW, H: Integer; F1, F2: Double; AColor: TColor);
+    procedure DrawHamBandsGL(PlotW, H: Integer);
     function SourceFreqToBin(FreqHz: Double; BinCount: Integer): Integer;
     function FreqToX(FreqHz: Double; W: Integer): Integer;
     function GridStepHz(W: Integer): Double;
@@ -123,6 +128,7 @@ begin
   SetLength(FWDSPPixels, WB_WDSP_PIXELS);
   FGLTex := 0;
   FDirty := True;
+  FGLBackgroundDirty := True;
 end;
 
 destructor TWidebandView.Destroy;
@@ -139,6 +145,7 @@ procedure TWidebandView.SetTheme(const T: TAppTheme);
 begin
   FTheme := T;
   FDirty := True;
+  FGLBackgroundDirty := True;
 end;
 
 procedure TWidebandView.SetSampleRateHz(AHz: Double);
@@ -180,6 +187,7 @@ begin
   FSourceStartHz := SourceStartHz;
   FSourceEndHz := SourceEndHz;
   FDirty := True;
+  FGLBackgroundDirty := True;
   Result := True;
 end;
 
@@ -218,7 +226,10 @@ begin
   W := Max(1, W);
   H := Max(1, H);
   if (FBitmap.Width <> W) or (FBitmap.Height <> H) then
+  begin
     FBitmap.SetSize(W, H);
+    FGLBackgroundDirty := True;
+  end;
 end;
 
 procedure TWidebandView.SetBitmapSize(W, H: Integer);
@@ -560,11 +571,42 @@ begin
   end;
 end;
 
-procedure TWidebandView.DrawCPU(W, H: Integer);
+function TWidebandView.BuildSpectrumPoints(PlotW, H: Integer): Boolean;
+var
+  X, Y, Bin, N, TopH: Integer;
+  DB, InvRange, SrcHz, Nyq: Double;
+begin
+  Result := False;
+  N := Length(FData);
+  if (N <= 1) or (PlotW <= 0) or (H <= 0) then Exit;
+  TopH := Max(1, H - 1);
+  InvRange := 1.0 / Max(1.0, FRange);
+  SetLength(FPoints, PlotW);
+  Nyq := FSampleRateHz * 0.5;
+  if Nyq <= 0.0 then Nyq := 61440000.0;
+  for X := 0 to PlotW - 1 do
+  begin
+    SrcHz := FSourceStartHz +
+      X / Max(1, PlotW - 1) * (FSourceEndHz - FSourceStartHz);
+    if (SrcHz < 0.0) or (SrcHz > Nyq) then
+      DB := -200.0
+    else
+    begin
+      Bin := SourceFreqToBin(SrcHz, N);
+      DB := FData[Bin];
+    end;
+    Y := Round((FRefLevel - DB) * InvRange * TopH);
+    Y := EnsureRange(Y, 1, TopH);
+    FPoints[X] := Point(X, Y);
+  end;
+  Result := True;
+end;
+
+procedure TWidebandView.DrawCPU(W, H: Integer; IncludeSpectrum: Boolean);
 var
   C: TCanvas;
-  X, Y, Bin, N, TopH, PlotW, ScaleX: Integer;
+  X, Y, TopH, PlotW, ScaleX: Integer;
-  DB, DBMin, InvRange, StepHz, FreqHz, SrcHz, Nyq: Double;
+  DB, DBMin, InvRange, StepHz, FreqHz: Double;
 begin
   EnsureBitmap(W, H);
   C := FBitmap.Canvas;
@@ -614,27 +656,8 @@ begin
     DB := DB - 20.0;
   end;
 
-  N := Length(FData);
+  if IncludeSpectrum and BuildSpectrumPoints(PlotW, H) then
-  if N > 1 then
   begin
-    SetLength(FPoints, PlotW);
-    Nyq := FSampleRateHz * 0.5;
-    if Nyq <= 0.0 then Nyq := 61440000.0;
-    for X := 0 to PlotW - 1 do
-    begin
-      SrcHz := FSourceStartHz +
-        X / Max(1, PlotW - 1) * (FSourceEndHz - FSourceStartHz);
-      if (SrcHz < 0.0) or (SrcHz > Nyq) then
-        DB := -200.0
-      else
-      begin
-        Bin := SourceFreqToBin(SrcHz, N);
-        DB := FData[Bin];
-      end;
-      Y := Round((FRefLevel - DB) * InvRange * TopH);
-      Y := EnsureRange(Y, 1, TopH);
-      FPoints[X] := Point(X, Y);
-    end;
     if FFillSpectrum then
       DrawSpectrumGradient(FPoints, PlotW, H);
     C.Pen.Color := TColor($0040FF80);
@@ -645,7 +668,10 @@ begin
 
   C.Font.Color := FTheme.Text;
   C.TextOut(6, 4, 'Wideband');
-  FDirty := False;
+  if IncludeSpectrum then
+    FDirty := False
+  else
+    FGLBackgroundDirty := False;
 end;
 
 procedure TWidebandView.DrawRuler;
@@ -716,6 +742,90 @@ begin
   B := ((AColor shr 16) and $FF) / 255.0;
 end;
 
+procedure TWidebandView.DrawSpectrumGL(PlotW, H: Integer);
+var
+  I: Integer;
+  R, G, B: GLFloat;
+  ATop, ABot: GLFloat;
+begin
+  if not BuildSpectrumPoints(PlotW, H) then Exit;
+  glEnable(GL_BLEND);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+  if FFillSpectrum then
+  begin
+    R := FTheme.SpecGradR / 255.0;
+    G := FTheme.SpecGradG / 255.0;
+    B := FTheme.SpecGradB / 255.0;
+    glBegin(GL_TRIANGLE_STRIP);
+    for I := 0 to PlotW - 1 do
+    begin
+      ATop := 0.44;
+      ABot := 0.02;
+      glColor4f(R, G, B, ATop);
+      glVertex2f(FPoints[I].X, H - FPoints[I].Y);
+      glColor4f(R, G, B, ABot);
+      glVertex2f(FPoints[I].X, 0);
+    end;
+    glEnd;
+  end;
+
+  glColor4f(0.25, 1.0, 0.50, 1.0);
+  glBegin(GL_LINE_STRIP);
+  for I := 0 to PlotW - 1 do
+    glVertex2f(FPoints[I].X, H - FPoints[I].Y);
+  glEnd;
+
+  glDisable(GL_BLEND);
+end;
+
+procedure TWidebandView.DrawHamBandGL(PlotW, H: Integer; F1, F2: Double;
+  AColor: TColor);
+var
+  X1, X2: Integer;
+  R, G, B: GLFloat;
+begin
+  X1 := FreqToX(F1, PlotW);
+  X2 := FreqToX(F2, PlotW);
+  if (X2 <= 0) or (X1 >= PlotW) then Exit;
+  X1 := EnsureRange(X1, 0, PlotW - 1);
+  X2 := EnsureRange(X2, 0, PlotW - 1);
+  if X2 <= X1 then Exit;
+  ColorToGL(AColor, R, G, B);
+  glEnable(GL_BLEND);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+  glColor4f(R, G, B, 0.34);
+  glBegin(GL_QUADS);
+    glVertex2f(X1, 0);
+    glVertex2f(X2 + 1, 0);
+    glVertex2f(X2 + 1, H);
+    glVertex2f(X1, H);
+  glEnd;
+  glColor4f(R, G, B, 0.46);
+  glBegin(GL_QUADS);
+    glVertex2f(X1, H - Min(H, 15));
+    glVertex2f(X2 + 1, H - Min(H, 15));
+    glVertex2f(X2 + 1, H);
+    glVertex2f(X1, H);
+  glEnd;
+  glDisable(GL_BLEND);
+end;
+
+procedure TWidebandView.DrawHamBandsGL(PlotW, H: Integer);
+begin
+  DrawHamBandGL(PlotW, H, 1810000, 2000000, TColor($003B8F5A));
+  DrawHamBandGL(PlotW, H, 3500000, 3800000, TColor($004D8F3B));
+  DrawHamBandGL(PlotW, H, 5258500, 5403500, TColor($00688F3B));
+  DrawHamBandGL(PlotW, H, 7000000, 7300000, TColor($00808D34));
+  DrawHamBandGL(PlotW, H, 10100000, 10150000, TColor($008F7834));
+  DrawHamBandGL(PlotW, H, 14000000, 14350000, TColor($008F5D34));
+  DrawHamBandGL(PlotW, H, 18068000, 18168000, TColor($008F4934));
+  DrawHamBandGL(PlotW, H, 21000000, 21450000, TColor($008C3E58));
+  DrawHamBandGL(PlotW, H, 24890000, 24990000, TColor($007A3E8C));
+  DrawHamBandGL(PlotW, H, 28000000, 29700000, TColor($005B4B9A));
+  DrawHamBandGL(PlotW, H, 50000000, 51990000, TColor($003C729A));
+end;
+
 procedure TWidebandView.UploadBitmapToGL;
 var
   X, Y, I: Integer;
@@ -767,9 +877,9 @@ begin
     SetBitmapSize(W, H);
     NeedUpload := True;
   end;
-  if FDirty then
+  if FGLBackgroundDirty then
   begin
-    DrawCPU(W, H);
+    DrawCPU(W, H, False);
     NeedUpload := True;
   end;
   if FGLTex = 0 then
@@ -797,9 +907,13 @@ begin
   glBindTexture(GL_TEXTURE_2D, 0);
   glDisable(GL_TEXTURE_2D);
 
+  PlotW := Max(1, W - WB_DB_SCALE_W);
+  DrawSpectrumGL(PlotW, H);
+  DrawHamBandsGL(PlotW, H);
+  FDirty := False;
+
   if (FMarkerHz >= FViewStartHz) and (FMarkerHz <= FViewEndHz) then
   begin
-    PlotW := Max(1, W - WB_DB_SCALE_W);
     X := EnsureRange(FreqToX(FMarkerHz, PlotW), 0, PlotW - 1);
     glEnable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);