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{
Copyright 2003-2017 Michalis Kamburelis.
This file is part of "Castle Game Engine".
"Castle Game Engine" is free software; see the file COPYING.txt,
included in this distribution, for details about the copyright.
"Castle Game Engine" 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.
----------------------------------------------------------------------------
}
{ This is a simple demo of the recursive space filling curves implemented in the
CastleSpaceFillingCurves unit.
Always run with at least 2 command-line params:
curve-type (may be "peano" or "hilbert" for now)
curve-level (
for peano, reasonable example values are between 1 and 6;
for hilbert, reasonable example values are between 1 and 9;
be careful with larger levels --- the curve size grows
exponentially fast, as the levels are actually just the recursion depth)
For example
./draw_space_filling_curve peano 4
./draw_space_filling_curve hilbert 4
Set StepsToRedisplay variable (lower in this file) always to 1
to get more progressive display (you will see while drawing
in what order the curve is drawn, although the whole drawing
will be slower).
}
program draw_space_filling_curve;
{$ifdef MSWINDOWS} {$apptype GUI} {$endif}
uses SysUtils, CastleWindow, CastleUtils, CastleGLUtils, CastleParameters,
CastleImages, CastleVectors, Math, CastleSpaceFillingCurves, CastleStringUtils, CastleGLImages,
CastleKeysMouse, CastleColors;
var
Window: TCastleWindowCustom;
CurveImage: TRGBImage;
const
CurveCol: TVector3Byte = (Data: (255, 255, 255));
CurveImageBGCol: TVector4Byte = (Data: (0, 0, 0, 0));
{ CastleWindow callbacks ------------------------------------------------------- }
procedure Render(Container: TUIContainer);
var
GLImage: TGLImage;
begin
{ If DoubleBuffer available, then use it.
This program should work perfectly with and without DoubleBuffer. }
if Window.DoubleBuffer then RenderContext.Clear([cbColor], Gray);
GLImage := TGLImage.Create(CurveImage, false);
try
GLImage.Draw(0, 0);
finally FreeAndNil(GLImage) end;
end;
procedure CloseQueryNotAllowed(Container: TUIContainer); begin end;
{ curve generation ------------------------------------------------------------ }
var
LastX: Integer = 1;
LastY: Integer = 1;
StepNum: Int64 = 0;
{ initialized in main program }
StepXSize, StepYSize, StepsToRedisplay: Integer;
procedure Step(Angle: TSFCAngle; StepFuncData: Pointer);
var
x, y: Integer;
begin
x := LastX;
y := LastY;
case Angle of
0: x+=StepXSize;
1: y+=StepYSize;
2: x-=StepXSize;
else {3:} y-=StepYSize;
end;
if Between(x, 0, Integer(CurveImage.Width)-1) and
Between(y, 0, Integer(CurveImage.Height)-1) and
Between(LastX, 0, Integer(CurveImage.Width-1)) and
Between(LastY, 0, Integer(CurveImage.Height-1)) then
begin
if x = LastX then
CurveImage.VerticalLine(x, Min(y, LastY), Max(y, LastY), CurveCol)
else
CurveImage.HorizontalLine(Min(x, LastX), Max(x, LastX), y, CurveCol);
end;
LastX := x;
LastY := y;
Inc(StepNum);
if StepNum mod StepsToRedisplay = 0 then
begin
Window.Invalidate;
Application.ProcessAllMessages;
{ Since we use TCastleWindowDemo, user is able to close the window by
pressing Escape. In this case we want to break the curve generation
and end the program. }
if Window.Closed then
Halt;
end;
end;
var
{ vars that may be taken from params }
DoPeano: boolean = true;
Level: Cardinal = 4;
InitialAngle: TSFCAngle = 0;
InitialOrient: boolean; { default value depends on DoPeano }
StepsResolution, AllStepsCount: Cardinal;
begin
Window := TCastleWindowCustom.Create(Application);
{ parse params }
if Parameters.High >= 1 then
case ArrayPosStr(Parameters[1], ['peano', 'hilbert']) of
0: DoPeano := true;
1: DoPeano := false;
else raise EInvalidParams.Create('First param must be "peano" or "hilbert"');
end;
if Parameters.High >= 2 then
Level := StrToInt(Parameters[2]);
if Parameters.High >= 3 then
InitialAngle := StrToInt(Parameters[3]) ;
{ if Parameters.High >= 4 then
InitialOrient := StrToInt(Parameters[4]) else}
if DoPeano then InitialOrient := false else InitialOrient := true;
{ setup Window, Window.Open }
Window.OnRender := @Render;
Window.OnResize := @Resize2D;
Window.DoubleBuffer := true;
Window.OnCloseQuery := @CloseQueryNotAllowed;
Window.ParseParameters(StandardParseOptions);
Window.SetDemoOptions(K_F11, CharEscape, true);
Window.Open;
{ init CurveImage }
CurveImage := TRGBImage.Create(Window.Width, Window.Height);
try
CurveImage.Clear(CurveImageBGCol);
{ calculate StepsToRedisplay i StepSize pomagajac sobie StepsResolution i
AllStepsCount }
if DoPeano then
StepsResolution := NatNatPower(3, Level) else
StepsResolution := Cardinal(1) shl Level;
AllStepsCount := Sqr(StepsResolution);
StepXSize := Max(1, CurveImage.Width div StepsResolution);
StepYSize := Max(1, CurveImage.Height div StepsResolution);
StepsToRedisplay := Max(1, Round(AllStepsCount / 20));
//StepsToRedisplay := 1;
{ draw the curve }
if DoPeano then
PeanoCurve(InitialOrient, InitialAngle, Level, @Step, nil) else
HilbertCurve(InitialOrient, InitialAngle, Level, @Step, nil);
{ show the window }
Window.Invalidate;
Window.OnCloseQuery := nil;
Application.Run;
finally FreeAndNil(CurveImage) end;
end.
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