// Fraktale - zbior Drapiezny ptak (Bird of prey) wyzsze rzedy plonacego statku
// www.algorytm.org
// Tomasz Lubinski (c) 2009
//---------------------------------------------------------------------------

#include <vcl.h>
#include <math.h>
#pragma hdrstop
#include "Bird_Of_Prey.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}

#define MIN(a,b) ((a<b)?a:b)
#define MAX(a,b) ((a>b)?a:b)

//---------------------------------------------------------------------------
//Describes places to render
double ratioX, ratioY;
double minX, minY, maxX, maxY;
int downX, downY;
//colors
typedef struct RGBColors
{
   Byte r;
   Byte g;
   Byte b;
} TRGBColors;
TRGBColors colors[121];
//---------------------------------------------------------------------------

//for HSV colors
void HSV2RGB(float hue, float sat, float val, float &red, float &grn, float &blu)
{
int i;
float f, p, q, t;
if(val==0) {red=0; grn=0; blu=0;}
else{
 hue/=60;
 i = (int)(hue);
 f = hue-i;
 p = val*(1-sat);
 q = val*(1-(sat*f));
 t = val*(1-(sat*(1-f)));
 if (i==0) {red=val; grn=t; blu=p;}
 else if (i==1) {red=q; grn=val; blu=p;}
 else if (i==2) {red=p; grn=val; blu=t;}
 else if (i==3) {red=p; grn=q; blu=val;}
 else if (i==4) {red=t; grn=p; blu=val;}
 else if (i==5) {red=val; grn=p; blu=q;}
}
}

//initialize array with colors used to color different levels
void initializeColors()
{
        int level;
        float r, g, b;

        for (level=1; level<120; level++)
        {
                HSV2RGB(0, 1, 0.208*log(level), r, g, b);
                colors[level].r = (int)(r*255);
                colors[level].g = (int)(g*255);
                colors[level].b = (int)(b*255);
        }
        colors[120].r = 0;
        colors[120].g = 0;
        colors[120].b = 0;
}

//type for complex numbers
typedef struct complex_type
{
        double real;
        double imaginary;
} complex_t;

//calculate squared modus of given complex c
double complexModSq(complex_t c)
{
        return c.real*c.real + c.imaginary*c.imaginary;
}

//function z[0]=0
complex_t f(complex_t p)
{
        p.real = 0;
        p.imaginary = 0;
        return p;
}

//calculates (|Re{z[n]}| + i|Im{z[n]|)^level
complex_t power(complex_t z, int level)
{
        complex_t result, tmp;
        int i;

        z.real = fabs(z.real);
        z.imaginary = fabs(z.imaginary);

        result = z;
        for (i=1; i<level; i++)
        {
                tmp.real = result.real*z.real - result.imaginary*z.imaginary;
                tmp.imaginary = result.real*z.imaginary + result.imaginary*z.real;
                result = tmp;
        }

        return result;
}

//function z[n+1] = (|Re{z[n]}| + i|Im{z[n]|)^level + p
complex_t g(complex_t z, int level, complex_t p)
{
        complex_t result;
        result = power(z, level);
        result.real += p.real;
        result.imaginary += + p.imaginary;
        return result;
}

//value is inside set in the returned level
int levelSet(complex_t p, int level)
{
        complex_t z;
        int iteration;

        iteration = 0;
        z = f(p);

        do
        {
                z = g(z, level, p);
                iteration++;
        } while (complexModSq(z) < 4 && iteration < 120);

        return iteration;
}

//generate fractal
void __fastcall TForm1::Button1Click(TObject *Sender)
{
        int i, j, level, powLevel;
        complex_t p;
        Byte *pixel;

        minX = StrToFloat(minx->Text);
        minY = StrToFloat(miny->Text);
        maxX = StrToFloat(maxx->Text);
        maxY = StrToFloat(maxy->Text);

        powLevel =  powerLevel->ItemIndex + 2;

        ratioX = (maxX - minX) / Fractal->Width;
        ratioY = (maxY - minY) / Fractal->Height;

        Fractal->Canvas->Brush->Color = clWhite;
        Fractal->Canvas->Rectangle(0, 0, Fractal->Width, Fractal->Height);
        Fractal->Picture->Bitmap->PixelFormat = pf32bit;

        for (i=0; i<Fractal->Height; i++)
        {
                pixel = (Byte *)Fractal->Picture->Bitmap->ScanLine[i];
                p.imaginary = i*ratioY + minY;
                for (j=0; j<Fractal->Width; j++)
                {
                        p.real = j*ratioX + minX;
                        level = levelSet(p, powLevel);
                        *pixel = colors[level].b;
                        pixel++;
                        *pixel = colors[level].g;
                        pixel++;
                        *pixel = colors[level].r;
                        pixel++;
                        pixel++;
                }
        }
        Fractal->Refresh();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormCreate(TObject *Sender)
{
        minx->Text = FloatToStr(-2);
        maxx->Text = FloatToStr(1.5);
        miny->Text = FloatToStr(-2);
        maxy->Text = FloatToStr(1.5);

        minX = StrToFloat(minx->Text);
        minY = StrToFloat(miny->Text);
        maxX = StrToFloat(maxx->Text);
        maxY = StrToFloat(maxy->Text);

        ratioX = (maxX - minX) / Fractal->Width;
        ratioY = (maxY - minY) / Fractal->Height;

        //initialize array with colors
        initializeColors();

        //render new fractal
        Button1Click(Sender);
}

//---------------------------------------------------------------------------
void __fastcall TForm1::FractalMouseDown(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{
        downX = X;
        downY = Y;

        Selection->Width = 0;
        Selection->Height = 0;
        Selection->Visible = true;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FractalMouseUp(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{
        //remove selection
        Selection->Visible = false;

        //get new range to render
        minx->Text = FloatToStr(MIN(downX, X)*ratioX + minX);
        maxx->Text = FloatToStr(MAX(downX, X)*ratioX + minX);
        miny->Text = FloatToStr(MIN(downY, Y)*ratioY + minY);
        maxy->Text = FloatToStr(MAX(downY, Y)*ratioY + minY);

        minX = StrToFloat(minx->Text);
        minY = StrToFloat(miny->Text);
        maxX = StrToFloat(maxx->Text);
        maxY = StrToFloat(maxy->Text);

        //render new fractal
        Button1Click(Sender);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FractalMouseMove(TObject *Sender,
      TShiftState Shift, int X, int Y)
{
        //if left mouse button is held then draw selection
        if (Shift.Contains(ssLeft))
        {
                Selection->Width = abs(downX - X);
                Selection->Height = abs(downY - Y);
                Selection->Left = Fractal->Left + MIN(downX, X);
                Selection->Top = Fractal->Top + MIN(downY, Y);
        }
}
//---------------------------------------------------------------------------