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mandelbrot.c
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mandelbrot.c
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/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* mandelbrot.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: gmiyakaw <gmiyakaw@student.42.fr> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2022/11/23 13:09:50 by gmiyakaw #+# #+# */
/* Updated: 2022/12/20 14:51:16 by gmiyakaw ### ########.fr */
/* */
/* ************************************************************************** */
// The Mandelbrot Formula.
// From wikipedia, in pseudocode
// for each pixel (Px, Py) on the screen do
// x0 := scaled x coordinate of pixel (scaled to lie in the
// Mandelbrot X scale (-2.00, 0.47))
// y0 := scaled y coordinate of pixel (scaled to lie in the
// Mandelbrot Y scale (-1.12, 1.12))
// x := 0.0
// y := 0.0
// iteration := 0
// max_iteration := 1000
// while (x*x + y*y ≤ 2*2 AND iteration < max_iteration) do
// xtemp := x*x - y*y + x0
// y := 2*x*y + y0
// x := xtemp
// iteration := iteration + 1
#include "fractol.h"
// This functions runs the Mandelbrot formula in order to determine
// if a pixel is part of the set.
// MAX_ITERATION is modified by a variable that allows the user to
// change the "resolution" of the fractal. The more iterations a pixel
// is put through, the more accurate the fractal but also the number of
// calculations is also dramatically increased.
// 4 is considered to be the threshold value to determine if a
// point if part of the Mandelbrot set or not. If the value is
// ever past that, the function returns but also keeps track of
// how many iterations it took to get to that point as that will
// determine color assignment.
int is_mandelbrot(double cr, double ci, t_data *f)
{
double zr;
double zi;
double tmp;
int i;
i = 0;
zr = 0;
zi = 0;
while (i <= MAX_ITERATION + f->resolution_shift)
{
if ((zr * zr + zi * zi) > 4.0)
{
f->count = i;
return (0);
}
tmp = 2 * zr * zi + ci;
zr = zr * zr - zi * zi + cr;
zi = tmp;
i++;
}
f->count = i;
return (1);
}
// The functions loops through all lines and colums (y and x, respc.)
// for each pixel, it runs the equation a set number of time (MAX_ITER)
// if the value of the equation "escapes" towards infinity, the pixel
// is said to be outside the Mandelbrot set and will be assigned a color.
// Else, if it remains contained, it will be considered to be a part of
// the set and will be colored black. After going through all pixels
// the function pushes the image to the window.
void gen_mandelbrot(t_data *f)
{
int x;
int y;
double pr;
double pi;
y = -1;
while (++y < HEIGHT)
{
pi = f->max_i + ((double)y * (f->min_i - f->max_i) / HEIGHT);
x = -1;
while (++x < LENGTH)
{
pr = f->min_r + ((double)x * (f->max_r - f->min_r) / LENGTH);
if (is_mandelbrot(pr, pi, f) == 0)
my_px_put(f->img_data, x, y, make_color(f));
else
my_px_put(f->img_data, x, y, create_trgb(0, 0, 0, 0));
}
}
mlx_put_image_to_window(f->mlx, f->win, f->img_data->img, 0, 0);
return ;
}