fractal.cpp

#include "../Lib110ct.h"
void fractalMode(Win110ct& win);
void fractal(SDL_Surface *surf, int width, int height, double x, double y, double w, double h, int type, int maxiter, int shader);
int main(int argc, char** argv){
  // Gets the window of size 800x600
    Win110ct win(800,600,16); //this was actually one of my uni assignments, had to use their lib
    int mode = 0;
	fractalMode(win);
    return 0;
}
void fractalMode(Win110ct& win){
	//Gets the surface of the window and clear the text
    SDL_Surface *surf = win.getGraphics();
    win.clear();
    win.setPosition(0,0);
	//Continuously loop an wait for a new command to be pressed
    while(true){
        static double width = 4;
        static double height = 3;
        static double x = 0;
        static double y = 0;
        static int iter = 8;
        static int shader = 1;
        static int type = 4;
        fractal(surf, 800, 600, x, y, width, height,type, iter, shader);//Draws the fractal
		win.render();//Renders the fractal
        char cmd = win.getchar();
        win.setPosition(0,0);
        win.setEcho(false);
		//Exit the loops
        if(cmd == 'x') break;
		//Zooms in
        else if(cmd == 'i'){ width *= 0.7; height *= 0.7;}
		//Zooms out
        else if(cmd == 'o'){ width /= 0.7; height /= 0.7; }
		//Change the shader forward 1
        else if(cmd == 'n'){ shader++;}
		//Changes the shader back 1
		else if(cmd == 'm'){shader--;}
		//Add an iteration
        else if(cmd == 'j'){iter++;}
		//subtract an iteration
        else if(cmd == 'k'){iter--;}
		//Move the screen up
        else if(cmd == 'w'){y -= height/5;}
		//Move the screen down
        else if(cmd == 's'){y += height/5;}
		//Move the screen left
        else if(cmd == 'a'){x -= width/5;}
		//move the screen right
        else if(cmd == 'd'){x += width/5;}
		//Change the Julia values forward 1 type
        else if(cmd == 't'){type++;}
		//Change the julia values back 1 type
        else if(cmd == 'y'){type--;}
    }}
void fractal(SDL_Surface *surf, int width, int height, double x, double y, double w, double h, int type, int maxiter, int shader){
    SDL_Rect p;
    p.x, p.y = 0;//sets the first pixel location
    p.w, p.h = 1;//sets the size of the pixel
	//sets the default calculation values for the Julia set, cRe if A real value, and cIm is an imaginary number
    double cRe=-0.03515;
    double cIm=-0.07467;
	//switchs between the different julia set values
    switch (type){
            case 1: cRe=-0.70176; cIm= -0.3842; break;
            case 2: cRe= -0.835; cIm= -0.2321 ;break;
            case 3: cRe= -0.4; cIm= 0.6; break;
            case 4: cRe= 0.285; cIm= 0; break;
            case 5: cRe= -0.8; cIm= 0.156; break;
            case 6: cRe=0.233; cIm=0.5378;
            default: cRe=-0.4; cIm=0.6; break;
        }
	//iterates through every pixel on the screen
    for(p.y = 0; p.y < height; ++p.y)
        for(p.x = 0; p.x < width; ++p.x){
            double beforeA = (double)p.x/(double)width * w - (w/2) + x; //initial calculation for the pixels
            double beforeB = (double)p.y/(double)height * h - (h/2) + y;
            int i = 0; //Is keeping track of iterations
            while(beforeA*beforeA + beforeB*beforeB < 4 && i++ < maxiter){ //calculates the next value for the pixel
                double afterA = beforeA*beforeA - beforeB*beforeB + cRe;
                double afterB = 2 * beforeA * beforeB + cIm;
				//stores the new value for next loop
                beforeA = afterA;
                beforeB = afterB;
            }
            unsigned char shade_colour;
            switch(shader){//selects the shading type
                case 1: shade_colour = (beforeB/8) * (beforeA/4) * 255; break;
                case 2: shade_colour = 64/(beforeA*beforeA * beforeB/beforeB); break;
                case 3: shade_colour = (beforeA + beforeB) * 16; break;
                case 4: shade_colour = 255 - (double)i/maxiter * 255; break;
                default: {
                    if(beforeA*beforeA + beforeB*beforeB < 4)
                    shade_colour = 255;
                    else
                    shade_colour = 0;
                }}
            SDL_FillRect(surf, &p, (shade_colour << 24 | shade_colour << 16 | shade_colour << 8 | shade_colour));//draws the pixel
        }}