#include "tricorn.h"

static const float convergenceLimit = 2.0f; // Mandelbrot set limit
static unsigned converge(float complex position,unsigned n);

void tricorn(float complex start, size_t width, ssize_t height, float res, unsigned n, _Bool color, unsigned char* img){
    
    // Absolute height for iteration purposes
    height = height < 0 ?  height*-1 : height;

    // Simple iteration over every pixel in the picture
    for(size_t i = 0; i < width; i++){
        for(ssize_t j = 0; j < height; j++){

            unsigned value = converge(start + (i*res - I*j*res),n);

            // Pixel value position in the output array
            size_t position = (j*width +i) *3;


            if(!color){ // Grayscale colors as specified by the assignment r = g = b
                img[position] =  value;
                img[position + 1] = value;
                img[position + 2] = value;
            }
            else{ // Temporary colors with random multipliers
                img[position] = ((value*3) % 255);
                img[position + 1] = ((value*2) % 255) ;
                img[position + 2] = ((value*5) % 255);
            }

        }
    }
}

// Iterative application of the equation given by the assignment
static unsigned converge(float complex position,unsigned n){

    complex float result  = 0;
    for(unsigned i = 0; i < n; i++){
        // Application of the given complex equation with m = 2
        result = cpowf(conjf(result),2) + position;

        // Detection of unbounded behaviour
        // If the magnitude of the result vector is greater than the convergence limit, we know that the function will grow unbounded
        // Current convergence limit taken from mandelbrot set
        if(sqrtf(powf (crealf(result),2)+powf(cimagf(result),2)) > convergenceLimit)
            return 255-4*(i % 64);
    }
    return 0;
}