AVR Mandelbrot

/*
 * Mandelbrot.c
 *
 * Created: 12/7/2018 5:29:54 PM
 * Author : lucah
 */

#ifndef F_CPU
#define F_CPU 25000000
#endif

#include <avr/io.h>
#include <util/delay.h>
#include "ff.h"
#include "ata.h"

void beep(uint8_t b){
    uint8_t counter = 0;
    PORTD |= (1 << PD4);
    while (1)
    {
        PORTD |= (1 << PD4);
        if(b){
            _delay_ms(1.06);
        }else{
            //_delay_us(660);
            for(uint8_t i = 0; i < 33; i++) _delay_us(20);
        }
        PORTD &= ~(1 << PD4);
        if(b){
            _delay_ms(1.06);
        }else{
            //_delay_us(660);
            for(uint8_t i = 0; i < 33; i++) _delay_us(20);
        }
        counter++;
        if(counter >= 151) break;
    }
    PORTD &= ~(1 << PD4);
}

long HSBtoRGB(float hue, float saturation, float brightness){
    long r = 0, g = 0, b = 0;
    if(saturation == 0){
        r = g = b = (int) (brightness * 255.0f + 0.5f);
    }else{
        float h = (hue - (float)floor(hue)) * 6.0f;
        float f = h - (float)floor(h);
        float p = brightness * (1.0f - saturation);
        float q = brightness * (1.0f - saturation * f);
        float t = brightness * (1.0f - (saturation * (1.0f - f)));
        switch ((long) h) {
        case 0:
            r = (long) (brightness * 255.0f + 0.5f);
            g = (long) (t * 255.0f + 0.5f);
            b = (long) (p * 255.0f + 0.5f);
            break;
        case 1:
            r = (long) (q * 255.0f + 0.5f);
            g = (long) (brightness * 255.0f + 0.5f);
            b = (long) (p * 255.0f + 0.5f);
            break;
        case 2:
            r = (long) (p * 255.0f + 0.5f);
            g = (long) (brightness * 255.0f + 0.5f);
            b = (long) (t * 255.0f + 0.5f);
            break;
        case 3:
            r = (long) (p * 255.0f + 0.5f);
            g = (long) (q * 255.0f + 0.5f);
            b = (long) (brightness * 255.0f + 0.5f);
            break;
        case 4:
            r = (long) (t * 255.0f + 0.5f);
            g = (long) (p * 255.0f + 0.5f);
            b = (long) (brightness * 255.0f + 0.5f);
            break;
        case 5:
            r = (long) (brightness * 255.0f + 0.5f);
            g = (long) (p * 255.0f + 0.5f);
            b = (long) (q * 255.0f + 0.5f);
            break;
        }
    }
    return 0xff000000 | (r << 16) | (g << 8) | (b << 0);
}

int main(void)
{
    CLKPR = (1 << CLKPCE);
    CLKPR = 0;
    DDRD |= (1 << PD4);
    DDRB |= (1 << PB6);
    DDRB |= (1 << PB5);

    beep(0);

    uint8_t err = ata_init();
    if(err != 0){
        beep(1);
        while(1);
    }

    beep(0);

    static FATFS FATFS_obj;
    FRESULT f_err = f_mount(&FATFS_obj, "", 1);
    if(f_err != FR_OK){
        beep(1);
        while(1);
    }

    beep(0);

    static FIL outputFile;
    f_err = f_open(&outputFile, "mandelbrot.dat", FA_WRITE);
    if(f_err != FR_OK){
        beep(1);
        while(1);
    }

    beep(0);

    f_err = f_lseek(&outputFile, 0);
    f_err |= f_truncate(&outputFile);
    if(f_err != FR_OK){
        beep(1);
        while(1);
    }

    uint8_t colorBuffer[512 * 3];
    for(long i = 0; i < 512; i++){
        long rgb = HSBtoRGB((float)i/256.0f, 1.0f, (float)i/(i+8.0f));
        colorBuffer[i * 3 + 0] = (uint8_t)(rgb >> 16UL);
        colorBuffer[i * 3 + 1] = (uint8_t)(rgb >> 8UL);
        colorBuffer[i * 3 + 2] = (uint8_t)(rgb >> 0UL);
    }

    uint8_t dataBuffer[156];
    dataBuffer[0] = 1;
    int width = 1920;
    int height = 1080;
    dataBuffer[1] = (uint8_t)width;
    dataBuffer[2] = (uint8_t)(width >> 8);
    dataBuffer[3] = (uint8_t)height;
    dataBuffer[4] = (uint8_t)(height >> 8);

    UINT w = 0;

    f_write(&outputFile, dataBuffer, 5, &w);

    int posCntr = 0;
    float re = -0.235125;
    float imag = 0.827215;
    float r = 4.0e-5;
    //double re = 0;
    //double imag = 0;
    //double r = 1;

    const int maxIters = 512;
    float c_re;
    float c_im;
    float x;
    float x_new;
    float y;
    int iteration;
    const float c1 = 4.0/width*r;
    for(int row = 0; row < height; row++){
        if(row >= 360){
            PORTB |= (1 << PB5);
        }
        if(row >= 720){
            PORTB |= (1 << PB6);
        }
        for(int col = 0; col < width; col++){
            c_re = re + (col - width/2.0)*c1;
            c_im = imag + (row - height/2.0)*c1;
            x = 0; y = 0;
            iteration = 0;
            while(x*x+y*y <= 4 && iteration < maxIters){
                x_new = x*x - y*y + c_re;
                y = 2*x*y + c_im;
                x = x_new;
                iteration++;
            }
            if(iteration < maxIters){
                iteration %= 512;
                dataBuffer[posCntr] = colorBuffer[iteration * 3];
                dataBuffer[posCntr + 1] = colorBuffer[iteration * 3 + 1];
                dataBuffer[posCntr + 2] = colorBuffer[iteration * 3 + 2];
            }else{
                dataBuffer[posCntr] = 0;
                dataBuffer[posCntr + 1] = 0;
                dataBuffer[posCntr + 2] = 0;
            }
            PORTD ^= (1 << PD4);
            posCntr+=3;
            if(posCntr == 156){
                f_write(&outputFile, dataBuffer, 156, &w);
                posCntr = 0;
            }
        }
    }
    f_write(&outputFile, dataBuffer, posCntr, &w);

    f_close(&outputFile);
    f_unmount("");
    beep(0);
    while (1)
    {
    }
}