//
// Created by love on 2024-01-18.
//

#pragma once

#include "SDL.h"


int roundUpToMultipleOfEight(int v) {
    return (v + (8 - 1)) & -8;
}

// https://stackoverflow.com/questions/38334081/how-to-draw-circles-arcs-and-vector-graphics-in-sdl
void DrawCircle(SDL_Renderer *renderer, SDL_Point &center, int radius) {
    // 35 / 49 is a slightly biased approximation of 1/sqrt(2)
    const int arrSize = roundUpToMultipleOfEight(radius * 8 * 35 / 49);
    SDL_Point points[arrSize];
    int drawCount = 0;

    const int32_t diameter = (radius * 2);

    int32_t x = (radius - 1);
    int32_t y = 0;
    int32_t tx = 1;
    int32_t ty = 1;
    int32_t error = (tx - diameter);

    while (x >= y) {
        // Each of the following renders an octant of the circle
        points[drawCount + 0] = {center.x + x, center.y - y};
        points[drawCount + 1] = {center.x + x, center.y + y};
        points[drawCount + 2] = {center.x - x, center.y - y};
        points[drawCount + 3] = {center.x - x, center.y + y};
        points[drawCount + 4] = {center.x + y, center.y - x};
        points[drawCount + 5] = {center.x + y, center.y + x};
        points[drawCount + 6] = {center.x - y, center.y - x};
        points[drawCount + 7] = {center.x - y, center.y + x};

        drawCount += 8;

        if (error <= 0) {
            ++y;
            error += ty;
            ty += 2;
        }

        if (error > 0) {
            --x;
            tx += 2;
            error += (tx - diameter);
        }
    }

    SDL_RenderDrawPoints(renderer, points, drawCount);
}