#include <string.h></string.h>

#include <stdlib.h></stdlib.h>

#include <helianthus.h></helianthus.h>

#define WIDTH   64

#define HEIGHT  48

#define COUNT   256

#define CELL    16

typedef struct {

  int x, y, r;

} Point;

int matrix[HEIGHT][WIDTH];

Point order[ (HEIGHT*2 - 1)*(WIDTH*2 - 1) ];

void initOrder() {

  for(int y = 1-HEIGHT; y < HEIGHT; ++y) {

    for(int x = 1-WIDTH; x < WIDTH; ++x) {

      Point *p = &order[(y + HEIGHT - 1)*(WIDTH*2 - 1) + x + WIDTH - 1];

      p->x = x;

      p->y = y;

      int sector = x >= 0 && y > 0 ? 1

                 : y >= 0 && x < 0 ? 2

                 : x <= 0 && y < 0 ? 3

                 : y <= 0 && x > 0 ? 4

                 : 0;

      int subsector = sector % 2 ? abs(x) >= abs(y) : abs(y) >= abs(x);

      p->r = (x*x + y*y)*10 + sector*2 + subsector;

    }

  }

  int size = sizeof(order)/sizeof(*order);

  Point p;

  while(1) {

    int found = 0;

    for(int i = 1; i < size; ++i) {

      Point *p1 = &order[i], *p0 = p1 - 1;

      if (p0->r > p1->r) {

        memcpy(&p, p0, sizeof(p));

        memcpy(p0, p1, sizeof(p));

        memcpy(p1, &p, sizeof(p));

        found = 1;

      }

    }

    if (!found) break;

  }

}

void prepareMatrix(int x, int y) {

  if (x < 0) x = 0;

  if (x >= WIDTH) x = WIDTH-1;

  if (y < 0) y = 0;

  if (y >= HEIGHT) y = HEIGHT-1;

  memset(matrix, 0, sizeof(matrix));

  Point *p = order;

  for(int i = 0; i < COUNT; ++i) {

    int xx, yy;

    do {

      xx = x + p->x;

      yy = y + p->y;

      ++p;

    } while(xx < 0 || yy < 0 || xx >= WIDTH || yy >= HEIGHT);

    matrix[yy][xx] = 1;

  }

}

void init() {

  initOrder();

  windowSetSize(CELL*WIDTH, CELL*HEIGHT);

}

void draw() {

  noStroke();

  prepareMatrix(mouseX()/CELL, mouseY()/CELL);

  for(int y = 0; y < HEIGHT; ++y) {

    for(int x = 0; x < WIDTH; ++x) {

      fill( matrix[y][x] ? COLOR_BLUE : COLOR_LIGHTBLUE );

      rect(CELL*(x + 0.1), CELL*(y + 0.1), CELL*0.8, CELL*0.8);

    }

  }

}

int main() {

  windowSetVariableFrameRate(TRUE);

  windowSetInit(&init);

  windowSetDraw(&draw);

  windowRun();

  return 0;

}