/*
 * This software is delivered as the Deliverable D2.3 of the ANR
 * project Continuum, Ref. Number ANR-15-CE25-0007.
 *
 * D2.3 - Illustration of system reconfiguration due to varying
 * conditions: same-island, and migration
 *
 * Author: Erven ROHOU
 * Copyright (c) Inria
 *
 * License: GNU AFFERO GENERAL PUBLIC LICENSE v3
 *
 */

#include <stdio.h>
#include <string.h>

#define max(a, b)               \
  ({ __typeof__ (a) _a = (a);   \
    __typeof__ (b) _b = (b);    \
    _a > _b ? _a : _b; })

#define min(a, b)               \
  ({ __typeof__ (a) _a = (a);   \
    __typeof__ (b) _b = (b);    \
    _a < _b ? _a : _b; })

static const int ball_size = 5;
static unsigned char bg = 0;    // black


void pong_init(unsigned char* frame, int w, int h)
{
}

void pong_next(unsigned char* frame, int w, int h)
{
  static int x = 0;
  static int y = 0;
  static int dx = 1;
  static int dy = 1;

  memset(frame, bg, w*h*4);

#if 0
  // Delete previous position
  for(int i = max(0, x-ball_size); i <= min(w-1, x+ball_size); i++) {
    for(int j = max(0, y-ball_size); j <= min(h-1, y+ball_size); j++) {
      frame[(j * w + i) * 4 + 0] = bg;
    }
  }
#endif

  // Move ball
  x += dx;
  y += dy;
  if ((x == 0) || (x == w-1))
    dx = -dx;
  if ((y == 0) || (y == h-1))
    dy = -dy;

  // Draw new position
  for(int i = max(0, x-ball_size); i <= min(w-1, x+ball_size); i++) {
    for(int j = max(0, y-ball_size); j <= min(h-1, y+ball_size); j++) {
      frame[(j * w + i) * 4 + 0] = 255;  // red
   }
  }
}