cpr.h

void spawn_foods(CCpr *env) {
  // After each step, check existing foods and spawns new food in the
  // neighborhood Iterates over food_list for efficiency instead of the entire
  // grid.
  FoodList *foods = env->foods;
  int original_size = foods->size;
  for (int i = 0; i < original_size; i++) {
    int idx = foods->indexes[i];
    int offset = idx - env->width - 1; // Food spawn in 1 radius
    int r = offset / env->width;
    int c = offset % env->width;
    for (int ri = 0; ri < 3; ri++) {
      for (int ci = 0; ci < 3; ci++) {
        int grid_idx = grid_index(env, (r + ri), (c + ci));
        if (env->grid[grid_idx] == EMPTY) {
          switch (env->grid[idx]) {
          // %Chance spawning new food
          case NORMAL_FOOD:
            if ((rand() / (double)RAND_MAX) < env->food_base_spawn_rate) {
              add_food(env, grid_idx, env->grid[idx]);
            }
            break;
          case INTERACTIVE_FOOD:
            if ((rand() / (double)RAND_MAX) <
                (env->food_base_spawn_rate / 10.0)) {
              add_food(env, grid_idx, env->grid[idx]);
            }
            break;
          }
        }
      }
    }
  }

  // Each turn there is random probability for a food to spawn at a random
  // location To cope with resource depletion
  int normalizer = (env->width * env->height) / 576;
  if ((rand() / (double)RAND_MAX) <
      min((env->food_base_spawn_rate * 2 * normalizer), 1e-2)) {
    spawn_food(env, NORMAL_FOOD);
  }
  if ((rand() / (double)RAND_MAX) <
      min((env->food_base_spawn_rate / 5.0 * normalizer), 5e-3)) {
    spawn_food(env, INTERACTIVE_FOOD);
  }
}