Drawn enemy random on different position

Question

I would like to insert random enemies in the map in different positions. It's possible?

This is how i load image of enemy: Enemy.java:

public class Enemy {
    public Array<Sprite> enemy = new Array<Sprite>(2);  

    public void nemici() {
        Sprite mysterio;
        Sprite boss;
        enemy.add(mysterio = new Sprite(new Texture("mysterio.png")));
        enemy.add(boss = new Sprite(new Texture("boss.png")));
    }
}

And this is how i draw with my level1.java:

public class Level1 implements Screen{
    
    private Texture BackgroundLevel1;
    
    NameGame game;
    
    Sprite card;
    private Enemy enemies = new Enemy();
    
    public Level1 (NameGame game){
        this.game = game;
        
        enemies.nemici();
        card = enemies.enemy.random();
        
        BackgroundLevel1 = new Texture("BackgroundLevel1.png");
    }
    
    @Override
    public void show() {
    }

    @Override
    public void render(float f) {
        Gdx.gl.glClearColor(0, 0, 0, 0);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
        game.batch.begin();
        
        //Background
        game.batch.draw(BackgroundLevel1, 0, 0, NameGame.WIDTH, NameGame.HEIGHT);

        game.batch.draw(card,200,0,100,100);  //Example
        
        game.batch.end();
    }

Answer 1

The idea is to store the information of an enemy into a class instance. Here is the pseudo-code of what I have in mind.

I've added pseudo-comments to the pseudo-code to explain what's going on.

/**
 * This holds an enemy.
 */
class Enemy:
  Sprite sprite_;
  Vec2 size_;
  Vec2 position_;
  
  func Enemy(string spritePath, Vec2 size): // constructor
    sprite_ = new Texture(spritePath);
    size_ = size;
  
  
/**
 * You store all of the potential enemies here. All the enemies of the same type
 * share the same values for sprite and size. We don't fill the position 
 * because that is the level that will load it.
 */
static class EnemyFactory:
  Array<Enemy> enemies_;
  
  func EnemyFactory(): // constructor
    enemies_.add(new Enemy( "mysterio.png", new Vec2( 100,100 ) );
    enemies_.add(new Enemy( "boss.png", new Vec2( 100,100 ) );
  
  func GenerateOne(Vec2 position):
    Enemy newEnemy = enemies_.random().clone();
    newEnemy.position_ = position;
    return newEnemy;


class Level1:
  Array<Enemy> enemies_;
  
  func Level1(): // constructor
    ...
    // Start by defining all the potential spots where an enemy could spawn.
    // Ideally, you'll want to put this in an external file and load it when the
    // game starts. 
    Array<Vec2d> potentialPositions;
    potentialPositions.add( new Vec2d(..., ...) )
    potentialPositions.add( new Vec2d(..., ...) )
    potentialPositions.add( new Vec2d(..., ...) )
    potentialPositions.add( new Vec2d(..., ...) )
    potentialPositions.add( new Vec2d(..., ...) )
    potentialPositions.add( new Vec2d(..., ...) )
    potentialPositions.add( new Vec2d(..., ...) )
    
    // Create your enemies. Your enemy types have been defined in the 
    // EnemyFactory, so it's only a matter of selecting one and placing it using
    // what you've previously defined. 
    //
    // Note that we remove the positions once we've used it because we don't 
    // want more than one enemy at the same spot
    Vec2d enemyPosition = potentialPositions.random();
    potentialPositions.erase( enemyPosition ); 
    enemies_.add(EnemyFactory.GenerateOne( enemyPosition );
    
    enemyPosition = potentialPositions.random();
    potentialPositions.erase( enemyPosition );
    enemies_.add(EnemyFactory.GenerateOne( enemyPosition );

    enemyPosition = potentialPositions.random();
    potentialPositions.erase( enemyPosition );
    enemies_.add(EnemyFactory.GenerateOne( enemyPosition );
    ...
    
    
  func Render():
    ...
    for enemy in enemies_:
      // The data you need is stored in your class instance
      game.batch.draw(enemy.sprite_,enemy.position_,enemy.size_);
      
    ...