XNA 2D particles problem

Summary:

The 2D particles tutorial, how to have it emitting from multiple sources at the same time?

XNA 2D particles problem

Fiona (guest) 21 Mar 2015 07:15

The 2D particles tutorial, how to have it emitting from multiple sources at the same time? I tried to put it in a loop for different positions, both with particleEngine.Update() and without.

With, the particles are updating way too fast, making everything move a lot faster than intended
Without, the particles goes to the last set position (makes sense), and leave the other ones without any particles.

Any solutions appreciated

Re: XNA 2D particles problem

Koljan 21 Mar 2015 18:38

If i understand correctly, you should create a ParticleEngine object for every source you need.
I don't think it's designed to work any other way. But you can always edit ParticleEngine class if you need it…

Re: XNA 2D particles problem

Marcus42 21 Mar 2015 18:36

Hi, Fiona.

If you want to get particles to come from multiple different locations, the easiest thing to do would be creating another instance of the ParticleEngine class. So you'd need to make another copy of this line here:
ParticleEngine particleEngine;
but change the name particleEngine to something new, like particleEngine2. Then you'd need to go through all of the code that references particleEngine and make another copy of it and change it to reference particleEngine2. To actually get the particles to come from a different location, change the EmitterLocation variable for particleEngine2, and you're done!
Here's what this might look like in your main class:

namespace ParticleEngine2D
{
    public class Game1 : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;
        ParticleEngine particleEngine;
        ParticleEngine particleEngine2;

        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
        }

        protected override void Initialize()
        {
            base.Initialize();
        }

        protected override void LoadContent()
        {
            spriteBatch = new SpriteBatch(GraphicsDevice);

            List<Texture2D> textures = new List<Texture2D>();
            textures.Add(Content.Load<Texture2D>("circle"));
            textures.Add(Content.Load<Texture2D>("star"));
            textures.Add(Content.Load<Texture2D>("diamond"));
            particleEngine = new ParticleEngine(textures, new Vector2(400, 240));
            particleEngine2 = new ParticleEngine(textures, new Vector2(400, 240));
        }

        protected override void UnloadContent()
        {
        }

        protected override void Update(GameTime gameTime)
        {
            // Allows the game to exit
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();

            particleEngine.EmitterLocation = new Vector2(Mouse.GetState().X, Mouse.GetState().Y);
            particleEngine.Update();

            particleEngine2.EmitterLocation = new Vector2(Mouse.GetState().X + 200, Mouse.GetState().Y + 200);
            particleEngine2.Update();

            base.Update(gameTime);
        }

        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.Black);

            particleEngine.Draw(spriteBatch);

            particleEngine2.Draw(spriteBatch);

            base.Draw(gameTime);
        }
    }
}

Hope this helps!

peorrt (guest) 12 Sep 2015 09:52

And using simply adding a new constructor with parameters for source emitter (or a setting method), then using a List,Array, etc. of particle engines intialised in different positions? modifiying the class to add an object of the same nature with only a tiny difference and not a well use of the encapsulation in OO; add a new feature to the object (ability to set the origin position for the particles), in constructor, methods, etc. then use the usual mechanisms of the language to have several objects.