2 replies to this topic

[Bonchenko]

hello, I am currently making a golf ball game using C# and XNA.
So far I have been able to make the ball fly, bounce, and roll, while displaying the position and velocity.
Now I want to be able to see the ball path (similar to images below), in order to check the whole ball movement.


My code updates the ball position at a fixed time interval. I am thinking of:
1) using these position,
2) insert them to an array of VertexPositionColor[],
3) and draw them using GraphicsDevice.DrawUserPrimitives<VertexPositionColor>() method

but I have no luck so far, the VertexPositionColor is static array, while the amount of position data is always increasing.

I am thinking of using List<VertexPositionColor>, but the GraphicsDevice.DrawUserPrimitives<VertexPositionColor>() method refuse to take that as an input

  protected override void Draw(GameTime gameTime) {
	    trail_vertice = new VertexPositionColor;
	    trail_vertice.Position = Position;
	    trail_vertice.Color = Color.Black;
	    trail_amount += 1;
	    trailList.Add(trail_vertice);
		   
	    basicEffect.CurrentTechnique.Passes[0].Apply();
		  graphics.GraphicsDevice.DrawUserPrimitives<VertexPositionColor>(PrimitiveType.LineStrip, trailList, 0, trail_amount);
	    }

I do not need an advanced effect like using particle engine. Just a single line is enough. Any suggestion?

Thanks in advance

[Digitalfragment]

List<VertexPositionColor> has a ToArray() function that will convert it to type VertexPositionColor[]

For the sake of speed though, i'd suggest keeping it as the array to begin with and just set it so its initailised with a predetermined maximum size, eg new VertexPositionColor[256]; If you go to add more verticies, and the array is full, then you can start treating it like a ring/circle buffer and forget the oldest points.

[Bonchenko]

Whoa, thanks for the hint. That solves the problem