Question

I was messing around with some triangles and made this. At first, I thought, all the “methods” I wrote were instantiated but those “methods” : device, content and effect; are actually all nulls. The code is almost fine, what was I supposed to write instead of those?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;

namespace Learning_Test1
{
class Triangle
{
    GraphicsDevice device;
    ContentManager content;
    Effect effect;

    VertexPositionColor[] vertices;

    public void bob()
    {
        content.RootDirectory = "Content";
        content.Load<Effect>("effects");
    }

    public void Initialize()
    {
        vertices = new VertexPositionColor[3];

        vertices[0].Position = new Vector3(1, 0, 0);
        vertices[0].Color = Color.Red;

        vertices[1].Position = new Vector3(0, 0, 1);
        vertices[1].Color = Color.Green;

        vertices[1].Position = new Vector3(-1, 0, 0);
        vertices[1].Color = Color.Blue;
    }

    public void Update()
    {
    }

    public void Draw()
    {
        effect.CurrentTechnique = effect.Techniques["PretransformedPS"];

        foreach (EffectPass pass in effect.CurrentTechnique.Passes)
        {
            pass.Apply();
        }

        device.DrawUserPrimitives(PrimitiveType.TriangleList, vertices, 0, 1, VertexPositionColor.VertexDeclaration);
    }
}

}

Answer 1

Well the only thing that you are actually initializing is your “vertices” array. I dont see where you actually attempt to initialize the other variables, unless you didnt include some code in your question, for example where you actually call your

Triangle testTriangle =  new Triangle();

You should initialize the rest of your class variables, device, content, and effect in your class’s initialize function unless you plan on setting them elsewhere. It’s been a little while since I last used XNA but if I remember correctly Device and Content might be initialized for you when you create a new game template so all you would have to do is set them equal to testTriangle.Device and testTriangle.Content. If not I would highly recommend looking at the tutorials on the XNA site as they are fantastic and I am 100% sure that you will be able to figure out how to initialize them from there.