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No indices object for reference

Started by ChristianFrantz May 31, 2013 at 5:36 AM 5 replies 1.5k views

Original Post

May 31, 2013 at 5:36 AM

When I'm creating a cube object in my class and trying to use my CreateVertexBuffer and CreateIndicesBuffer, I'm getting the error "object reference not set to an instance of an object". Even tho I'm creating the cube the right way, why is this happening?


public class Cube
{
    public GraphicsDevice device;

    const int number_of_vertices = 8;
    public const int number_of_indices = 36;

    public VertexBuffer vertices;
    public IndexBuffer indices;

    public Cube(GraphicsDevice graphicsDevice)
    {
        device = graphicsDevice;
    }

    public void CreateCubeVertexBuffer()
    {
        VertexPositionTexture[] cubeVertices = new VertexPositionTexture[number_of_vertices];

        "VERTICES HERE"

        vertices = new VertexBuffer(device, VertexPositionTexture.VertexDeclaration, number_of_vertices, BufferUsage.WriteOnly);
        vertices.SetData<VertexPositionTexture>(cubeVertices);
    }

    public void CreateCubeIndexBuffer()
    {
        UInt16[] cubeIndices = new UInt16[number_of_indices];

        "INDICES HERE"

        indices = new IndexBuffer(device, IndexElementSize.SixteenBits, number_of_indices, BufferUsage.WriteOnly);
        indices.SetData<UInt16>(cubeIndices);

    }

    public void Draw(BasicEffect effect)
    {

        foreach (EffectPass pass in effect.CurrentTechnique.Passes)
        {
            effect.CurrentTechnique.Passes[0].Apply();

            device.SetVertexBuffer(vertices);
            device.Indices = indices;

            device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, number_of_vertices, 0, number_of_indices / 3);
        }
    }
}
}

The error is at the line indices = new IndexBuffer(blah, blah, blah);

cube = new Cube(device);

cube.CreateCubeIndexBuffer();

cube.CreateCubeVertexBuffer();

Thats how I'm creating my cube. The reason for this is that I only want the buffers to be called once within the game to reduce lag

unbird

May 31, 2013 at 7:21 AM

Where do you call that ? If you do that in YourGame.LoadContent it should be fine (just checked).

Also: When reporting crashes, please show us the call stack (not everything usually a handful of frames is enough).

ChristianFrantz

May 31, 2013 at 7:34 AM

It is in my load content but it doesnt work

System.NullReferenceException was unhandled

Message=Object reference not set to an instance of an object.

Source=Microsoft.Xna.Framework.Graphics

StackTrace:

at Microsoft.Xna.Framework.Graphics.VertexBuffer.CreateBuffer(VertexDeclaration vertexDeclaration, UInt32 dwVertexCount, UInt32 usage, _D3DPOOL pool)

at Microsoft.Xna.Framework.Graphics.VertexBuffer..ctor(GraphicsDevice graphicsDevice, VertexDeclaration vertexDeclaration, Int32 vertexCount, BufferUsage usage)

at Cube_Chaser.Cube.CreateCubeVertexBuffer() in C:\Users\daj\Documents\Visual Studio 2010\Projects\Cube Chaser\Cube Chaser\Cube Chaser\Cube.cs:line 37

at Cube_Chaser.Cube..ctor(GraphicsDevice graphicsDevice) in C:\Users\daj\Documents\Visual Studio 2010\Projects\Cube Chaser\Cube Chaser\Cube Chaser\Cube.cs:line 117

at Cube_Chaser.Game1.Initialize() in C:\Users\daj\Documents\Visual Studio 2010\Projects\Cube Chaser\Cube Chaser\Cube Chaser\Game1.cs:line 61

at Microsoft.Xna.Framework.Game.RunGame(Boolean useBlockingRun)

at Microsoft.Xna.Framework.Game.Run()

at Cube_Chaser.Program.Main(String[] args) in C:\Users\daj\Documents\Visual Studio 2010\Projects\Cube Chaser\Cube Chaser\Cube Chaser\Program.cs:line 15

InnerException:

unbird

May 31, 2013 at 7:48 AM

Well, from that call stack it rather looks it's called in Initialize and it's the vertex buffer creation that fails. Works fine for me here even in Initialize. Please show the code of the whole body of Initialize. Or create a minimal project which reproduces the problem and upload it here, I take a look.

ChristianFrantz

May 31, 2013 at 7:51 AM


protected override void Initialize()
        {
            // TODO: Add your initialization logic here
            cube = new Cube(device);

            camera = new Camera(new Vector3(0.5f, 1.5f, 0.5f), 0, GraphicsDevice.Viewport.AspectRatio, 0.5f, 100f);
            effect = new BasicEffect(GraphicsDevice);
            cubes = new DrawableList<Cube>(this, camera, effect);
            device = GraphicsDevice;
            
            for (int x = 0; x < mapCoordsX; x++)
            {
                mapX[x] = x;
            }

            for (int z = 0; z < mapCoordsZ; z++)
            {
                mapZ[z] = z;
            }

            for (int y = 0; y < mapCoordsY; y++)
            {
                mapY[y] = y;
            }

            base.Initialize();
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            cube.CreateCubeVertexBuffer();
            cube.CreateCubeIndexBuffer();
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);
            font = Content.Load<SpriteFont>("font");
            grass = Content.Load<Texture2D>("grass");

            // TODO: use this.Content to load your game content here
            Components.Add(cubes);

            for (int x = 0; x < 50; x++)
            {
                for (int z = 0; z < 50; z++)
                {
                    cubes.Add(new Vector3(mapX[x], 0f, mapZ[z]), Matrix.Identity, grass);
                }
            }

            string mapString = reader.ReadToEnd();
        }

Here's both of the methods. Would it make sense to put the CreateBuffer methods in the constructor of the cube?

"cubes" is a drawable list made up of cubes

unbird

May 31, 2013 at 7:55 AM

Well, this is debugging 101. Your device = GraphicsDevice is happening after your cube = new Cube, so it is still null. Always look at the parameters in question if you have a crash.

ChristianFrantz

May 31, 2013 at 7:57 AM

Oh wow lol. Fps is still horrible but at least it works

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