{

// Reklame-skilt som markerer banen bilen kan kjøre på.

// Inneholder en nøstet struct for å holde styr på transformasjonen til hver enkelt plakat

// når den skal tegnes.

public class Obstacle

{

// Lagrer posisjon, rotasjon rundt y-aksen, samt tekstur for hver plakat.

// Det er kun implementert bruk av samme tekstur i denne versjonen.

private struct Instance

{

public Vector3 Position { get; set; }

public float rotY { get; set; }

public int texture;

}

// Vertekstabell, indekstabell, effekt, device, world-matrise.

private VertexPositionTexture[] vertices;

private int[] indices;

private BasicEffect effect;

private GraphicsDevice device;

private Matrix world = Matrix.Identity;

// Tekstur

private Texture2D texture;

// Tabell med alle individuelle posisjoner og rotasjoner.

private List<Instance> instances;

// Constructor

public Obstacle(GraphicsDevice device, ContentManager content)

{

// Sett device og effect (BasicEffect);

this.device = device;

effect = new BasicEffect(device);

// Last tekstur, klargjør BasicEffect for å vise tekstur

texture = content.Load<Texture2D>("reklame");

effect.Texture = texture;

effect.TextureEnabled = true;

// Sett opp vertekstabell og indekstabell

initVertices();

instances = new List<Instance>();

// Sett opp banen

initInstances();

}

private void initVertices()

{

// Sett opp koordinater og teksturkoordinater

vertices = new VertexPositionTexture[4];

vertices[0] = new VertexPositionTexture(new Vector3(-2, 0, 0), new Vector2(0.0f, 0.25f));

vertices[1] = new VertexPositionTexture(new Vector3(-2, 1, 0), new Vector2(0.0f, 0.0f));

vertices[2] = new VertexPositionTexture(new Vector3(2, 1, 0), new Vector2(1.0f, 0.0f));

vertices[3] = new VertexPositionTexture(new Vector3(2, 0, 0), new Vector2(1.0f, 0.25f));

// Trianglestrip

indices = new int[] { 3, 0, 2, 1 };

}

// Oppretter alle plakatene, legger dem i listen "instances"

private void initInstances()

{

// Sett opp ytre kvadrat med 20 x 20 plakater

for (int i = 0; i < 20; i++)

{

Instance instance = new Instance();

instance.Position = new Vector3(-50 + i * 4, 0, -50);

instance.rotY = 0;

instance.texture = 0;

instances.Add(instance);

Instance instance2 = instance;

instance2.rotY = MathHelper.Pi;

instance2.Position = new Vector3(-50 + i * 4, 0, 30);

instances.Add(instance2);

Instance instance3 = instance;

instance3.rotY = -MathHelper.PiOver2;

instance3.Position = new Vector3(28, 0, -48 + i * 4);

instances.Add(instance3);

Instance instance4 = instance;

instance4.rotY = MathHelper.PiOver2;

instance4.Position = new Vector3(-52, 0, -48 + i * 4);

instances.Add(instance4);

}

// Indre kvadrat, 14 x 14 plakater

for (int i = 0; i < 14; i++)

{

Instance instance = new Instance();

instance.Position = new Vector3(-38 + i * 4, 0, -38);

instance.rotY = 0;

instance.texture = 0;

instances.Add(instance);

Instance instance2 = instance;

instance2.rotY = MathHelper.Pi;

instance2.Position = new Vector3(-38 + i * 4, 0, 18);

instances.Add(instance2);

Instance instance3 = instance;

instance3.rotY = -MathHelper.PiOver2;

instance3.Position = new Vector3(16, 0, -36 + i * 4);

instances.Add(instance3);

Instance instance4 = instance;

instance4.rotY = MathHelper.PiOver2;

instance4.Position = new Vector3(-40, 0, -36 + i * 4);

instances.Add(instance4);

}

}

public void Draw(GameTime gameTime, Camera camera)

{

// Oppdater shaderen (world settes for hver plakat)

effect.View = camera.View;

effect.Projection = camera.Projection;

// Løp gjennom alle plakater

foreach (Instance instance in instances)

{

// ISROT for plakaten settes i World

Matrix rotation = Matrix.CreateRotationY(instance.rotY);

Matrix translation = Matrix.CreateTranslation(instance.Position);

effect.World = rotation * translation;

// Tegn forsiden

foreach (EffectPass pass in effect.CurrentTechnique.Passes)

{

pass.Apply();

device.DrawUserIndexedPrimitives(PrimitiveType.TriangleStrip, vertices, 0, vertices.Length, indices, 0, 2, VertexPositionTexture.VertexDeclaration);

}

// Tegner også plakaten på baksiden ved å beregne world-matrisa på nytt.

rotation = Matrix.CreateRotationY(instance.rotY - MathHelper.Pi);

effect.World = rotation * translation;

foreach (EffectPass pass in effect.CurrentTechnique.Passes)

{

pass.Apply();

device.DrawUserIndexedPrimitives(PrimitiveType.TriangleStrip, vertices, 0, vertices.Length, indices, 0, 2, VertexPositionTexture.VertexDeclaration);

}

}

}

}