[XNA]Drawing a simple transparent plane - xna

Question

I'm working with XNA and a have a problem.
A basic problem, but argh !!!
I want to draw a ocean, BASIC ocean, just a plane, blue and transparent.
just a plane.
I have try with Vertex, with models and textures.
How tha alpha channel work in XNA ? StencilState, DepthBuffer, nothing would work.
Can you explain how to do this ?
Use VertexPositionColor enough ?
Excuse me, but I am looking for a long time.
class Ocean
{
Effect shader0;
public Vector3 Position;
GraphicsDevice Graphics;
Camera camera;
Model Mesh;
Texture2D waterTexture;
Rectangle screen;
Texture2D test;
public Ocean(Vector3 pos, int size, GraphicsDevice gra, Camera cam, ContentManager content)
{
Graphics = gra;
shader0 = content.Load<Effect>("Ocean");
//shader0 = new BasicEffect(this.Graphics);
waterTexture = content.Load<Texture2D>("Images/shaderUnderwater");
screen = new Rectangle(0, 0, this.Graphics.Viewport.Width, this.Graphics.Viewport.Height);
Position = pos;
Mesh = content.Load<Model>("Models/ocean");
camera = cam;
foreach (ModelMesh mesh in this.Mesh.Meshes)
{
foreach (ModelMeshPart part in mesh.MeshParts)
{
part.Effect = shader0;
}
}
}
bool underWater;
Vector3 lightDirection = new Vector3(-1.0f, -1.0f, -1.0f);
public void Draw(SpriteBatch spriteBatch, Player player)
{
Matrix world = Matrix.CreateScale(100f) * Matrix.CreateRotationX(MathHelper.ToRadians(-90f)) * Matrix.CreateTranslation(Position);
//this.shader0.EnableDefaultLighting();
this.shader0.Parameters["World"].SetValue(world);
this.shader0.Parameters["View"].SetValue(player.Camera.View);
this.shader0.Parameters["Projection"].SetValue(player.Camera.Projection);
// Dessin du model
foreach (ModelMesh mesh in this.Mesh.Meshes)
{
foreach (Effect effect in mesh.Effects)
{
effect.CurrentTechnique = effect.Techniques["Textured"];
effect.Parameters["DiffuseColor"].SetValue(new Vector4(1f, 0.2f, 0.2f, 1f) ); // a reddish light
effect.Parameters["DiffuseLightDirection"].SetValue(new Vector3(1, 0, 0) ); // coming along the x-axis
effect.Parameters["SpecularColor"].SetValue(new Vector4(0, 1, 0 ,1f) ); // with green highlights
effect.Parameters["World"].SetValue(world);
effect.Parameters["View"].SetValue(player.Camera.View);
effect.Parameters["Projection"].SetValue(player.Camera.Projection);
}
mesh.Draw();
}
this.Graphics.BlendState = BlendState.Opaque;
//Effet
if (camera.Position.Y < Position.Y)
spriteBatch.Draw(this.waterTexture, this.screen, Color.White);
}
public void Update(GameTime gameTime)
{
}
void onWater()
{
underWater = true;
}
}
}

Answer 1

If you are using the BasicEffect to render the ocean, then BasicEffect has an Alpha property, which affects the transparency. Please see here: http://msdn.microsoft.com/en-us/library/microsoft.xna.framework.graphics.basiceffect.alpha.aspx
You can use BasicEffect to create transparency with any way that you are using for rendering your model.