In this tutorial you will learn how to load a mesh in a program and additionally, how to obtain the mesh using blender.



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Game assets [2.3.2] for this tutorial:

• oak.blend
• oak.bcm
• bark.png
• leaf.png

Besides the using statements from the starter project, this tutorial needs the following using statements:

using BetaCell.Environment.Mesh;
using BetaCell.Environment.Mesh.Content;
using BetaCell.Common.Bounding;
using BetaCell.Environment;
using BetaCell.Environment.Mesh.Visitors;
using BetaCell.Environment.Light;
using BetaCell.Util.RenderStates;

The attributes that come with the starter project are explained in tutorial section 1.1.4.

For this tutorial we are going to be needing the following attributes:

BCMesh treeMesh;

BCAlphaGreaterRenderStrategy alphaBlock;

BetaCell can be extended to use any 3D mesh format, but out of the box, it supports the bcm (beta cell mesh) format. This is a new format and it's not supposed to replace or even compete with the already popular formats out there, it's just that the current formats have some undesired complications like:

• The free ones have no visible owner, this allowed different parties to create extensions over the time to a point where writing an importer for them is very difficult.
• The proprietary ones have a closed definition so writing an importer for them requires reverse engineering from the mesh files which is difficult.
• Some formats store information that's not commonly used in a BetaCell program, this makes them complicated and writing an importer for them is also very difficult. 

The purpose of the BCM file format is to be an intermediary between popular 3D content creation tools and BetaCell, nothing more. In this tutorial you will load an oak tree in blender, export it to a BCM mesh and finally load it in BetaCell. If you want to skip the blender part of the tutorial, you can just download the oakTree.bcm mesh file, the textures and skip to 3.2.5.


For example, I pasted it in the following folder:

D:\Program Files\Blender Foundation\Blender\.blender\scripts

Because I installed blender in:

D:\Program Files\Blender Foundation\Blender

Most of the parts of the initialize method were discussed in previous tutorials, the new part is how to load a mesh.

treeMesh = BCMeshReader.readMesh(
    "Content/gameAssets/oak",
    null,
    device,
    content
);

The read mesh method receives the path of the mesh without the extension from the content folder, a null parameter that will be explained later in the tutorials and the device and the content objects.

Notice that we create a color setter and a light setter but not a texture setter; that's because the mesh reader creates the texture effect, the feeder and the samplers from the BCM file. Also notice that the init method isn't called; that's because it's called in the readMesh method.

Finally we visit the mesh, note that we don't use a color setter, the mesh loader already adds this effect for us:

treeMesh.visit(lightSetter);

Here we draw the tree blocking alpha vales; this is useful to let the leafs be created with a texture.

alphaBlock.push(device);
treeMesh.Draw(gameTime);
alphaBlock.pop(device);

This is a very important tutorial, you can now create the content of your application using blender and load it using BetaCell. This tutorial is very shallow in the blender subject because that information is already in the web.

Click here to go to the forum discussion of this tutorial

using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.Storage;

using BetaCell.Debug;
using BetaCell.Util.GlobalInfo.Content;
using BetaCell.Environment.Camera;
using BetaCell.Util.GlobalInfo;

using BetaCell.Environment.Mesh;
using BetaCell.Environment.Mesh.Content;
using BetaCell.Common.Bounding;
using BetaCell.Environment;
using BetaCell.Environment.Mesh.Visitors;
using BetaCell.Environment.Light;
using BetaCell.Util.RenderStates;

namespace Starter
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class Game1 : Microsoft.Xna.Framework.Game
    {
        //Game attributes
        GraphicsDeviceManager graphics;
        GraphicsDevice device;
        ContentManager content;

        BCFirstPersonHumanCamera camera;
        //end game attributes

        //This tutorial's attributes
        BCMesh treeMesh;

        BCAlphaGreaterRenderStrategy alphaBlock;

        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            graphics.PreferredDepthStencilFormat = DepthFormat.Depth24Stencil8;
            content = new ContentManager(Services);
#if(XBOX360)
            graphics.PreferredBackBufferWidth = 1280;
            graphics.PreferredBackBufferHeight = 720;
#else
            graphics.PreferredBackBufferWidth = 852;
            graphics.PreferredBackBufferHeight = 480;
#endif
        }

        protected override void Initialize()
        {
            //base initialization
            device = graphics.GraphicsDevice;

            BCLogger.instance.init(device, content);
            BCInitializationManager.initialize(content);

            OnActivated(null, null);

            alphaBlock = new BCAlphaGreaterRenderStrategy();

            //Mesh
            treeMesh = BCMeshReader.readMesh(
                "Content/gameAssets/oak",
                null,
                device,
                content
            );

            //-----
            //Light Effect
            //-----

            BCBasicLight light = new BCBasicLight();
            light.range = 3000;
            light.transform = Matrix.CreateTranslation(-2.5f, -2.5f, 0);
            light.cubAtten = 0;
            light.constAtten = 0.4f;
            light.linAtten = 0.05f;
            light.useShadows = false;

            BCDynamicEffectVisitor lightSetter = new BCDynamicEffectVisitor(
                light.getFunction("Shader.Light.Classic.PixelDirectionLight"), light, 1
            );

            treeMesh.visit(lightSetter);

            base.Initialize();
        }

        protected override void OnActivated(object sender, EventArgs args)
        {
            buildViewMatrix();
            base.OnActivated(sender, args);
        }

        void buildViewMatrix()
        {
            Vector3 pos = new Vector3(6, 3.1f, 6);
            Vector3 look = new Vector3(-6, -1, -6);
            look.Normalize();

            camera = new BCFirstPersonHumanCamera(look, pos,
                MathHelper.PiOver4,
                (float)this.Window.ClientBounds.Width / (float)this.Window.ClientBounds.Height,
                1f, 200);

            BCGlobalInfo.instance.setMatrix(
                BCGlobalInfo.VIEW_INDEX,
                camera.getViewMatrix(-1)
            );

            BCGlobalInfo.instance.setMatrix(
                BCGlobalInfo.PROJECTION_INDEX,
                camera.getProjectionMatrix(-1)
            );
        }

        protected override void Update(GameTime gameTime)
        {
        }

        protected override void Draw(GameTime gameTime)
        {
            graphics.GraphicsDevice.Clear(ClearOptions.Target | ClearOptions.DepthBuffer, Color.White, 1.0f, 0);

            alphaBlock.push(device);
            treeMesh.Draw(gameTime);
            alphaBlock.pop(device);

            BCLogger.instance.printFPS(gameTime);
            BCLogger.instance.flush();
            base.Draw(gameTime);
        }
    }
}