HLSL Shaders

Summary:

I just want to see what other people have done.

HLSL Shaders

EmpiresBane 08 Sep 2011 21:12

The Shader tutorials here are a fairly good place to start off with. The actual shaders you make aren't all that great, but they can be easily expanded. I just want to know what you guys have done with them.

So far, all I have done is make the ambient light also take into account the texture below it. Before, anything not covered by the specular light would be a solid color. But now it seems a little weird because ambient light isn't affected by the bump map, so it loses it's detail on the side away from the light.
I just changed this:

return saturate(textureColor * (diffuseIntensity) + AmbientColor * AmbientIntensity + specular);

to this:

return saturate((textureColor * diffuseIntensity) + (textureColor * AmbientColor * AmbientIntensity) + specular);

EDIT: After modifying the code to rotate the model instead of the camera, it doesn't really look all that bad, so long as you keep the ambient light down.

Last edited on 08 Sep 2011 22:00 by EmpiresBane Show more

Re: HLSL Shaders

rbwhitaker 09 Sep 2011 00:49

Heh, heh. You're right, the shaders in the shader tutorials are all pretty basic. I could go on and on with additional tutorials about cooler shaders (and in fact, I intend on doing that, to some degree) but the most important thing is to provide you with the tools you need to know how to make any shader you can dream up, and I think my tutorials accomplish that, for the most part.

I've made a couple of shaders that do glass, water, and fur (that one is one I'd like to put on here before too long). I've also done a pixel shader to do blur, and one to do bloom (making the bright spots bleed into the area around them).

Like you, EmpiresBane, I'd love to hear what other people are doing with shaders!

Re: HLSL Shaders

EmpiresBane 11 Sep 2011 19:38

Is there any way to access the model's texture without loading it separately? I know it's already loaded somewhere, I just don't know how to get it. It would make things a little easier.

Re: HLSL Shaders

rbwhitaker 14 Sep 2011 01:08

Yes there's a way! You have to do a lot of digging though. The model geometry itself doesn't have a reference to it, but when you first load the model, the model has a reference to the effect (BasicEffect, by default) that is being used to draw it, which, in turn, has a reference to the texture. Notice, though, that this is assigned on a ModelMeshPart basis, so you will have to dig around to find the texture you want, or write a couple of loops to grab them all.

Model model = Content.Load<Model>("Helicopter");
Texture2D embeddedTexture = ((BasicEffect)model.Meshes[0].MeshParts[0].Effect).Texture;

So, yeah, what you're getting at is that you should not actually need to load the texture multiple times (once through the model, and once on your own, because you want to be able to use the texture) in order to get access to it. This should make it so you don't need to.

This, also, should make it so you can get the texture you want without that "Asset was built two times with different settings" warning.

Re: HLSL Shaders

rbwhitaker 14 Sep 2011 01:21

Better than that, here's an extension method that I threw together that will go in and do all of this work, finding all of the textures the model has. So add this to a new file called ModelExtensionMethods.cs (or whatever):

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework.Graphics;
 
namespace TextureExtractionTest // Uh... this is probably not the best namespace, permanently...
{
    /// <summary>
    /// A class containing extension methods for the Model class.
    /// </summary>
    public static class ModelExtensionMethods
    {
        /// <summary>
        /// Digs into the model and finds all of the Texture2D objects that it is currently using.
        /// Note that you must call this before making changes to the model's effects, or it may
        /// no longer be valid.
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        public static List<Texture2D> ListAllTextures(this Model model)
        {
            // This list will contain all of the textures the model has.
            List<Texture2D> textures = new List<Texture2D>();
 
            // Dig down into each of the model's meshes's mesh parts...
            foreach(ModelMesh mesh in model.Meshes)
            {
                foreach (ModelMeshPart part in mesh.MeshParts)
                {
                    // Grab the mesh part's effect.
                    Effect effect = part.Effect;
 
                    // If it isn't a basic effect, we've got some problems, because
                    // someone has been messing with it.  We won't be able to recover
                    // textures, so throw an exception.
                    if (!(effect is BasicEffect))
                    {
                        throw new InvalidOperationException("cannot list textures if model contains effects other than BasicEffect");
                    }
 
                    // Finally!  We have the texture we came for.
                    Texture2D texture = ((BasicEffect)effect).Texture;
 
                    // Only add it to the list if it isn't already there, so that we avoid duplicates. 
                    if (!textures.Contains(texture))
                    {
                        textures.Add(texture);
                    }
                }
            }
 
            return textures;
        }
    }
}

Now, you can simply call Model.ListAllTextures(); to get all of the textures. But you have to make that method call before you mess with the BasicEffect object, or change it to a different one (like an HLSL effect of your own creation).