protected virtual Effect CreateBasicEffect(GLTFMATERIAL srcMaterial)
{
var dstMaterial = new BasicEffect(Device);
dstMaterial.Name = srcMaterial.Name;
dstMaterial.Alpha = GetAlphaLevel(srcMaterial);
dstMaterial.DiffuseColor = GetDiffuseColor(srcMaterial);
dstMaterial.SpecularColor = GetSpecularColor(srcMaterial);
dstMaterial.SpecularPower = GetSpecularPower(srcMaterial);
dstMaterial.EmissiveColor = GeEmissiveColor(srcMaterial);
dstMaterial.Texture = UseDiffuseTexture(srcMaterial);
if (srcMaterial.Unlit)
{
dstMaterial.EmissiveColor = dstMaterial.DiffuseColor;
dstMaterial.SpecularColor = Vector3.Zero;
dstMaterial.SpecularPower = 16;
}
dstMaterial.PreferPerPixelLighting = true;
dstMaterial.TextureEnabled = dstMaterial.Texture != null;
return(dstMaterial);
}
protected virtual Effect CreateRigidEffect(GLTFMATERIAL srcMaterial)
{
var dstMaterial = srcMaterial.Alpha == Schema2.AlphaMode.MASK
? CreateAlphaTestEffect(srcMaterial)
: CreateBasicEffect(srcMaterial);
return(dstMaterial);
}
private static Vector3 GeEmissiveColor(GLTFMATERIAL srcMaterial)
{
var emissive = srcMaterial.FindChannel("Emissive");
if (emissive == null)
{
return(Vector3.Zero);
}
return(new Vector3(emissive.Value.Color.X, emissive.Value.Color.Y, emissive.Value.Color.Z));
}
private static float GetSpecularPower(GLTFMATERIAL srcMaterial)
{
var mr = srcMaterial.FindChannel("MetallicRoughness");
if (mr == null)
{
return(16); // default value = 16
}
var metallic = mr.Value.GetFactor("MetallicFactor");
var roughness = mr.Value.GetFactor("RoughnessFactor");
return(4 + 16 * metallic);
}
private Texture2D UseDiffuseTexture(GLTFMATERIAL srcMaterial)
{
var diffuse = srcMaterial.FindChannel("Diffuse");
if (diffuse == null)
{
diffuse = srcMaterial.FindChannel("BaseColor");
}
if (diffuse == null)
{
return(null);
}
return(UseTexture(diffuse, null));
}
protected virtual Effect CreateAlphaTestEffect(GLTFMATERIAL srcMaterial)
{
var dstMaterial = new AlphaTestEffect(Device);
dstMaterial.Name = srcMaterial.Name;
dstMaterial.Alpha = GetAlphaLevel(srcMaterial);
//dstMaterial.AlphaFunction = CompareFunction.GreaterEqual;
dstMaterial.ReferenceAlpha = (int)(srcMaterial.AlphaCutoff * 255);
dstMaterial.DiffuseColor = GetDiffuseColor(srcMaterial);
dstMaterial.Texture = UseDiffuseTexture(srcMaterial);
return(dstMaterial);
}
private static Vector3 GetDiffuseColor(GLTFMATERIAL srcMaterial)
{
var diffuse = srcMaterial.FindChannel("Diffuse");
if (diffuse == null)
{
diffuse = srcMaterial.FindChannel("BaseColor");
}
if (diffuse == null)
{
return(Vector3.One);
}
return(new Vector3(diffuse.Value.Color.X, diffuse.Value.Color.Y, diffuse.Value.Color.Z));
}
private static float GetAlphaLevel(GLTFMATERIAL srcMaterial)
{
if (srcMaterial.Alpha == Schema2.AlphaMode.OPAQUE)
{
return(1);
}
var baseColor = srcMaterial.FindChannel("BaseColor");
if (baseColor == null)
{
return(1);
}
return(baseColor.Value.Color.W);
}
private static Vector3 GetSpecularColor(GLTFMATERIAL srcMaterial)
{
var mr = srcMaterial.FindChannel("MetallicRoughness");
if (mr == null)
{
return(Vector3.One); // default value 16
}
var diffuse = GetDiffuseColor(srcMaterial);
var metallic = mr.Value.GetFactor("MetallicFactor");
var roughness = mr.Value.GetFactor("RoughnessFactor");
var k = Vector3.Zero;
k += Vector3.Lerp(diffuse, Vector3.Zero, roughness);
k += Vector3.Lerp(diffuse, Vector3.One, metallic);
k *= 0.5f;
return(k);
}
protected virtual Effect CreateSkinnedEffect(GLTFMATERIAL srcMaterial)
{
var dstMaterial = new SkinnedEffect(Device);
dstMaterial.Name = srcMaterial.Name;
dstMaterial.Alpha = GetAlphaLevel(srcMaterial);
dstMaterial.DiffuseColor = GetDiffuseColor(srcMaterial);
dstMaterial.SpecularColor = GetSpecularColor(srcMaterial);
dstMaterial.SpecularPower = GetSpecularPower(srcMaterial);
dstMaterial.EmissiveColor = GeEmissiveColor(srcMaterial);
dstMaterial.Texture = UseDiffuseTexture(srcMaterial);
dstMaterial.WeightsPerVertex = 4;
dstMaterial.PreferPerPixelLighting = true;
// apparently, SkinnedEffect does not support disabling textures, so we set a white texture here.
if (dstMaterial.Texture == null)
{
dstMaterial.Texture = UseTexture(null, null); // creates a dummy white texture.
}
return(dstMaterial);
}
// Monogame's BasicEffect uses Phong's shading, while glTF uses PBR shading, so
// given monogame's limitations, we try to guess the most appropiate values
// to have a reasonably good looking renders.
protected override Effect CreateEffect(GLTFMATERIAL srcMaterial, bool isSkinned)
{
return(isSkinned ? CreateSkinnedEffect(srcMaterial) : CreateRigidEffect(srcMaterial));
}
