private (PrimitiveTopology, IEnumerable <int>) TransformPrimitive(MeshPrimitive primitive)
{
switch (primitive.DrawPrimitiveType)
{
case PrimitiveType.TRIANGLES:
return(PrimitiveTopology.TriangleList,
primitive.GetTriangleIndices().SelectMany(_ => new[] { _.Item1, _.Item2, _.Item3 }));
case PrimitiveType.TRIANGLE_STRIP:
return(PrimitiveTopology.TriangleList,
primitive.GetTriangleIndices().SelectMany(_ => new[] { _.Item1, _.Item2, _.Item3 }));
case PrimitiveType.TRIANGLE_FAN:
return(PrimitiveTopology.TriangleList,
primitive.GetTriangleIndices().SelectMany(_ => new[] { _.Item1, _.Item2, _.Item3 }));
case PrimitiveType.POINTS:
return(PrimitiveTopology.PointList, primitive.GetPointIndices());
case PrimitiveType.LINES:
return(PrimitiveTopology.LineList,
primitive.GetLineIndices().SelectMany(_ => new[] { _.Item1, _.Item2 }));
case PrimitiveType.LINE_STRIP:
return(PrimitiveTopology.LineList,
primitive.GetLineIndices().SelectMany(_ => new[] { _.Item1, _.Item2 }));
case PrimitiveType.LINE_LOOP:
return(PrimitiveTopology.LineList,
primitive.GetLineIndices().SelectMany(_ => new[] { _.Item1, _.Item2 }));
default:
throw new ArgumentOutOfRangeException();
}
}
public MeshPrimitiveReader(MeshPrimitive srcPrim, bool doubleSided, MeshNormalsFallback fallbackNormals)
{
_Positions = srcPrim.GetVertexAccessor("POSITION")?.AsVector3Array();
_Normals = srcPrim.GetVertexAccessor("NORMAL")?.AsVector3Array();
if (_Normals == null)
{
_Normals = new XYZ[_Positions.Count];
for (int i = 0; i < _Normals.Count; ++i)
{
_Normals[i] = fallbackNormals.GetNormal(_Positions[i]);
}
}
_Color0 = srcPrim.GetVertexAccessor("COLOR_0")?.AsColorArray();
_TexCoord0 = srcPrim.GetVertexAccessor("TEXCOORD_0")?.AsVector2Array();
_Joints0 = srcPrim.GetVertexAccessor("JOINTS_0")?.AsVector4Array();
_Joints1 = srcPrim.GetVertexAccessor("JOINTS_1")?.AsVector4Array();
_Weights0 = srcPrim.GetVertexAccessor("WEIGHTS_0")?.AsVector4Array();
_Weights1 = srcPrim.GetVertexAccessor("WEIGHTS_1")?.AsVector4Array();
if (_Joints0 == null || _Weights0 == null)
{
_Joints0 = _Joints1 = _Weights0 = _Weights1 = null;
}
if (_Joints1 == null || _Weights1 == null)
{
_Joints1 = _Weights1 = null;
}
if (_Weights0 != null)
{
_Weights0 = _Weights0.ToArray(); // isolate memory to prevent overwriting source glTF.
for (int i = 0; i < _Weights0.Count; ++i)
{
var r = XYZW.Dot(_Weights0[i], XYZW.One);
_Weights0[i] /= r;
}
}
if (doubleSided) // Monogame's effect material does not support double sided materials, so we simulate it by adding reverse faces
{
var front = srcPrim.GetTriangleIndices();
var back = front.Select(item => (item.A, item.C, item.B));
_Triangles = front.Concat(back).ToArray();
}
else
{
_Triangles = srcPrim.GetTriangleIndices().ToArray();
}
}
