public static CVec3 Cross(CVec3 a, CVec3 b) => new CVec3
{
v = new float[]
{
a.v[1] * b.v[2] - a.v[2] * b.v[1],
a.v[2] * b.v[0] - a.v[0] * b.v[2],
a.v[0] * b.v[1] - a.v[1] * b.v[0]
}
};
public static float Dot(CVec3 a, CVec3 b) => a.v[0] * b.v[0] + a.v[1] * b.v[1] + a.v[2] * b.v[2];
public CSkeletalMesh(USkeletalMesh mesh)
{
OriginalMesh = mesh;
// convert bounds
BoundingSphere = new FSphere
{
R = mesh.Bounds.sphere_radius / 2
};
BoundingBox = new FBox
{
Min = mesh.Bounds.origin - mesh.Bounds.box_extend,
Max = mesh.Bounds.origin + mesh.Bounds.box_extend
};
// MeshScale, MeshOrigin, RotOrigin are removed in UE4
//!! NOTE: MeshScale is integrated into RefSkeleton.RefBonePose[0].Scale3D.
//!! Perhaps rotation/translation are integrated too!
MeshOrigin = new CVec3 {
v = new float[] { 0, 0, 0 }
};
RotOrigin = new FRotator {
pitch = 0, roll = 0, yaw = 0
};
MeshScale = new CVec3 {
v = new float[] { 1, 1, 1 }
};
// convert LODs
Lods = new CSkelMeshLod[mesh.LODModels.Length];
for (int i = 0; i < Lods.Length; i++)
{
var SrcLod = mesh.LODModels[i];
if (SrcLod.Indices.Indices16.Length == 0 && SrcLod.Indices.Indices32.Length == 0)
{
// No indicies in this lod
continue;
}
int NumTexCoords = SrcLod.NumTexCoords;
if (NumTexCoords > 8)
{
throw new FileLoadException($"SkeletalMesh has too many ({NumTexCoords}) UV sets");
}
CSkelMeshLod Lod = new CSkelMeshLod
{
NumTexCoords = NumTexCoords,
HasNormals = true,
HasTangents = true,
};
// get vertex count and determine vertex source
int VertexCount = SrcLod.VertexBufferGPUSkin.GetVertexCount();
bool bUseVerticesFromSections = false;
// if (VertexCount == 0 && SrcLod.Sections.Length > 0 && SrcLod.Sections[0].SoftVertices.Count > 0)
// above is used for editor assets, but there are no chunks for soft vertices
Lod.AllocateVerts(VertexCount);
int chunkIndex = -1;
int lastChunkVertex = -1;
int chunkVertexIndex = 0;
ushort[] BoneMap = null;
for (int j = 0; j < VertexCount; j++)
{
while (j >= lastChunkVertex) // this will fix any issues with empty chunks or sections
{
// UE4.13+ code: chunk information migrated to sections
FSkelMeshSection S = SrcLod.Sections[++chunkIndex];
lastChunkVertex = (int)(S.base_vertex_index + S.num_vertices);
BoneMap = S.bone_map;
chunkVertexIndex = 0;
}
// get vertex from GPU skin
FSkelMeshVertexBase V;
if (!SrcLod.VertexBufferGPUSkin.bUseFullPrecisionUVs)
{
FGPUVert4Half V0 = SrcLod.VertexBufferGPUSkin.VertsHalf[j];
FMeshUVHalf[] SrcUV = V0.UV;
V = new FSkelMeshVertexBase
{
Infs = V0.Infs,
Normal = V0.Normal,
Pos = V0.Pos
};
// UV: convert half -> float
Lod.Verts[j].UV = (FMeshUVFloat)SrcUV[0];
for (int TexCoordIndex = 1; TexCoordIndex < NumTexCoords; TexCoordIndex++)
{
Lod.ExtraUV[TexCoordIndex - 1][j] = (FMeshUVFloat)SrcUV[TexCoordIndex];
}
}
else
{
FGPUVert4Float V0 = SrcLod.VertexBufferGPUSkin.VertsFloat[j];
FMeshUVFloat[] SrcUV = V0.UV;
V = new FSkelMeshVertexBase
{
Infs = V0.Infs,
Normal = V0.Normal,
Pos = V0.Pos
};
// UV: convert half -> float
Lod.Verts[j].UV = SrcUV[0];
for (int TexCoordIndex = 1; TexCoordIndex < NumTexCoords; TexCoordIndex++)
{
Lod.ExtraUV[TexCoordIndex - 1][j] = SrcUV[TexCoordIndex];
}
}
Lod.Verts[j].Position = V.Pos;
Lod.Verts[j].UnpackNormals(V.Normal);
// convert influences
Lod.Verts[j].Bone = new short[4];
int k2 = 0;
uint PackedWeights = 0;
for (int k = 0; k < 4; k++)
{
int BoneIndex = V.Infs.bone_index[k];
byte BoneWeight = V.Infs.bone_weight[k];
if (BoneWeight == 0)
{
continue; // skip this influence (but do not stop the loop!)
}
PackedWeights |= (uint)(BoneWeight << (k2 * 8));
Lod.Verts[j].Bone[k2] = (short)BoneMap[BoneIndex];
k2++;
}
Lod.Verts[j].PackedWeights = PackedWeights;
if (k2 < 4)
{
Lod.Verts[j].Bone[k2] = -1; // mark end of list
}
}
// indices
Lod.Indices.Initialize(SrcLod.Indices.Indices16, SrcLod.Indices.Indices32);
// sections
Lod.Sections = new CMeshSection[SrcLod.Sections.Length];
FSkeletalMeshLODInfo Info = mesh.LODInfo[i];
for (int j = 0; j < SrcLod.Sections.Length; j++)
{
FSkelMeshSection S = SrcLod.Sections[j];
CMeshSection Dst = new CMeshSection();
// remap material for LOD
int MaterialIndex = S.material_index;
if (MaterialIndex >= 0 && MaterialIndex < Info.LODMaterialMap.Length)
{
MaterialIndex = Info.LODMaterialMap[MaterialIndex];
}
if (S.material_index < mesh.Materials.Length)
{
Dst.Material = new UUnrealMaterial();// mesh.Materials[MaterialIndex].Material;
}
// -> TODO: actually get the object from the pak
Dst.FirstIndex = (int)S.base_index;
Dst.NumFaces = (int)S.num_triangles;
Lod.Sections[j] = Dst;
}
Lods[i] = Lod;
}
// copy skeleton
int NumBones = mesh.RefSkeleton.ref_bone_info.Length;
RefSkeleton = new CSkelMeshBone[NumBones];
for (int i = 0; i < NumBones; i++)
{
FMeshBoneInfo B = mesh.RefSkeleton.ref_bone_info[i];
FTransform T = mesh.RefSkeleton.ref_bone_pose[i];
CSkelMeshBone Dst = new CSkelMeshBone
{
Name = B.name,
ParentIndex = B.parent_index,
Position = T.translation,
Orientation = T.rotation
};
// fix skeleton; all bones but 0
if (i >= 1)
{
Dst.Orientation.Conjugate();
}
RefSkeleton[i] = Dst;
}
Sockets = null; // dunno where this is set
FinalizeMesh();
}
public void VectorMA(float scale, CVec3 b)
{
v[0] += scale * b.v[0];
v[1] += scale * b.v[1];
v[2] += scale * b.v[2];
}
public void BuildNormals()
{
if (HasNormals)
{
return;
}
int i, j;
// Find vertices to share.
// We are using very simple algorithm here: to share all vertices with the same position
// independently on normals of faces which share this vertex.
CVec3[] tmpNorm = new CVec3[NumVerts]; // really will use Points.Num() items, which value is smaller than NumVerts
CVertexShare Share = new CVertexShare();
Share.Prepare(Verts, NumVerts, 48);
for (i = 0; i < NumVerts; i++)
{
CPackedNormal NullVec;
NullVec.Data = 0;
Share.AddVertex(Verts[i].Position, NullVec);
}
for (i = 0; i < Indices.Length / 3; i++)
{
CSkelMeshVertex[] V = new CSkelMeshVertex[3];
CVec3[] N = new CVec3[3];
for (j = 0; j < 3; j++)
{
int idx = (int)Indices[i * 3 + j]; // index in Verts[]
V[j] = Verts[idx];
N[j] = tmpNorm[Share.WedgeToVert[idx]]; // remap to shared verts
}
// compute edges
CVec3[] D = new CVec3[]
{
V[1].Position - V[0].Position,
V[2].Position - V[1].Position,
V[0].Position - V[2].Position
};
// compute face normal
CVec3 norm = CVec3.Cross(D[1], D[0]);
norm.Normalize();
// compute angles
for (j = 0; j < 3; j++)
{
D[j].Normalize();
}
float[] angle = new float[]
{
(float)Math.Acos(-CVec3.Dot(D[0], D[2])),
(float)Math.Acos(-CVec3.Dot(D[0], D[1])),
(float)Math.Acos(-CVec3.Dot(D[1], D[2]))
};
// add normals for triangle verts
for (j = 0; j < 3; j++)
{
N[j].VectorMA(angle[j], norm);
}
for (j = 0; j < 3; j++)
{
int idx = (int)Indices[i * 3 + j];
Verts[idx] = V[j];
tmpNorm[Share.WedgeToVert[idx]] = N[j];
}
}
// TODO: add "hard angle threshold" - do not share vertex between faces when angle between them
// is too large.
// normalize shared normals ...
for (i = 0; i < Share.Points.Count; i++)
{
tmpNorm[i].Normalize();
}
// ... then place ("unshare") normals to Verts
for (i = 0; i < NumVerts; i++)
{
Verts[i].Normal.Pack(tmpNorm[Share.WedgeToVert[i]]);
}
HasNormals = true;
}