public MeshPrimitiveAttributes BuildMeshAttributes(Dictionary <Buffer, byte[]> bufferCache)
{
var attributes = new MeshPrimitiveAttributes();
if (Attributes.ContainsKey(SemanticProperties.POSITION))
{
var accessor = Attributes[SemanticProperties.POSITION].Value;
var bufferData = bufferCache[accessor.BufferView.Value.Buffer.Value];
attributes.Vertices = accessor.AsVector3Array(bufferData);
}
if (Indices != null)
{
var accessor = Indices.Value;
var bufferData = bufferCache[accessor.BufferView.Value.Buffer.Value];
var unflippedTriangles = accessor.AsIntArray(bufferData);
var triangles = new int[unflippedTriangles.Length];
for (int i = 0; i < unflippedTriangles.Length; i += 3)
{
triangles[i + 2] = unflippedTriangles[i];
triangles[i + 1] = unflippedTriangles[i + 1];
triangles[i] = unflippedTriangles[i + 2];
}
attributes.Triangles = triangles;
}
else
{
var triangles = new int[attributes.Vertices.Length];
for (int i = 0; i < triangles.Length; i += 3)
{
triangles[i + 2] = i;
triangles[i + 1] = i + 1;
triangles[i] = i + 2;
}
attributes.Triangles = triangles;
}
if (Attributes.ContainsKey(SemanticProperties.NORMAL))
{
var accessor = Attributes[SemanticProperties.NORMAL].Value;
var bufferData = bufferCache[accessor.BufferView.Value.Buffer.Value];
attributes.Normals = accessor.AsVector3Array(bufferData);
}
if (Attributes.ContainsKey(SemanticProperties.TexCoord(0)))
{
var accessor = Attributes[SemanticProperties.TexCoord(0)].Value;
var bufferData = bufferCache[accessor.BufferView.Value.Buffer.Value];
attributes.Uv = accessor.AsVector2Array(bufferData);
}
if (Attributes.ContainsKey(SemanticProperties.TexCoord(1)))
{
var accessor = Attributes[SemanticProperties.TexCoord(1)].Value;
var bufferData = bufferCache[accessor.BufferView.Value.Buffer.Value];
attributes.Uv2 = accessor.AsVector2Array(bufferData);
}
if (Attributes.ContainsKey(SemanticProperties.TexCoord(2)))
{
var accessor = Attributes[SemanticProperties.TexCoord(2)].Value;
var bufferData = bufferCache[accessor.BufferView.Value.Buffer.Value];
attributes.Uv3 = accessor.AsVector2Array(bufferData);
}
if (Attributes.ContainsKey(SemanticProperties.TexCoord(3)))
{
var accessor = Attributes[SemanticProperties.TexCoord(3)].Value;
var bufferData = bufferCache[accessor.BufferView.Value.Buffer.Value];
attributes.Uv4 = accessor.AsVector2Array(bufferData);
}
if (Attributes.ContainsKey(SemanticProperties.Color(0)))
{
var accessor = Attributes[SemanticProperties.Color(0)].Value;
var bufferData = bufferCache[accessor.BufferView.Value.Buffer.Value];
attributes.Colors = accessor.AsColorArray(bufferData);
}
if (Attributes.ContainsKey(SemanticProperties.TANGENT))
{
var accessor = Attributes[SemanticProperties.TANGENT].Value;
var bufferData = bufferCache[accessor.BufferView.Value.Buffer.Value];
attributes.Tangents = accessor.AsVector4Array(bufferData);
}
return(attributes);
}
// Taken from: http://answers.unity3d.com/comments/190515/view.html
// Official support for Mesh.RecalculateTangents should be coming in 5.6
// https://feedback.unity3d.com/suggestions/recalculatetangents
private MeshPrimitiveAttributes CalculateAndSetTangents(MeshPrimitiveAttributes attributes)
{
var triangleCount = attributes.Triangles.Length;
var vertexCount = attributes.Vertices.Length;
var tan1 = new Vector3[vertexCount];
var tan2 = new Vector3[vertexCount];
attributes.Tangents = new Vector4[vertexCount];
for (long a = 0; a < triangleCount; a += 3)
{
long i1 = attributes.Triangles[a + 0];
long i2 = attributes.Triangles[a + 1];
long i3 = attributes.Triangles[a + 2];
var v1 = attributes.Vertices[i1];
var v2 = attributes.Vertices[i2];
var v3 = attributes.Vertices[i3];
var w1 = attributes.Uv[i1];
var w2 = attributes.Uv[i2];
var w3 = attributes.Uv[i3];
var x1 = v2.x - v1.x;
var x2 = v3.x - v1.x;
var y1 = v2.y - v1.y;
var y2 = v3.y - v1.y;
var z1 = v2.z - v1.z;
var z2 = v3.z - v1.z;
var s1 = w2.x - w1.x;
var s2 = w3.x - w1.x;
var t1 = w2.y - w1.y;
var t2 = w3.y - w1.y;
var r = 1.0f / (s1 * t2 - s2 * t1);
var sdir = new Vector3((t2 * x1 - t1 * x2) * r, (t2 * y1 - t1 * y2) * r, (t2 * z1 - t1 * z2) * r);
var tdir = new Vector3((s1 * x2 - s2 * x1) * r, (s1 * y2 - s2 * y1) * r, (s1 * z2 - s2 * z1) * r);
tan1[i1] += sdir;
tan1[i2] += sdir;
tan1[i3] += sdir;
tan2[i1] += tdir;
tan2[i2] += tdir;
tan2[i3] += tdir;
}
for (long a = 0; a < vertexCount; ++a)
{
var n = attributes.Normals[a];
var t = tan1[a];
Vector3.OrthoNormalize(ref n, ref t);
attributes.Tangents[a].x = t.x;
attributes.Tangents[a].y = t.y;
attributes.Tangents[a].z = t.z;
attributes.Tangents[a].w = (Vector3.Dot(Vector3.Cross(n, t), tan2[a]) < 0.0f) ? -1.0f : 1.0f;
}
return(attributes);
}