public static void Validate(this IG3D g3d)
{
// Check that no attributes are null
var n = g3d.Attributes.Count(attr => attr == null);
if (n > 0)
{
throw new Exception("Attributes cannot be null");
}
// Assure that there are no duplicates
g3d.Attributes.ToDictionary();
// Validate the descriptors
foreach (var attr in g3d.Attributes)
{
attr.Descriptor.Validate();
}
// Compute the number of faces
var faceCount = g3d.FaceCount();
// Assure that there is a vertex attribute
if (g3d.VertexAttribute.Descriptor.Association != Association.assoc_vertex)
{
throw new Exception("Vertex buffer is not associated with vertex: " + g3d.VertexAttribute.Descriptor);
}
if (g3d.VertexAttribute.Descriptor.DataArity != 3)
{
throw new Exception("Vertices should have an arity of 3");
}
if (g3d.Attributes(AttributeType.attr_vertex).Count() > 1)
{
throw new Exception("There can only be one vertex data set");
}
// Compute the number of vertices
var vertexCount = g3d.VertexCount();
// Computes the number of corners
var cornerCount = g3d.CornerVertexIndices().Count;
// Compute the number of groups. Groups requires the precense of a GroupIndex attribute
var groupCount = g3d.GroupIndexAttributes().FirstOrDefault()?.Count ?? -1;
// Compute the number of instance. The first instance channel determines the number of instances
var instanceCount = g3d.Attributes(Association.assoc_instance).FirstOrDefault()?.Count ?? -1;
// Check the number of items in each attribute
foreach (var attr in g3d.Attributes)
{
switch (attr.Descriptor.Association)
{
case Association.assoc_vertex:
if (attr.Count != vertexCount)
{
throw new Exception($"Attribute {attr.Descriptor} has {attr.Count} items, expected {vertexCount}");
}
break;
case Association.assoc_face:
if (attr.Count != faceCount)
{
throw new Exception($"Attribute {attr.Descriptor} has {attr.Count} items, expected {faceCount}");
}
break;
case Association.assoc_corner:
if (attr.Count != cornerCount)
{
throw new Exception($"Attribute {attr.Descriptor} has {attr.Count} items, expected {cornerCount}");
}
break;
case Association.assoc_edge:
if (attr.Count != cornerCount)
{
throw new Exception($"Attribute {attr.Descriptor} has {attr.Count} items, expected {cornerCount}");
}
break;
case Association.assoc_object:
if (attr.Count != 1)
{
throw new Exception($"Attribute {attr.Descriptor} has {attr.Count} items, expected 1");
}
break;
case Association.assoc_group:
if (attr.Count != groupCount)
{
throw new Exception($"Attribute {attr.Descriptor} has {attr.Count} items, expected {groupCount}");
}
break;
case Association.assoc_instance:
if (attr.Count != instanceCount)
{
throw new Exception($"Attribute {attr.Descriptor} has {attr.Count} items, expected {instanceCount}");
}
break;
case Association.assoc_none:
break;
default:
throw new Exception($"Attribute {attr.Descriptor} has invalid association");
}
}
// The following rules are stricter than absolutely necessary, but respecting them
// will make coding geometry libraries easier to write on top of the thing.
g3d.Attributes(AttributeType.attr_binormal).ToList()
.ValidateDataType(DataType.dt_float32)
.ValidateArity(3)
.ValidateAssociation(Association.assoc_vertex);
g3d.Attributes(AttributeType.attr_tangent).ToList()
.ValidateDataType(DataType.dt_float32)
.ValidateArity(3)
.ValidateAssociation(Association.assoc_vertex);
g3d.Attributes(AttributeType.attr_normal).ToList()
.ValidateDataType(DataType.dt_float32)
.ValidateArity(3)
.ValidateAssociation(Association.assoc_face, Association.assoc_corner, Association.assoc_vertex);
g3d.Attributes(AttributeType.attr_color).ToList()
.ValidateArity(1, 3, 4)
.ValidateAssociation(Association.assoc_face, Association.assoc_corner, Association.assoc_vertex,
Association.assoc_object);
g3d.Attributes(AttributeType.attr_visibility).ToList()
.ValidateArity(1)
.ValidateDataType(DataType.dt_int8, DataType.dt_int32, DataType.dt_float32);
g3d.Attributes(AttributeType.attr_faceindex).ToList()
.ValidateArity(1)
.ValidateDataType(DataType.dt_int32)
.ValidateAssociation(Association.assoc_face)
.ValidateMaxOne();
g3d.Attributes(AttributeType.attr_facesize).ToList()
.ValidateArity(1)
.ValidateDataType(DataType.dt_int32)
.ValidateAssociation(Association.assoc_face, Association.assoc_object)
.ValidateMaxOne();
g3d.Attributes(AttributeType.attr_index).ToList()
.ValidateArity(1)
.ValidateDataType(DataType.dt_int32)
.ValidateAssociation(Association.assoc_corner)
.ValidateMaxOne();
g3d.Attributes(AttributeType.attr_uv).ToList()
.ValidateArity(2, 3)
.ValidateDataType(DataType.dt_float32)
.ValidateAssociation(Association.assoc_vertex, Association.assoc_corner);
g3d.Attributes(AttributeType.attr_invalid).ToList()
.ValidateNone();
g3d.Attributes(AttributeType.attr_index).ToList()
.ValidateArity(1)
.ValidateDataType(DataType.dt_int32)
.ValidateAssociation(Association.assoc_corner)
.ValidateMaxOne();
g3d.Attributes(AttributeType.attr_mapchannel_data).ToList()
.ValidateArity(3)
.ValidateDataType(DataType.dt_float32)
.ValidateAssociation(Association.assoc_none);
g3d.Attributes(AttributeType.attr_mapchannel_index).ToList()
.ValidateArity(1)
.ValidateDataType(DataType.dt_int32)
.ValidateAssociation(Association.assoc_corner);
g3d.Attributes(AttributeType.attr_materialid).ToList()
.ValidateArity(1)
.ValidateDataType(DataType.dt_int32)
.ValidateAssociation(Association.assoc_face);
g3d.Attributes(AttributeType.attr_pervertex).ToList()
.ValidateArity(1)
.ValidateDataType(DataType.dt_float32)
.ValidateAssociation(Association.assoc_vertex);
g3d.Attributes(AttributeType.attr_polygroup).ToList()
.ValidateArity(1)
.ValidateDataType(DataType.dt_int32)
.ValidateAssociation(Association.assoc_face);
g3d.Attributes(AttributeType.attr_smoothing).ToList()
.ValidateArity(1)
.ValidateDataType(DataType.dt_int32)
.ValidateAssociation(Association.assoc_face);
g3d.Attributes(AttributeType.attr_instance_transform).ToList()
.ValidateArity(16)
.ValidateDataType(DataType.dt_float32)
.ValidateAssociation(Association.assoc_instance);
g3d.Attributes(AttributeType.attr_vertex).ToList()
.ValidateArity(3)
.ValidateDataType(DataType.dt_float32, DataType.dt_float64)
.ValidateAssociation(Association.assoc_vertex)
.ValidateExactlyOne();
}
public static IArray <int> CornerVertexIndices(this IG3D g3d)
=> g3d.IndexAttribute == null
? g3d.VertexCount().Range()
: g3d.IndexAttribute.ToInts();