// ------------------------------------------------------------------------------------------ //
// Helper functions.
// ------------------------------------------------------------------------------------------ //
/// <summary>
/// Reads the material associated with the geometry at the target path. If a valid material is
/// bound, the "surface" shader is inspected, if valid, the shader ID is queried and returned
/// via the shaderId output parameter. Returns true when shaderId is set.
/// </summary>
static public bool ReadMaterial(Scene scene,
string geometryPath,
MaterialSample materialSample,
out string shaderId)
{
// Discover the material bound to the geometry.
// Note that with this structure, the geometry type does not matter.
var geomMaterialBinding = new MaterialBindingSample();
// Discover the binding for the geometry.
// Note that the details of how to import geometry is handled in a different example.
scene.Read(geometryPath, geomMaterialBinding);
// In general, there is no guarantee that any prim is bound, so this null check is always
// required.
if (geomMaterialBinding.binding.targetPaths == null)
{
// In this example, exceptions are thrown on invalid data, but in practice invalid bindings
// should probably be collected into a summary report and emitted as a single warning.
throw new System.Exception("Expected bound material");
}
// Similarly, there is no guarantee the source file is well formed, so an invalid number of
// target paths must also be handled.
if (geomMaterialBinding.binding.targetPaths.Length != 1)
{
throw new System.Exception("Expected exactly one target path for material binding");
}
// Read the material, which will provide the shader binding.
scene.Read(geomMaterialBinding.binding.targetPaths[0], materialSample);
// Again, the surface may be invalid, so protect against broken scene description.
if (materialSample.surface == null || string.IsNullOrEmpty(materialSample.surface.connectedPath))
{
throw new System.Exception("Material had no surface bound");
}
string shaderPath = materialSample.surface.connectedPath.Replace(".outputs:out", "");
var prim = scene.Stage.GetPrimAtPath(new pxr.SdfPath(shaderPath));
if (prim == null || !prim.IsValid())
{
throw new System.Exception("Invalid shader prim");
}
var val = new VtValue();
if (!prim.GetAttributeValue(new TfToken("info:id"), val, scene.Time ?? UsdTimeCode.Default()))
{
throw new System.Exception("Shader prim had no identifier");
}
shaderId = pxr.UsdCs.VtValueToTfToken(val).ToString();
return(true);
}
/// <summary>
/// Serializes the attribute value to USD-ASCII and writes it to Debug.Log.
/// </summary>
void DebugPrintAttr(Scene srcScene, UsdAttribute attr, UsdTimeCode time)
{
// Copy the desired attribute into a temp scene, with nothing other than this one attr.
var tmpScene = Scene.Create();
// Up-Axis is unrelated to the attribute, but it makes the generated USDA look more correct,
// since it will include an up-axis.
tmpScene.UpAxis = srcScene.UpAxis;
// Define the owning prim for the attribute.
var tmpPrim = tmpScene.Stage.DefinePrim(attr.GetPath().GetPrimPath(), attr.GetPrim().GetTypeName());
// Define the attribute itself.
var tmpAttr = tmpPrim.CreateAttribute(attr.GetName(), attr.GetTypeName());
// Gather the default value and the value at the current time.
var defaultVal = attr.Get(UsdTimeCode.Default());
var valAtTime = attr.Get(time);
// Copy them to the new attribute.
if (!defaultVal.IsEmpty())
{
tmpAttr.Set(defaultVal);
}
if (attr.ValueMightBeTimeVarying())
{
tmpAttr.Set(valAtTime, time);
}
// If this is an array, get the size.
var arraySize = -1;
if (valAtTime.IsArrayValued())
{
arraySize = (int)valAtTime.GetArraySize();
}
// Metadata cannot be time-varying.
UsdMetadataValueMap metaData = attr.GetAllMetadata();
foreach (var key in metaData.GetKeys())
{
tmpAttr.SetMetadata(key, metaData.GetValue(key));
}
// Export the single attribute to a string.
var stringified = "";
tmpScene.Stage.ExportToString(out stringified, addSourceFileComment: false);
// Dispose the tmp scene.
tmpScene.Close();
tmpScene = null;
// Print.
if (arraySize > -1)
{
stringified = "Array Size: " + arraySize + "\n" + stringified;
}
Debug.Log("Path: <" + attr.GetPath().ToString() + ">\n" + stringified);
}