dataSourceAttributeColorSpace.h

//
// Copyright 2023 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_USD_IMAGING_USD_IMAGING_DATA_SOURCE_ATTRIBUTE_COLORSPACE_H
#define PXR_USD_IMAGING_USD_IMAGING_DATA_SOURCE_ATTRIBUTE_COLORSPACE_H
 
#include "pxr/usd/usd/attribute.h"
#include "pxr/usdImaging/usdImaging/api.h"
#include "pxr/imaging/hd/dataSource.h"
#include "pxr/imaging/hd/dataSourceTypeDefs.h"
#include "pxr/usd/usd/colorSpaceAPI.h"
 
PXR_NAMESPACE_OPEN_SCOPE
 
class UsdImagingDataSourceAttributeColorSpace : public HdTokenDataSource
{
public:
 
    HD_DECLARE_DATASOURCE(UsdImagingDataSourceAttributeColorSpace);
 
    VtValue GetValue(HdSampledDataSource::Time shutterOffset) override
    {
        return VtValue(GetTypedValue(shutterOffset));
    }
 
    TfToken GetTypedValue(HdSampledDataSource::Time shutterOffset) override
    {
        if (!_usdAttr) {
            return {};
        }
 
        TF_UNUSED(shutterOffset);
 
        // Special Case handling of UsdUVTexture Nodes which has an
        // 'inputs:sourceColorSpace' that we want to consolidate on the 
        // 'inputs:file' parameter
        TfToken sourceColorSpaceInput = _GetSourceColorSpaceInput();
        if (!sourceColorSpaceInput.IsEmpty()) {
            return sourceColorSpaceInput;
        }
 
        // If there is no inputs:sourceColorSpace value authored, use the
        // ColorspaceAPI to find the resolved color space for the attribute.
        return UsdColorSpaceAPI::ComputeColorSpaceName(_usdAttr);
    }
 
    bool GetContributingSampleTimesForInterval(
        HdSampledDataSource::Time startTime,
        HdSampledDataSource::Time endTime,
        std::vector<HdSampledDataSource::Time> *outSampleTimes) override
    {
        TF_UNUSED(startTime);
        TF_UNUSED(endTime);
        return false;
    }
 
private:
 
    UsdImagingDataSourceAttributeColorSpace(const UsdAttribute &usdAttr);
 
 
    // Helper to get the TfToken authored to the 'inputs:sourceColorSpace' 
    // for the 'inputs:file' attribute
    TfToken _GetSourceColorSpaceInput() {
        static TfToken inputSourceColorSpace("inputs:sourceColorSpace");
 
        // Only add add the source color space to the file attribute
        if (_usdAttr.GetName() != "inputs:file") {
            return TfToken();
        }
 
        TfToken sourceColorSpace;
        UsdPrim prim = _usdAttr.GetPrim();
        if (prim.HasAttribute(inputSourceColorSpace)) {
            VtValue sourceCSValue;
            prim.GetAttribute(inputSourceColorSpace).Get(&sourceCSValue);
            if (sourceCSValue.IsHolding<TfToken>()) {
                sourceColorSpace = sourceCSValue.UncheckedGet<TfToken>();
            }
        }
        return sourceColorSpace;
    }
 
private:
    UsdAttribute _usdAttr;
};
 
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif // PXR_USD_IMAGING_USD_IMAGING_DATA_SOURCE_ATTRIBUTE_COLORSPACE_H