get_uv_attribute.h

/*
 * Copyright 2025 Adobe. All rights reserved.
 * This file is licensed to you under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. You may obtain a copy
 * of the License at http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
 * OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
#pragma once
 
#include <lagrange/SurfaceMesh.h>
#include <lagrange/utils/Error.h>
#include <lagrange/utils/fmt/format.h>
#include <lagrange/uv_mesh.h>
#include <lagrange/views.h>
 
#include <string_view>
#include <tuple>
#include <type_traits>
 
namespace lagrange::internal {

enum class TypeMismatchPolicy {
    Assert, 
    Graceful, 
};

template <typename Scalar, typename Index, typename UVScalar = Scalar>
AttributeId get_uv_id(
    const SurfaceMesh<Scalar, Index>& mesh,
    std::string_view uv_attribute_name = "",
    UVMeshOptions::ElementTypes element_types = UVMeshOptions::ElementTypes::IndexedOrVertex,
    TypeMismatchPolicy type_mismatch = TypeMismatchPolicy::Assert);

template <typename Scalar, typename Index, typename UVScalar = Scalar>
std::tuple<ConstRowMatrixView<UVScalar>, ConstVectorView<Index>> get_uv_attribute(
    const SurfaceMesh<Scalar, Index>& mesh,
    std::string_view uv_attribute_name = "");

template <typename Scalar, typename Index, typename UVScalar = Scalar>
std::tuple<RowMatrixView<UVScalar>, VectorView<Index>> ref_uv_attribute(
    SurfaceMesh<Scalar, Index>& mesh,
    std::string_view uv_attribute_name = "");

template <typename T>
struct UVScalarTag
{
    using type = T;
};

template <typename Scalar, typename Index, typename F>
auto dispatch_uv_scalar_type(
    SurfaceMesh<Scalar, Index>& mesh,
    const UVMeshOptions& options,
    std::string_view caller,
    F&& visitor)
{
    using OtherScalar = std::conditional_t<std::is_same_v<Scalar, float>, double, float>;
    if (auto id = uv_attribute_id<Scalar, Index, Scalar>(mesh, options)) {
        return visitor(UVScalarTag<Scalar>{}, *id);
    }
    if (auto id = uv_attribute_id<Scalar, Index, OtherScalar>(mesh, options)) {
        return visitor(UVScalarTag<OtherScalar>{}, *id);
    }
    throw Error(format("{}: no suitable UV attribute found.", caller));
}
 
} // namespace lagrange::internal