1 files changed, 46 insertions, 0 deletions
diff --git a/source/blender/geometry/GEO_reverse_uv_sampler.hh b/source/blender/geometry/GEO_reverse_uv_sampler.hh
new file mode 100644
index 00000000000..ee91e0b0731
--- /dev/null
+++ b/source/blender/geometry/GEO_reverse_uv_sampler.hh
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+#include <optional>
+
+#include "BLI_math_vector.hh"
+#include "BLI_multi_value_map.hh"
+#include "BLI_span.hh"
+
+#include "DNA_meshdata_types.h"
+
+namespace blender::geometry {
+
+/**
+ * Can find the polygon/triangle that maps to a specific uv coordinate.
+ *
+ * \note this uses a trivial implementation currently that has to be replaced.
+ */
+class ReverseUVSampler {
+ private:
+  const Span<float2> uv_map_;
+  const Span<MLoopTri> looptris_;
+  int resolution_;
+  MultiValueMap<int2, int> looptris_by_cell_;
+
+ public:
+  ReverseUVSampler(const Span<float2> uv_map, const Span<MLoopTri> looptris);
+
+  enum class ResultType {
+    None,
+    Ok,
+    Multiple,
+  };
+
+  struct Result {
+    ResultType type = ResultType::None;
+    const MLoopTri *looptri = nullptr;
+    float3 bary_weights;
+  };
+
+  Result sample(const float2 &query_uv) const;
+  void sample_many(Span<float2> query_uvs, MutableSpan<Result> r_results) const;
+};
+
+}  // namespace blender::geometry