1 files changed, 32 insertions, 0 deletions
diff --git a/source/blender/geometry/intern/reverse_uv_sampler.cc b/source/blender/geometry/intern/reverse_uv_sampler.cc
new file mode 100644
index 00000000000..9aa98895a86
--- /dev/null
+++ b/source/blender/geometry/intern/reverse_uv_sampler.cc
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "GEO_reverse_uv_sampler.hh"
+
+#include "BLI_math_geom.h"
+
+namespace blender::geometry {
+
+ReverseUVSampler::ReverseUVSampler(const Span<float2> uv_map, const Span<MLoopTri> looptris)
+    : uv_map_(uv_map), looptris_(looptris)
+{
+}
+
+ReverseUVSampler::Result ReverseUVSampler::sample(const float2 &query_uv) const
+{
+  for (const MLoopTri &looptri : looptris_) {
+    const float2 &uv0 = uv_map_[looptri.tri[0]];
+    const float2 &uv1 = uv_map_[looptri.tri[1]];
+    const float2 &uv2 = uv_map_[looptri.tri[2]];
+    float3 bary_weights;
+    if (!barycentric_coords_v2(uv0, uv1, uv2, query_uv, bary_weights)) {
+      continue;
+    }
+    if (IN_RANGE_INCL(bary_weights.x, 0.0f, 1.0f) && IN_RANGE_INCL(bary_weights.y, 0.0f, 1.0f) &&
+        IN_RANGE_INCL(bary_weights.z, 0.0f, 1.0f)) {
+      return Result{ResultType::Ok, &looptri, bary_weights};
+    }
+  }
+  return Result{};
+}
+
+}  // namespace blender::geometry