From 48c2e464cbba827abfff8ce081e0634cdb98cb43 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20M=C3=B6bius?= <moebius@cs.rwth-aachen.de>
Date: Tue, 1 Jun 2021 12:47:22 +0200
Subject: [PATCH] PLY writer: Added option to choose if we want to write
 texture coordinates as uv or ply (Thanks to Ossi Saukko for the patch)

---
 Doc/changelog.docu                       | 1 +
 src/OpenMesh/Core/IO/Options.hh          | 4 +++-
 src/OpenMesh/Core/IO/writer/PLYWriter.cc | 9 +++++++--
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/Doc/changelog.docu b/Doc/changelog.docu
index 1b5e0bf2..9a9e8ebb 100644
--- a/Doc/changelog.docu
+++ b/Doc/changelog.docu
@@ -33,6 +33,7 @@
 <li>OM Writer: Removed debug output</li>
 <li>OM Writer/Reader: Added support for (re)storing properties of type vector<T></li>
 <li>OM Reader: Properties can now be restored from files without the need to create the properties beforehand. Custom types need to be registered for this to work using the OM_REGISTER_PROPERTY_TYPE macro.</li>
+<li>PLY writer: Added option to choose if we want to write texture coordinates as uv or ply</li>
 </ul>
 
 <b>Tools</b>
diff --git a/src/OpenMesh/Core/IO/Options.hh b/src/OpenMesh/Core/IO/Options.hh
index 2e642180..347098af 100644
--- a/src/OpenMesh/Core/IO/Options.hh
+++ b/src/OpenMesh/Core/IO/Options.hh
@@ -111,7 +111,8 @@ public:
       ColorAlpha     = 0x0800, ///< Has (r) / store (w) alpha values for colors
       ColorFloat     = 0x1000, ///< Has (r) / store (w) float values for colors (currently only implemented for PLY and OFF files)
       Custom         = 0x2000, ///< Has (r)             custom properties (currently only implemented in PLY Reader ASCII version)
-      Status         = 0x4000  ///< Has (r) / store (w) status properties
+      Status         = 0x4000, ///< Has (r) / store (w) status properties
+      TexCoordST     = 0x8000  ///< Write texture coordinates as ST instead of UV
   };
 
 public:
@@ -212,6 +213,7 @@ public:
   bool face_has_status()     const { return check(Status); }
   bool color_has_alpha()     const { return check(ColorAlpha); }
   bool color_is_float()      const { return check(ColorFloat); }
+  bool use_st_coordinates()  const { return check(TexCoordST); }
 
 
   /// Returns true if _rhs has the same options enabled.
diff --git a/src/OpenMesh/Core/IO/writer/PLYWriter.cc b/src/OpenMesh/Core/IO/writer/PLYWriter.cc
index 49db3ec6..dc9e864a 100644
--- a/src/OpenMesh/Core/IO/writer/PLYWriter.cc
+++ b/src/OpenMesh/Core/IO/writer/PLYWriter.cc
@@ -278,8 +278,13 @@ void _PLYWriter_::write_header(std::ostream& _out, BaseExporter& _be, Options& _
   }
 
   if ( _opt.vertex_has_texcoord() ){
-    _out << "property float u" << '\n';
-    _out << "property float v" << '\n';
+    if ( _opt.use_st_coordinates() ){
+      _out << "property float s" << '\n';
+      _out << "property float t" << '\n';
+    } else {
+      _out << "property float u" << '\n';
+      _out << "property float v" << '\n';
+    }
   }
 
   if ( _opt.vertex_has_color() ){