From 8d229bbd1fba2147e9b0db8a4b0166484f4a5348 Mon Sep 17 00:00:00 2001
From: Louis Gombert <louis.gombert@kitware.com>
Date: Thu, 22 Aug 2024 12:21:27 +0000
Subject: [PATCH] WASM binding v1

---
 src/CMakeLists.txt             |   5 ++
 src/SMESH/SMESH_Mesh.hxx       |   1 -
 src/webassembly/Bindings.cxx   | 109 +++++++++++++++++++++++++++++++++
 src/webassembly/CMakeLists.txt |  39 ++++++++++++
 src/webassembly/app.html       |  55 +++++++++++++++++
 5 files changed, 208 insertions(+), 1 deletion(-)
 create mode 100644 src/webassembly/Bindings.cxx
 create mode 100644 src/webassembly/CMakeLists.txt
 create mode 100644 src/webassembly/app.html

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index f0d3aa105..e44c25c2f 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -64,10 +64,15 @@ IF(SALOME_BUILD_GUI)
   )
 ENDIF(SALOME_BUILD_GUI)
 
+IF (DEFINED EMSCRIPTEN)
+  SET(SUBDIRS_WASM webassembly)
+ENDIF()
+
 SET(SUBDIRS
   ${SUBDIRS_COMMON}
   ${SUBDIRS_CGNS}
   ${SUBDIRS_GUI}
+  ${SUBDIRS_WASM}
 )
 
 FOREACH(dir ${SUBDIRS})
diff --git a/src/SMESH/SMESH_Mesh.hxx b/src/SMESH/SMESH_Mesh.hxx
index 99817219e..b6b8cb4cf 100644
--- a/src/SMESH/SMESH_Mesh.hxx
+++ b/src/SMESH/SMESH_Mesh.hxx
@@ -186,7 +186,6 @@ class SMESH_EXPORT SMESH_Mesh
   SMESH_Mesh* FindMesh( int meshId ) const;
 
   SMESHDS_Mesh * GetMeshDS() { return _meshDS; }
-
   const SMESHDS_Mesh * GetMeshDS() const { return _meshDS; }
 
   SMESH_Gen *GetGen()        { return _gen; }
diff --git a/src/webassembly/Bindings.cxx b/src/webassembly/Bindings.cxx
new file mode 100644
index 000000000..6e20ea64d
--- /dev/null
+++ b/src/webassembly/Bindings.cxx
@@ -0,0 +1,109 @@
+#include "GEOMImpl_Gen.hxx"
+#include "SMESHDS_Mesh.hxx"
+#include "SMESH_ControlsDef.hxx"
+#include "SMESH_Gen.hxx"
+#include "SMESH_Mesh.hxx"
+#include "StdMeshers_Hexa_3D.hxx"
+#include "StdMeshers_NumberOfSegments.hxx"
+#include "StdMeshers_Quadrangle_2D.hxx"
+#include "StdMeshers_Regular_1D.hxx"
+
+#include <emscripten/bind.h>
+
+/**
+ * Compute the total volume of the mesh
+ */
+double getTotalVolume(SMESH::Controls::Volume &volControl, SMESH_Mesh *mesh) {
+  std::cout << "Getting total volume" << std::endl;
+  double vol = 0;
+  SMDS_Mesh* ds = static_cast<SMDS_Mesh*>(mesh->GetMeshDS());
+  std::cout << "DS has " << ds->NbElements() << " elements" << std::endl;
+  volControl.SetMesh(ds);
+  for (int elemID = 0; elemID <= ds->NbElements(); elemID++) {
+    vol += volControl.GetValue(elemID);
+  }
+  return vol;
+}
+
+const std::string addHypothesis(SMESH_Mesh &mesh, TopoDS_Shape &shape, int id) {
+  std::string e;
+  mesh.AddHypothesis(shape, id, &e);
+  return e;
+}
+
+bool compute(SMESH_Gen& gen, SMESH_Mesh* mesh, TopoDS_Shape& shape) {
+  return gen.Compute(*mesh, shape);
+}
+
+// Required wrapping because SMESH_Mesh::GetMeshDS has 2 overloads, one const
+// and one not const, so the reference cannot decide which one to choose
+// SMDS_Mesh *getMeshDS(SMESH_Mesh &mesh) {
+//   return static_cast<SMDS_Mesh *>(mesh.GetMeshDS());
+// }
+
+// void setMesh(SMESH::Controls::Volume &vol, SMDS_Mesh* mesh) {
+//   vol.SetMesh(mesh);
+// }
+
+EMSCRIPTEN_BINDINGS(smesh) {
+  // OCCT bindings
+  emscripten::class_<TopoDS_Shape>("CAS_Shape").constructor<>();
+
+  // GEOM Bindings
+  emscripten::class_<GEOMImpl_Gen>("GEOM_Gen")
+      .constructor<>()
+      .function("GetI3DPrimOperations", &GEOMImpl_Gen::GetI3DPrimOperations,
+                emscripten::allow_raw_pointers());
+
+  // CAS Pointer
+  emscripten::class_<Handle_GEOM_Object>("Handle_GEOM_Object")
+      .function("get", &Handle_GEOM_Object::get,
+                emscripten::allow_raw_pointers());
+
+  emscripten::class_<GEOM_Object>("GEOM_Object")
+      .function("GetValue", &GEOM_Object::GetValue);
+
+  emscripten::class_<GEOMImpl_I3DPrimOperations>("GEOM_PrimOperations")
+      .function("MakeBoxDXDYDZ", &GEOMImpl_I3DPrimOperations::MakeBoxDXDYDZ);
+
+  // SMESH Bindings
+  emscripten::class_<SMESH_Gen>("SMESH_Gen")
+      .constructor<>()
+      .function("CreateMesh", &SMESH_Gen::CreateMesh,
+                emscripten::allow_raw_pointers())
+      .function("Compute", &compute,
+                emscripten::allow_raw_pointers());
+
+  emscripten::class_<SMESHDS_Mesh>("SMESH_DS_Mesh")
+      .function("NbElements", &SMESHDS_Mesh::NbElements);
+  emscripten::class_<SMDS_Mesh>("SMESH_SMDS_Mesh");
+
+  emscripten::class_<SMESH_Hypothesis>("SMESH_Hypothesis")
+      .class_function("IsStatusFatal", &SMESH_Hypothesis::IsStatusFatal);
+
+  emscripten::class_<SMESH_Mesh>("SMESH_Mesh")
+      .function("ShapeToMesh", &SMESH_Mesh::ShapeToMesh)
+      .function("AddHypothesis", &addHypothesis,
+                emscripten::allow_raw_pointers());
+      // .function("GetMeshDS", &getMeshDS, emscripten::allow_raw_pointers());
+
+  // Meshers
+  emscripten::class_<StdMeshers_Regular_1D>("SMESH_Meshers_Regular_1D")
+      .constructor<int, SMESH_Gen *>();
+  emscripten::class_<StdMeshers_NumberOfSegments>(
+      "SMESH_Meshers_NumberOfSegments")
+      .constructor<int, SMESH_Gen *>()
+      .function("SetNumberOfSegments",
+                &StdMeshers_NumberOfSegments::SetNumberOfSegments);
+  emscripten::class_<StdMeshers_Quadrangle_2D>("SMESH_Meshers_Quadrangle_2D")
+      .constructor<int, SMESH_Gen *>();
+  emscripten::class_<StdMeshers_Hexa_3D>("SMESH_Meshers_Hexa_3D")
+      .constructor<int, SMESH_Gen *>();
+
+  // Measurements
+  emscripten::class_<SMESH::Controls::Volume>("SMESH_Controls_Volume")
+      .constructor<>()
+      // .function("SetMesh", &setMesh, emscripten::allow_raw_pointers())
+      // .function("GetValue", &SMESH::Controls::Volume::GetValue)
+      .function("GetTotal", &getTotalVolume, emscripten::allow_raw_pointers());
+}
diff --git a/src/webassembly/CMakeLists.txt b/src/webassembly/CMakeLists.txt
new file mode 100644
index 000000000..41d05230d
--- /dev/null
+++ b/src/webassembly/CMakeLists.txt
@@ -0,0 +1,39 @@
+add_executable(smeshjs Bindings.cxx)
+
+set_target_properties(smeshjs PROPERTIES
+  OUTPUT_NAME smesh
+)
+
+target_link_libraries(smeshjs PRIVATE SalomeIDLKernel GEOMImpl SMESHDS SMESHimpl StdMeshers SMESHEngine)
+target_include_directories(smeshjs PRIVATE
+  ${OpenCASCADE_INCLUDE_DIR}
+  ${KERNEL_INCLUDE_DIRS}
+  ${KERNEL_INCLUDE_DIRS}
+  ${MEDFILE_INCLUDE_DIRS}
+  ${MEDCOUPLING_INCLUDE_DIRS}
+  ${PROJECT_SOURCE_DIR}/src/Controls
+  ${PROJECT_SOURCE_DIR}/src/SMDS
+  ${PROJECT_SOURCE_DIR}/src/SMESH
+  ${PROJECT_SOURCE_DIR}/src/SMESHDS
+  ${PROJECT_SOURCE_DIR}/src/StdMeshers
+  ${PROJECT_SOURCE_DIR}/src/SMESHUtils
+)
+target_link_options(smeshjs PRIVATE
+  "$<IF:$<CONFIG:Release>,-Oz,-O0>"
+  "--bind"
+  "--closure 1"
+  "SHELL:-sEXPORT_NAME=smesh"
+  "SHELL:-sALLOW_MEMORY_GROWTH=1"
+  "SHELL:-sEMULATE_FUNCTION_POINTER_CASTS=0"
+  "SHELL:-sMODULARIZE=1"
+  "SHELL:-sWASM=1"
+  "SHELL:-sFORCE_FILESYSTEM"
+  "SHELL:-sEXPORTED_RUNTIME_METHODS=FS"
+  "SHELL:-sWASM_BIGINT"
+  "SHELL:-sNO_DISABLE_EXCEPTION_CATCHING"
+)
+
+configure_file(
+  "${CMAKE_CURRENT_SOURCE_DIR}/app.html"
+  "${CMAKE_BINARY_DIR}/src/webassembly/index.html"
+  COPYONLY)
diff --git a/src/webassembly/app.html b/src/webassembly/app.html
new file mode 100644
index 000000000..ed9366dbb
--- /dev/null
+++ b/src/webassembly/app.html
@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+<html class="theme-dark">
+
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>SMESH Web</title>
+  <style>
+  </style>
+</head>
+
+<body>
+  <section class="section">
+  </section>
+  <script type="text/javascript" src="smesh.js"></script>
+  <script type="text/javascript">
+
+    smesh()
+      .then((Module) => {
+        // Create a Geometric box of size 10^3
+        Module.geom = new Module.GEOM_Gen();
+        Module.prim = Module.geom.GetI3DPrimOperations();
+        Module.box = Module.prim.MakeBoxDXDYDZ(10.0, 10.0, 10.0);
+        Module.shape = Module.box.get().GetValue();
+
+        // Create a mesh for this shape
+        Module.smesh = new Module.SMESH_Gen();
+        Module.mesh = Module.smesh.CreateMesh(false);
+        Module.mesh.ShapeToMesh(Module.shape);
+
+        // Define hypothesis in 1D, 2D, 3D
+        Module.seg = new Module.SMESH_Meshers_Regular_1D(0, Module.smesh);
+        var err = Module.mesh.AddHypothesis(Module.shape, 0);
+
+        Module.segs = new Module.SMESH_Meshers_NumberOfSegments(1, Module.smesh);
+        Module.segs.SetNumberOfSegments(5);
+        err = Module.mesh.AddHypothesis(Module.shape, 1);
+
+        Module.segs = new Module.SMESH_Meshers_Quadrangle_2D(2, Module.smesh);
+        err = Module.mesh.AddHypothesis(Module.shape, 2);
+
+        Module.segs = new Module.SMESH_Meshers_Hexa_3D(3, Module.smesh);
+        err = Module.mesh.AddHypothesis(Module.shape, 3);
+
+        // Compute volume
+        Module.smesh.Compute(Module.mesh, Module.shape);
+        Module.volume = new Module.SMESH_Controls_Volume();
+        const vol = Module.volume.GetTotal(Module.mesh);
+        console.log(`Volume is ${vol}`);
+      })
+      .catch(error => console.error("Internal exception: " + error));
+  </script>
+</body>
+
+</html>