Open CASCADE Technology

OCCT WebGL Viewer sample

This sample demonstrates simple way of using OCCT libraries in Web application written in C++ and translated into WebAssembly module using Emscripten SDK (emsdk):

Sample consists of the Open CASCADE 3D Viewer with a button for opening a model in BREP format. The sample requires a WebGL 2.0 capable browser supporting WebAssembly 1.0 (Wasm).

Installation and configuration:

  1. Install Emscripten SDK and activate minimal configuration (Python, Java and CLang) following emsdk documentation. Activate also MinGW when building sample on Windows host.
  2. Build (using emsdk) or download FreeType static library.
  3. Configure CMake for building Open CASCADE Technology (OCCT) static libraries (BUILD_LIBRARY_TYPE="Static"). For this, activate emsdk command prompt, configure CMake for building OCCT using cross-compilation toolchain, disable BUILD_MODULE_Draw.
  4. Perform building and installation steps.
    > ${EMSDK}/fastcomp/emscripten/cmake/Modules/Platform/Emscripten.cmake
  5. Configure CMake for building this WebGL sample using emsdk with paths to OCCT and FreeType. Perform building and installation steps.
  6. Copy data/occ/Ball.brep from OCCT into "samples" folder within WebGL sample installation path.
  7. Navigate to installation folder and start web server from it; Python coming with emsdk can be used for this purpose:
    > python -m SimpleHTTPServer 8080
  8. Open compatible browser and enter path taking into account your web server settings:
    > http://localhost:8080/occt-webgl-sample.html