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7465bfa65e
OpenGl_Context now skips loading functions related to mapping buffer, which are required by OpenGL ES 3.0 specs but not provided by WebGL 2.0. Message_PrinterSystemLog does not use a broken emscripten_log() anymore, which corrupted UNICODE strings. WasmOcctView::initWindow() - callbacks now set using EMSCRIPTEN_EVENT_TARGET_WINDOW instead of 0 used by older Emscripten API. Mouse callbacks now track canvas element and use EmscriptenMouseEvent::targetX/targetY instead of ::canvasX/canvasY as the latter was broken. Added emscripten_set_main_loop() setup to shut up eglSwapInterval() error message. Fixed missing \0 at the end of string converted by toUtf8Array().
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): https://emscripten.org/
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:
- Install Emscripten SDK and activate minimal configuration (Python, Java and CLang) following emsdk documentation. Activate also MinGW when building sample on Windows host.
- Build (using emsdk) or download FreeType static library.
- 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.
- Perform building and installation steps.
> ${EMSDK}/fastcomp/emscripten/cmake/Modules/Platform/Emscripten.cmake
- Configure CMake for building this WebGL sample using emsdk with paths to OCCT and FreeType. Perform building and installation steps.
- Copy data/occ/Ball.brep from OCCT into "samples" folder within WebGL sample installation path.
- Navigate to installation folder and start web server from it; Python coming with emsdk can be used for this purpose:
> python -m SimpleHTTPServer 8080
- Open compatible browser and enter path taking into account your web server settings:
> http://localhost:8080/occt-webgl-sample.html