Function ffi_thread_func

native/debug/test_multithread.cpp:26–70

--- THE FFI / WORKER THREAD --- This thread simulates your library receiving FFI calls and rendering them offscreen.

// This thread simulates your library receiving FFI calls and rendering them
// offscreen.
void ffi_thread_func() {
  // 1. Claim the background context for this thread
  SDL_GL_MakeCurrent(window, ffiContext);

  // 2. Create a thread-local NanoVG context
  NVGcontext* ffi_vg = nvgCreateGL3(NVG_ANTIALIAS | NVG_STENCIL_STROKES);

  float rotation = 0;

  while (running) {
    // In a real library, this is where you'd wait for FFI commands
    SDL_Delay(16);  // Aim for ~60fps updates

    // 3. Render into the shared framebuffer
    nvgluBindFramebuffer(uiLayer);
    glViewport(0, 0, 1024, 768);
    glClearColor(0, 0, 0, 0);  // Transparent base
    glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    nvgBeginFrame(ffi_vg, 1024, 768, 1.0f);

    // Rotating shape to prove the thread is alive
    rotation += 0.02f;
    nvgSave(ffi_vg);
    nvgTranslate(ffi_vg, 500, 350);
    nvgRotate(ffi_vg, rotation);
    nvgBeginPath(ffi_vg);
    nvgRect(ffi_vg, -50, -50, 100, 100);
    nvgStrokeColor(ffi_vg, nvgRGBA(255, 165, 0, 255));
    nvgStrokeWidth(ffi_vg, 10);
    nvgStroke(ffi_vg);
    nvgRestore(ffi_vg);

    nvgFontSize(ffi_vg, 24.0f);
    nvgFillColor(ffi_vg, nvgRGBA(255, 255, 255, 255));
    nvgTextAlign(ffi_vg, NVG_ALIGN_CENTER | NVG_ALIGN_MIDDLE);
    nvgText(ffi_vg, 500, 450, "RENDERED BY FFI THREAD", NULL);
    nvgEndFrame(ffi_vg);

    // 4. CRITICAL: Flush commands so Main Thread sees the data
    glFlush();
  }

  nvgDeleteGL3(ffi_vg);
}

// --- THE MAIN THREAD (CONSUMER) ---
int main(int argc, char* argv[]) {