Fix #142876: Cycles crash with OSL and interactive updates

Update use_shading, use_camera and the shading system pointers in the same
location, so that when the render is interrupted they are in a consistent state.

The added null pointer checks are not strictly needed, but just in case it
goes out of sync for another reason.

Pull Request: https://projects.blender.org/blender/blender/pulls/143467

intern/cycles/kernel/osl/globals.cpp

@@ -23,9 +23,13 @@ OSLThreadData::OSLThreadData(OSLGlobals *osl_globals, const int thread_index)
   memset((void *)&shader_globals, 0, sizeof(shader_globals));
   shader_globals.tracedata = &tracedata;
 
-  osl_thread_info = ss->create_thread_info();
-  context = ss->get_context(osl_thread_info);
-  oiio_thread_info = globals->ts->get_perthread_info();
+  if (ss) {
+    osl_thread_info = ss->create_thread_info();
+    context = ss->get_context(osl_thread_info);
+  }
+  if (globals->ts) {
+    oiio_thread_info = globals->ts->get_perthread_info();
+  }
 }
 
 OSLThreadData::~OSLThreadData()

intern/cycles/scene/osl.cpp

@@ -173,6 +173,10 @@ void OSLManager::device_update_post(Device *device,
       ss->Shader(*group, "shader", scene->camera->script_name, "camera");
       ss->ShaderGroupEnd(*group);
 
+      og->ss = ss;
+      og->ts = get_texture_system();
+      og->services = static_cast<OSLRenderServices *>(ss->renderer());
+
       og->camera_state = group;
       og->use_camera = true;
 
@@ -275,11 +279,9 @@ void OSLManager::device_free(Device *device, DeviceScene * /*dscene*/, Scene *sc
   /* clear shader engine */
   foreach_osl_device(device, [](Device *, OSLGlobals *og) {
     og->use_shading = false;
+    og->use_camera = false;
     og->ss = nullptr;
     og->ts = nullptr;
-
-    og->use_shading = false;
-    og->use_camera = false;
     og->camera_state.reset();
   });
 
@@ -631,7 +633,12 @@ void OSLShaderManager::device_update_specific(Device *device,
   LOG_INFO << "Total " << scene->shaders.size() << " shaders.";
 
   /* setup shader engine */
-  OSLManager::foreach_osl_device(device, [](Device *, OSLGlobals *og) {
+  OSLManager::foreach_osl_device(device, [scene](Device *sub_device, OSLGlobals *og) {
+    OSL::ShadingSystem *ss = scene->osl_manager->get_shading_system(sub_device);
+    og->ss = ss;
+    og->ts = scene->osl_manager->get_texture_system();
+    og->services = static_cast<OSLRenderServices *>(ss->renderer());
+
     og->use_shading = true;
 
     og->surface_state.clear();

intern/cycles/scene/osl.h

@@ -80,6 +80,7 @@ class OSLManager {
   OSLShaderInfo *shader_loaded_info(const string &hash);
 
   OSL::ShadingSystem *get_shading_system(Device *sub_device);
+  OSL::TextureSystem *get_texture_system();
   static void foreach_osl_device(Device *device,
                                  const std::function<void(Device *, OSLGlobals *)> &callback);
 #endif
@@ -98,8 +99,6 @@ class OSLManager {
   void foreach_shading_system(const std::function<void(OSL::ShadingSystem *)> &callback);
   void foreach_render_services(const std::function<void(OSLRenderServices *)> &callback);
 
-  OSL::TextureSystem *get_texture_system();
-
   Device *device_;
   map<string, OSLShaderInfo> loaded_shaders;