fix FBOs in dynamically loaded modules

(thanks, Cameron!)

src/widgets/FramebufferWidget.cpp

@@ -39,6 +39,20 @@ void FramebufferWidget::draw(NVGcontext *vg) {
    // printf("xxx FramebufferWidget::draw: global_ui=%p\n", global_ui);
 #ifdef RACK_PLUGIN_SHARED
    bool bFBO = global_ui->b_fbo_shared;
+
+   static bool bInit = false;
+   if(bFBO && !bInit)
+   {
+      printf("xxx FramebufferWidget::draw: lazy-init glew\n");
+      glewExperimental = GL_TRUE;
+      bInit = true;
+      if(glewInit() != GLEW_OK) {
+         printf("Could not init glew.\n");
+         return;
+      }
+      // GLEW generates GL error because it calls glGetString(GL_EXTENSIONS), we'll consume it here.
+      glGetError();
+   }
 #else
    bool bFBO = global_ui->b_fbo;
 #endif // RACK_PLUGIN_SHARED

vst2_bin/settings.json

@@ -14,7 +14,7 @@
   "refreshRate": 30,
   "vsync": true,
   "fbo": true,
-  "fbo_shared": false,
+  "fbo_shared": true,
   "touchInput": false,
   "touchKbd": false,
   "oversampleFactor": 1.0,