check float texture extension, use float32 or float16 if available, show extension on title bar, add thread and render task for lightmap rendering

src/app_layout.cpp

@@ -1237,6 +1237,23 @@ void App::initLayout()
             x->m_color = ShaderManager::ext_framebuffer_fetch ? glm::vec4(0, 1, 0, 1) : glm::vec4(1, 0, 0, 1);
         }
 
+        if (auto x = layout[main_id]->find<NodeBorder>("ext-flt"))
+        {
+            if (ShaderManager::ext_texture_float || ShaderManager::ext_half_float_pixel)
+            {
+                if (auto t = x->find<NodeText>("ext-flt-text"))
+                {
+                    int bits = ShaderManager::ext_texture_float ? 32 : 16;
+                    t->set_text_format("flt%d", bits);
+                }
+                x->m_color = glm::vec4(0, 1, 0, 1);
+            }
+            else
+            {
+                x->m_color = glm::vec4(1, 0, 0, 1);
+            }
+        }
+
         brush_update();
         
         // hacky thing to make the toolbar buttons not steal events when moving cursor fast