Try to init spdlog a bit earlier

src/gl/imgui_hud.cpp

@@ -75,6 +75,7 @@ void imgui_init()
     if (cfg_inited)
         return;
 
+    init_spdlog();
     parse_overlay_config(&params, getenv("MANGOHUD_CONFIG"));
     _params = &params;
 

src/overlay.cpp

@@ -4,6 +4,9 @@
 #include <thread>
 #include <condition_variable>
 #include <spdlog/spdlog.h>
+#include <spdlog/cfg/env.h>
+#include <spdlog/sinks/stdout_color_sinks.h>
+#include <spdlog/sinks/rotating_file_sink.h>
 #include <filesystem.h>
 #include <sys/stat.h>
 #include "overlay.h"
@@ -49,6 +52,31 @@ bool gpu_metrics_exists = false;
 bool steam_focused = false;
 vector<float> frametime_data(200,0.f);
 
+void init_spdlog()
+{
+   if (spdlog::get("MANGOHUD"))
+      return;
+
+   spdlog::set_default_logger(spdlog::stderr_color_mt("MANGOHUD")); // Just to get the name in log
+   if (getenv("MANGOHUD_USE_LOGFILE"))
+   {
+      try
+      {
+         // Not rotating when opening log as proton/wine create multiple (sub)processes
+         auto log = std::make_shared<spdlog::sinks::rotating_file_sink_mt> (get_config_dir() + "/MangoHud/MangoHud.log", 10*1024*1024, 5, false);
+         spdlog::get("MANGOHUD")->sinks().push_back(log);
+      }
+      catch (const spdlog::spdlog_ex &ex)
+      {
+         SPDLOG_ERROR("{}", ex.what());
+      }
+   }
+#ifndef NDEBUG
+   spdlog::set_level(spdlog::level::level_enum::debug);
+#endif
+   spdlog::cfg::load_env_levels();
+}
+
 void FpsLimiter(struct fps_limit& stats){
    stats.sleepTime = stats.targetFrameTime - (stats.frameStart - stats.frameEnd);
    if (stats.sleepTime > stats.frameOverhead) {
@@ -638,13 +666,11 @@ void init_gpu_stats(uint32_t& vendorID, uint32_t reported_deviceID, overlay_para
             }
          }
 
-         SPDLOG_DEBUG("using amdgpu path: {}", path);
-
          std::string gpu_metrics_path = path + "/device/gpu_metrics";
          if (file_exists(gpu_metrics_path)) {
             gpu_metrics_exists = true;
             metrics_path = gpu_metrics_path;
-            SPDLOG_DEBUG("Using gpu_metrics");
+            SPDLOG_DEBUG("Using gpu_metrics of {}", path);
          }
          path += "/device";
          if (!amdgpu.vram_total)
@@ -661,6 +687,8 @@ void init_gpu_stats(uint32_t& vendorID, uint32_t reported_deviceID, overlay_para
          if (!amdgpu.busy)
             continue;
 
+         SPDLOG_DEBUG("using amdgpu path: {}", path);
+
          path += "/hwmon/";
          auto dirs = ls(path.c_str(), "hwmon", LS_DIRS);
          for (auto& dir : dirs) {

src/overlay.h

@@ -154,6 +154,7 @@ extern overlay_params *_params;
 extern double min_frametime, max_frametime;
 extern bool steam_focused;
 
+void init_spdlog();
 void position_layer(struct swapchain_stats& data, struct overlay_params& params, ImVec2 window_size);
 void render_imgui(swapchain_stats& data, struct overlay_params& params, ImVec2& window_size, bool is_vulkan);
 void update_hud_info(struct swapchain_stats& sw_stats, struct overlay_params& params, uint32_t vendorID);

src/overlay_params.cpp

@@ -18,8 +18,6 @@
 #include <array>
 #include <functional>
 #include <spdlog/spdlog.h>
-#include <spdlog/cfg/env.h>
-#include <spdlog/sinks/stdout_color_sinks.h>
 
 #include "overlay_params.h"
 #include "overlay.h"
@@ -551,13 +549,6 @@ void
 parse_overlay_config(struct overlay_params *params,
                   const char *env)
 {
-   if (!spdlog::get("MANGOHUD"))
-      spdlog::set_default_logger(spdlog::stderr_color_mt("MANGOHUD")); // Just to get the name in log
-#ifndef NDEBUG
-   spdlog::set_level(spdlog::level::level_enum::debug);
-#endif
-   spdlog::cfg::load_env_levels();
-
    *params = {};
 
    /* Visible by default */

src/vulkan.cpp

@@ -1977,6 +1977,7 @@ static void *find_ptr(const char *name)
 extern "C" VK_LAYER_EXPORT VKAPI_ATTR PFN_vkVoidFunction VKAPI_CALL overlay_GetDeviceProcAddr(VkDevice dev,
                                                                              const char *funcName)
 {
+   init_spdlog();
    void *ptr = find_ptr(funcName);
    if (ptr) return reinterpret_cast<PFN_vkVoidFunction>(ptr);
 
@@ -1990,6 +1991,7 @@ extern "C" VK_LAYER_EXPORT VKAPI_ATTR PFN_vkVoidFunction VKAPI_CALL overlay_GetD
 extern "C" VK_LAYER_EXPORT VKAPI_ATTR PFN_vkVoidFunction VKAPI_CALL overlay_GetInstanceProcAddr(VkInstance instance,
                                                                                const char *funcName)
 {
+   init_spdlog();
    void *ptr = find_ptr(funcName);
    if (ptr) return reinterpret_cast<PFN_vkVoidFunction>(ptr);