From 69f6788f9fbe42c282bdd3125dc622918c717847 Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <mclaughc@outlook.com>
Date: Fri, 27 Sep 2019 21:16:06 +1000
Subject: [PATCH] GPU: Show stats from previous frame if no rendering occured

---
 src/pse-sdl/sdl_interface.cpp |  2 +-
 src/pse/gpu_hw_opengl.cpp     | 27 +++++++++++++++++++--------
 src/pse/gpu_hw_opengl.h       |  1 +
 3 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/src/pse-sdl/sdl_interface.cpp b/src/pse-sdl/sdl_interface.cpp
index 46cd9439e..78112595c 100644
--- a/src/pse-sdl/sdl_interface.cpp
+++ b/src/pse-sdl/sdl_interface.cpp
@@ -548,7 +548,7 @@ void SDLInterface::Run()
     {
       m_fps_counter++;
       const double time = m_fps_timer.GetTimeSeconds();
-      if (time > 0.1)
+      if (time >= 0.25f)
       {
         m_fps = static_cast<float>(m_fps_counter / time);
         m_fps_counter = 0;
diff --git a/src/pse/gpu_hw_opengl.cpp b/src/pse/gpu_hw_opengl.cpp
index f077a7c22..45a98d52a 100644
--- a/src/pse/gpu_hw_opengl.cpp
+++ b/src/pse/gpu_hw_opengl.cpp
@@ -37,33 +37,44 @@ void GPU_HW_OpenGL::RenderUI()
 {
   GPU_HW::RenderUI();
 
+  ImGui::SetNextWindowSize(ImVec2(300.0f, 100.0f), ImGuiCond_Once);
+
+  const bool is_null_frame = m_stats.num_batches == 0;
+  if (!is_null_frame)
+  {
+    m_last_stats = m_stats;
+    m_stats = {};
+  }
+
   if (ImGui::Begin("GL Render Statistics"))
   {
     ImGui::Columns(2);
+    ImGui::SetColumnWidth(0, 200.0f);
 
-    ImGui::TextUnformatted("Texture Page Updates:");
+    ImGui::TextUnformatted("VRAM Read Texture Updates:");
     ImGui::NextColumn();
-    ImGui::Text("%u", m_stats.num_vram_read_texture_updates);
+    ImGui::Text("%u", m_last_stats.num_vram_read_texture_updates);
     ImGui::NextColumn();
 
     ImGui::TextUnformatted("Batches Drawn:");
     ImGui::NextColumn();
-    ImGui::Text("%u", m_stats.num_batches);
+    ImGui::Text("%u", m_last_stats.num_batches);
     ImGui::NextColumn();
 
     ImGui::TextUnformatted("Vertices Drawn: ");
     ImGui::NextColumn();
-    ImGui::Text("%u", m_stats.num_vertices);
+    ImGui::Text("%u", m_last_stats.num_vertices);
+    ImGui::NextColumn();
+
+    ImGui::TextUnformatted("GPU Active In This Frame: ");
+    ImGui::NextColumn();
+    ImGui::Text("%s", is_null_frame ? "Yes" : "No");
     ImGui::NextColumn();
 
     ImGui::Columns(1);
   }
 
   ImGui::End();
-
-  // skip update when no batches were drawn in that frame.. for now
-  if (m_stats.num_batches > 0)
-    m_stats = {};
 }
 
 void GPU_HW_OpenGL::InvalidateVRAMReadCache()
diff --git a/src/pse/gpu_hw_opengl.h b/src/pse/gpu_hw_opengl.h
index cc2776136..114c1010f 100644
--- a/src/pse/gpu_hw_opengl.h
+++ b/src/pse/gpu_hw_opengl.h
@@ -66,4 +66,5 @@ private:
   std::array<GL::Program, 3> m_texture_page_programs;
 
   GLStats m_stats = {};
+  GLStats m_last_stats = {};
 };