From 7fb4c45046917e68bbfe8c2561ca6ef26465c4af Mon Sep 17 00:00:00 2001
From: SirMangler <thecatsmangler@gmail.com>
Date: Sun, 3 Jan 2021 19:00:32 +0000
Subject: [PATCH] FPS Counter and debug overlay CVAR

---
 Editor/ViewManager.cpp         |  3 +++
 Runtime/Graphics/CGraphics.cpp | 17 +++++++++++++++++
 Runtime/Graphics/CGraphics.hpp |  8 ++++++++
 3 files changed, 28 insertions(+)

diff --git a/Editor/ViewManager.cpp b/Editor/ViewManager.cpp
index 553b2a88e..fb2b6fc4b 100644
--- a/Editor/ViewManager.cpp
+++ b/Editor/ViewManager.cpp
@@ -66,6 +66,9 @@ void ViewManager::TestGameView::think() {
       if (m_cvarCommons.m_debugOverlayShowFrameCounter->toBoolean())
         overlayText += fmt::format(FMT_STRING("Frame: {}\n"), g_StateManager->GetUpdateFrameIndex());
 
+      if (m_cvarCommons.m_debugOverlayShowFramerate->toBoolean())
+          overlayText += fmt::format(FMT_STRING("FPS: {}\n"), urde::CGraphics::GetFPS());
+
       if (m_cvarCommons.m_debugOverlayShowInGameTime->toBoolean()) {
         double igt = g_GameState->GetTotalPlayTime();
         u32 ms = u64(igt * 1000) % 1000;
diff --git a/Runtime/Graphics/CGraphics.cpp b/Runtime/Graphics/CGraphics.cpp
index 48171d31c..18cdec78e 100644
--- a/Runtime/Graphics/CGraphics.cpp
+++ b/Runtime/Graphics/CGraphics.cpp
@@ -34,6 +34,9 @@ SViewport g_Viewport = {
     0, 0, 640, 480, 640 / 2.f, 480 / 2.f, 0.0f,
 };
 u32 CGraphics::g_FrameCounter = 0;
+u32 CGraphics::g_Framerate = 0;
+u32 CGraphics::g_FramesPast = 0;
+frame_clock::time_point CGraphics::g_FrameStartTime = frame_clock::now();
 
 const std::array<zeus::CMatrix3f, 6> CGraphics::skCubeBasisMats{{
     /* Right */
@@ -126,6 +129,8 @@ void CGraphics::EndScene() {
   CLineRenderer::UpdateBuffers();
 
   ++g_FrameCounter;
+
+  UpdateFPSCounter();
 }
 
 void CGraphics::SetAlphaCompare(ERglAlphaFunc comp0, u8 ref0, ERglAlphaOp op, ERglAlphaFunc comp1, u8 ref1) {}
@@ -444,6 +449,18 @@ void CGraphics::TickRenderTimings() {
   g_DefaultSeconds = g_RenderTimings / 60.f;
 }
 
+static constexpr u64 FPS_REFRESH_RATE = 1000; 
+void CGraphics::UpdateFPSCounter() {
+  ++g_FramesPast;
+
+  std::chrono::duration<double, std::milli> timeElapsed = frame_clock::now() - g_FrameStartTime;
+  if (timeElapsed.count() > FPS_REFRESH_RATE) {
+      g_Framerate = g_FramesPast;
+      g_FrameStartTime = frame_clock::now(); 
+      g_FramesPast = 0;
+  }
+}
+
 boo::IGraphicsDataFactory::Platform CGraphics::g_BooPlatform = boo::IGraphicsDataFactory::Platform::Null;
 boo::IGraphicsDataFactory* CGraphics::g_BooFactory = nullptr;
 boo::IGraphicsCommandQueue* CGraphics::g_BooMainCommandQueue = nullptr;
diff --git a/Runtime/Graphics/CGraphics.hpp b/Runtime/Graphics/CGraphics.hpp
index cf4eb982c..b85a51dce 100644
--- a/Runtime/Graphics/CGraphics.hpp
+++ b/Runtime/Graphics/CGraphics.hpp
@@ -2,6 +2,7 @@
 
 #include <array>
 #include <vector>
+#include <chrono>
 
 #include "Runtime/RetroTypes.hpp"
 
@@ -18,6 +19,8 @@
 #include <zeus/CVector2i.hpp>
 #include <zeus/CVector2f.hpp>
 
+using frame_clock = std::chrono::high_resolution_clock;
+
 namespace urde {
 extern hecl::CVar* g_disableLighting;
 class CLight;
@@ -309,7 +312,12 @@ public:
   static float GetSecondsMod900();
   static void TickRenderTimings();
   static u32 g_FrameCounter;
+  static u32 g_Framerate;
+  static u32 g_FramesPast;
+  static frame_clock::time_point g_FrameStartTime;
   static u32 GetFrameCounter() { return g_FrameCounter; }
+  static u32 GetFPS() { return g_Framerate; }
+  static void UpdateFPSCounter();
 
   static boo::IGraphicsDataFactory::Platform g_BooPlatform;
   static const boo::SystemChar* g_BooPlatformName;