From 77a6a0a51068ee6c8156ebd02194026b8a197f50 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Till=20W=C3=BCbbers?= <till.wuebbers@gmail.com>
Date: Sat, 29 Mar 2025 05:37:07 +0100
Subject: [PATCH] fps display

---
 src/game/Setup.cpp |  3 ++-
 src/game/Tools.cpp | 35 ++++++++++++++++++++++++++++++++++-
 src/game/Tools.h   |  1 +
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/src/game/Setup.cpp b/src/game/Setup.cpp
index 1e8d30e..7299960 100644
--- a/src/game/Setup.cpp
+++ b/src/game/Setup.cpp
@@ -1,8 +1,8 @@
 #include "Global.h"
-#include "Input.h"
 #include "Instance.h"
 #include "Log.h"
 #include "Setup.h"
+#include "Tools.h"
 #include "rendering/Rendering.h"
 
 #include "bx/bx.h"
@@ -87,6 +87,7 @@ namespace Game
             bx::memCopy(win.LastHeldScanCodes, win.HeldScanCodes, sizeof(win.HeldScanCodes));
             bx::memCopy(win.LastHeldMouseButtons, win.HeldMouseButtons, sizeof(win.HeldMouseButtons));
         }
+        Tools::MeasureFrameEnd();
         FrameMark;
     }
 
diff --git a/src/game/Tools.cpp b/src/game/Tools.cpp
index 919a2a8..091687b 100644
--- a/src/game/Tools.cpp
+++ b/src/game/Tools.cpp
@@ -1,10 +1,18 @@
 #include "Instance.h"
 #include "Mesh.h"
 #include "Tools.h"
+#include "bx/timer.h"
 
 #include <imgui.h>
 #include <tracy/Tracy.hpp>
 
+namespace
+{
+    constexpr int32_t FrameTimeBufSize = 512;
+    int64_t FrameTimes[FrameTimeBufSize]{0};
+    int32_t FrameTimeIdx = 0;
+} // namespace
+
 namespace Tools
 {
     const char* GetAssetPath(Generated::AssetHandle assetHandle)
@@ -337,10 +345,35 @@ namespace Tools
             {
                 auto& drawList = *ImGui::GetWindowDrawList();
                 ImVec2 pos = ImGui::GetWindowPos();
-                drawList.AddRectFilled(pos, {pos.x + FpsPlotSize.x, pos.y + FpsPlotSize.y}, 0xFFFFFF33);
+                drawList.AddRectFilled(pos, {pos.x + FpsPlotSize.x, pos.y + FpsPlotSize.y}, 0x22222233);
+
+                float scale = 1000.0f;
+
+                for (int32_t i = 0; i < FrameTimeBufSize; ++i)
+                {
+                    int32_t idx = FrameTimeIdx - i - 1;
+                    int32_t prevIdx = idx - 1;
+                    if (idx < 0) idx += FrameTimeBufSize;
+                    if (prevIdx < 0) prevIdx += FrameTimeBufSize;
+
+                    if (FrameTimes[idx] == 0 || FrameTimes[prevIdx] == 0) continue;
+
+                    int64_t frameTime = FrameTimes[idx] - FrameTimes[prevIdx];
+                    double frameTimeSec = (double)frameTime / bx::getHPFrequency();
+                    drawList.AddLine(
+                        {pos.x + (FpsPlotSize.x - i - 1), pos.y + FpsPlotSize.y},
+                        {pos.x + (FpsPlotSize.x - i - 1), pos.y + FpsPlotSize.y - (float)frameTimeSec * scale},
+                        0xFFFFFFFF);
+                }
             }
             ImGui::EndChild();
         }
         ImGui::End();
     }
+    void MeasureFrameEnd()
+    {
+        FrameTimes[FrameTimeIdx] = bx::getHPCounter();
+        ++FrameTimeIdx;
+        if (FrameTimeIdx >= FrameTimeBufSize) FrameTimeIdx = 0;
+    }
 } // namespace Tools
diff --git a/src/game/Tools.h b/src/game/Tools.h
index 87f1e44..827f90e 100644
--- a/src/game/Tools.h
+++ b/src/game/Tools.h
@@ -7,4 +7,5 @@ namespace Tools
     void ModelDropdown(Generated::ModelHandle& modelHandle);
     void TextureDropdown(Generated::TextureHandle& texHandle);
     void RenderDebugUI(Game::GameRendering& rendering);
+    void MeasureFrameEnd();
 } // namespace Tools