Show RAM usage (max rss) in UI for Linux systems (#18)

Compiler warning will display for other platforms and default to showing 0.

Author: htmlboss

MP-APS/Core/GUISystem.cpp

@@ -49,16 +49,17 @@ void GUISystem::Render(const int framebufferWidth,
 nk_glfw3_new_frame();
 
 const auto frameStatFlags = NK_WINDOW_BORDER | NK_WINDOW_NO_SCROLLBAR | NK_WINDOW_NO_INPUT;
-if (nk_begin(m_nuklearContext, "Frame Stats", nk_rect(0, framebufferHeight - 40, 500, 40), frameStatFlags)) {
+if (nk_begin(m_nuklearContext, "Frame Stats", nk_rect(0, framebufferHeight - 40, 720, 40), frameStatFlags)) {
 nk_layout_row_begin(m_nuklearContext, NK_STATIC, 0, 1);
 {
-nk_layout_row_push(m_nuklearContext, 500);
+nk_layout_row_push(m_nuklearContext, 720);
  nk_label(
 m_nuklearContext,
-fmt::format("Frame Time: {:.2f} ms ({:.0f} fps) | GPU VRAM Usage: {} MB",
+fmt::format("Frame Time: {:.2f} ms ({:.0f} fps) | GPU VRAM Usage: {} MB | RAM Usage: {} MB",
 frameStats.frameTimeMilliseconds,
 1.0 / (frameStats.frameTimeMilliseconds / 1000.0),
-frameStats.videoMemoryUsageKB / 1000
+frameStats.videoMemoryUsageKB / 1000,
+frameStats.ramUsageKB / 1000
 ).c_str(),
 NK_TEXT_LEFT
 );

MP-APS/Engine.cpp

@@ -6,6 +6,7 @@
 #include "ResourceManager.h"
 #include "SceneBase.h"
 #include "FrameStats.h"
+#include "Platform/Platform.h"
 
 #include <GLFW/glfw3.h>
 #include <pugixml.hpp>
@@ -120,6 +121,7 @@ void Engine::Execute() {
 const auto frameTime{ frameTimeMilliseconds(numFramesRendered) };
 frameStats.frameTimeMilliseconds = frameTime;
 frameStats.videoMemoryUsageKB = m_renderer.GetVideoMemUsageKB();
+frameStats.ramUsageKB = Platform::maxRSSKb();
 
 numFramesRendered = 0;
 hasOneSecondPassed = false;

MP-APS/FrameStats.h

@@ -3,4 +3,5 @@
 struct FrameStats {
  double frameTimeMilliseconds{ 0.0 };
  int videoMemoryUsageKB{ 0 };
+ long ramUsageKB{ 0 };
 };

MP-APS/Platform/Platform.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#ifdef __linux__
+ #include <sys/resource.h>
+#endif
+
+namespace Platform {
+ long maxRSSKb() noexcept {
+#ifdef __linux__
+ // https://man7.org/linux/man-pages/man2/getrusage.2.html
+ rusage ru;
+ const auto result{ getrusage(RUSAGE_SELF, &ru) };
+
+ if (result == -1) {
+ return 0;
+ }
+
+ return ru.ru_maxrss;
+#else
+ #warning "Platform::maxRSSKb not implemented for this platform."
+ return 0;
+#endif
+ }
+};