4 files changed, 72 insertions, 4 deletions
diff --git a/launcher/minecraft/MinecraftInstance.cpp b/launcher/minecraft/MinecraftInstance.cpp
index 88b1f7f3..889c6dde 100644
--- a/launcher/minecraft/MinecraftInstance.cpp
+++ b/launcher/minecraft/MinecraftInstance.cpp
@@ -154,6 +154,12 @@ MinecraftInstance::MinecraftInstance(SettingsObjectPtr globalSettings, SettingsO
     m_settings->registerOverride(globalSettings->getSetting("UseNativeOpenAL"), nativeLibraryWorkaroundsOverride);
     m_settings->registerOverride(globalSettings->getSetting("UseNativeGLFW"), nativeLibraryWorkaroundsOverride);
 
+    // Peformance related options
+    auto performanceOverride = m_settings->registerSetting("OverridePerformance", false);
+    m_settings->registerOverride(globalSettings->getSetting("EnableFeralGamemode"), performanceOverride);
+    m_settings->registerOverride(globalSettings->getSetting("EnableMangoHud"), performanceOverride);
+    m_settings->registerOverride(globalSettings->getSetting("UseDiscreteGpu"), performanceOverride);
+
     // Game time
     auto gameTimeOverride = m_settings->registerSetting("OverrideGameTime", false);
     m_settings->registerOverride(globalSettings->getSetting("ShowGameTime"), gameTimeOverride);
@@ -435,6 +441,36 @@ QProcessEnvironment MinecraftInstance::createEnvironment()
     return env;
 }
 
+QProcessEnvironment MinecraftInstance::createLaunchEnvironment()
+{
+    // prepare the process environment
+    QProcessEnvironment env = createEnvironment();
+
+#ifdef Q_OS_LINUX
+    if (settings()->get("EnableMangoHud").toBool())
+    {
+        auto preload = env.value("LD_PRELOAD", "") + ":libMangoHud_dlsym.so:libMangoHud.so";
+        auto lib_path = env.value("LD_LIBRARY_PATH", "") +  ":/usr/local/$LIB/mangohud/:/usr/$LIB/mangohud/";
+
+        env.insert("LD_PRELOAD", preload);
+        env.insert("LD_LIBRARY_PATH", lib_path);
+        env.insert("MANGOHUD", "1");
+    }
+
+    if (settings()->get("UseDiscreteGpu").toBool())
+    {
+        // Open Source Drivers
+        env.insert("DRI_PRIME", "1");
+        // Proprietary Nvidia Drivers
+        env.insert("__NV_PRIME_RENDER_OFFLOAD", "1");
+        env.insert("__VK_LAYER_NV_optimus", "NVIDIA_only");
+        env.insert("__GLX_VENDOR_LIBRARY_NAME", "nvidia");
+    }
+#endif
+
+    return env;
+}
+
 static QString replaceTokensIn(QString text, QMap<QString, QString> with)
 {
     QString result;
diff --git a/launcher/minecraft/MinecraftInstance.h b/launcher/minecraft/MinecraftInstance.h
index fda58aa7..05450d41 100644
--- a/launcher/minecraft/MinecraftInstance.h
+++ b/launcher/minecraft/MinecraftInstance.h
@@ -91,6 +91,7 @@ public:
 
     /// create an environment for launching processes
     QProcessEnvironment createEnvironment() override;
+    QProcessEnvironment createLaunchEnvironment() override;
 
     /// guess log level from a line of minecraft log
     MessageLevel::Enum guessLevel(const QString &line, MessageLevel::Enum level) override;
diff --git a/launcher/minecraft/launch/DirectJavaLaunch.cpp b/launcher/minecraft/launch/DirectJavaLaunch.cpp
index 742170fa..152485b3 100644
--- a/launcher/minecraft/launch/DirectJavaLaunch.cpp
+++ b/launcher/minecraft/launch/DirectJavaLaunch.cpp
@@ -12,13 +12,18 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 #include "DirectJavaLaunch.h"
+
+#include <QStandardPaths>
+
 #include <launch/LaunchTask.h>
 #include <minecraft/MinecraftInstance.h>
 #include <FileSystem.h>
 #include <Commandline.h>
-#include <QStandardPaths>
+
+#ifdef Q_OS_LINUX
+#include "gamemode_client.h"
+#endif
 
 DirectJavaLaunch::DirectJavaLaunch(LaunchTask *parent) : LaunchStep(parent)
 {
@@ -50,7 +55,7 @@ void DirectJavaLaunch::executeTask()
 
     auto javaPath = FS::ResolveExecutable(instance->settings()->get("JavaPath").toString());
 
-    m_process.setProcessEnvironment(instance->createEnvironment());
+    m_process.setProcessEnvironment(instance->createLaunchEnvironment());
 
     // make detachable - this will keep the process running even if the object is destroyed
     m_process.setDetachable(true);
@@ -79,6 +84,17 @@ void DirectJavaLaunch::executeTask()
     {
         m_process.start(javaPath, args);
     }
+
+#ifdef Q_OS_LINUX
+    if (instance->settings()->get("EnableFeralGamemode").toBool())
+    {
+        auto pid = m_process.processId();
+        if (pid)
+        {
+            gamemode_request_start_for(pid);
+        }
+    }
+#endif
 }
 
 void DirectJavaLaunch::on_state(LoggedProcess::State state)
diff --git a/launcher/minecraft/launch/LauncherPartLaunch.cpp b/launcher/minecraft/launch/LauncherPartLaunch.cpp
index 3ed5e957..9965ef89 100644
--- a/launcher/minecraft/launch/LauncherPartLaunch.cpp
+++ b/launcher/minecraft/launch/LauncherPartLaunch.cpp
@@ -44,6 +44,10 @@
 #include "Commandline.h"
 #include "Application.h"
 
+#ifdef Q_OS_LINUX
+#include "gamemode_client.h"
+#endif
+
 LauncherPartLaunch::LauncherPartLaunch(LaunchTask *parent) : LaunchStep(parent)
 {
     auto instance = parent->instance();
@@ -111,7 +115,7 @@ void LauncherPartLaunch::executeTask()
 
     auto javaPath = FS::ResolveExecutable(instance->settings()->get("JavaPath").toString());
 
-    m_process.setProcessEnvironment(instance->createEnvironment());
+    m_process.setProcessEnvironment(instance->createLaunchEnvironment());
 
     // make detachable - this will keep the process running even if the object is destroyed
     m_process.setDetachable(true);
@@ -176,6 +180,17 @@ void LauncherPartLaunch::executeTask()
     {
         m_process.start(javaPath, args);
     }
+
+#ifdef Q_OS_LINUX
+    if (instance->settings()->get("EnableFeralGamemode").toBool())
+    {
+        auto pid = m_process.processId();
+        if (pid)
+        {
+            gamemode_request_start_for(pid);
+        }
+    }
+#endif
 }
 
 void LauncherPartLaunch::on_state(LoggedProcess::State state)