Fixed incorrect FixedUpdate() execution and added Time.FixedDeltaTime

SHADE_Engine/src/Physics/SHPhysicsSystem.cpp

@@ -327,6 +327,11 @@ namespace SHADE
   void SHPhysicsSystem::PhysicsFixedUpdate::Execute(double dt) noexcept
   {
     auto* physicsSystem = reinterpret_cast<SHPhysicsSystem*>(GetSystem());
+    auto scriptSys = SHSystemManager::GetSystem<SHScriptEngine>();
+    if (!scriptSys)
+    {
+        SHLOG_WARNING("[SHPhysicsSystem] Unable to invoke FixedUpdate() on scripts due to missing SHScriptEngine!");
+    }
 
     fixedTimeStep = 1.0 / physicsSystem->fixedDT;
     accumulatedTime += dt;
@@ -334,6 +339,10 @@ namespace SHADE
     int count = 0;
     while (accumulatedTime > fixedTimeStep)
     {
+      if (scriptSys)
+      {
+        scriptSys->ExecuteFixedUpdates();
+      }
       physicsSystem->world->update(static_cast<rp3d::decimal>(fixedTimeStep));
 
       accumulatedTime -= fixedTimeStep;
@@ -359,7 +368,6 @@ namespace SHADE
       auto scriptSys = SHSystemManager::GetSystem<SHScriptEngine>();
       if (scriptSys)
       {
-        scriptSys->ExecuteFixedUpdates();
         scriptSys->ExecuteCollisionFunctions();
       }
       else

SHADE_Engine/src/Physics/SHPhysicsSystemInterface.cpp

@@ -50,4 +50,16 @@ namespace SHADE
     SHLOG_WARNING("[SHPhysicsSystemInterface] Failed to get trigger events. Empty vector returned instead.");
     return emptyVec;
   }
+
+  double SHPhysicsSystemInterface::GetFixedDT() noexcept
+  {
+    auto phySystem = SHSystemManager::GetSystem<SHPhysicsSystem>();
+    if (phySystem)
+    {
+      return phySystem->GetFixedDT();
+    }
+
+    SHLOG_WARNING("[SHPhysicsSystemInterface] Failed to get fixed delta time. 0.0 returned instead.");
+    return 0.0;
+  }
 }

SHADE_Engine/src/Physics/SHPhysicsSystemInterface.h

@@ -41,5 +41,6 @@ namespace SHADE
     /*---------------------------------------------------------------------------------*/
     [[nodiscard]] static const std::vector<SHCollisionEvent>& GetCollisionInfo() noexcept;
     [[nodiscard]] static const std::vector<SHCollisionEvent>& GetTriggerInfo() noexcept;
+    [[nodiscard]] static double GetFixedDT() noexcept;
   };
 }

SHADE_Managed/src/Engine/Time.cxx

@@ -14,6 +14,9 @@ of DigiPen Institute of Technology is prohibited.
 *//*************************************************************************************/
 // Precompiled Headers
 #include "SHpch.h"
+// External Dependencies
+#include "FRC/SHFramerateController.h"
+#include "Physics/SHPhysicsSystemInterface.h"
 // Primary Header
 #include "Time.hxx"
 
@@ -26,4 +29,8 @@ namespace SHADE
     {
         return SHFrameRateController::GetRawDeltaTime();
     }
+    double Time::FixedDeltaTime::get()
+    {
+        return SHPhysicsSystemInterface::GetFixedDT();
+    }
 }

SHADE_Managed/src/Engine/Time.hxx

@@ -14,8 +14,6 @@ of DigiPen Institute of Technology is prohibited.
 *//*************************************************************************************/
 #pragma once
 
-#include "FRC/SHFramerateController.h"
-
 namespace SHADE
 {
     /// <summary>
@@ -29,13 +27,18 @@ namespace SHADE
         /*-----------------------------------------------------------------------------*/
         /// <summary>
         /// Time taken to process the previous frame.
-        /// Note, is affected by TimeScale. Use UnscaledDeltaTime if you wish to retrieve
-        /// real world time. This is also affected by MaxDeltaTime clamping that
-        /// UnscaledDeltaTime is subject to.
         /// </summary>
         static property double DeltaTime
         {
             double get();
         }
+        /// <summary>
+        /// Time taken for Physics simulations. You should use this for operations 
+        /// within Script.FixedUpdate()
+        /// </summary>
+        static property double FixedDeltaTime
+        {
+            double get();
+        }
     };
 }

TempScriptsFolder/PhysicsTest.cs

@@ -41,6 +41,11 @@ public class PhysicsTest : Script
         Debug.Log($"{Transform.LocalPosition.y}");
     }
 
+    protected override void fixedUpdate()
+    {
+        Debug.Log("Fixed Update");
+    }
+
     protected override void onCollisionEnter(CollisionInfo info)
     {
         Debug.Log($"Collision Enter: {info.GameObject.Name}");