From 600603ce9269c10e9e08186454e74c2f3b0a6ff2 Mon Sep 17 00:00:00 2001
From: Steve Streeting <steve@stevestreeting.com>
Date: Thu, 3 Nov 2022 12:18:34 +0000
Subject: [PATCH] Fix #6: Change InputImage update delay to a tickable

Previously used a timer but timers cannot run while game is paused, and UI images should update regardless.
---
 .../Private/StevesUI/InputImage.cpp           | 49 ++++++++++++++++---
 .../Public/StevesUI/InputImage.h              | 20 ++++++--
 2 files changed, 59 insertions(+), 10 deletions(-)

diff --git a/Source/StevesUEHelpers/Private/StevesUI/InputImage.cpp b/Source/StevesUEHelpers/Private/StevesUI/InputImage.cpp
index 68db7be..5291725 100644
--- a/Source/StevesUEHelpers/Private/StevesUI/InputImage.cpp
+++ b/Source/StevesUEHelpers/Private/StevesUI/InputImage.cpp
@@ -107,15 +107,50 @@ void UInputImage::UpdateImage()
             SetBrushFromAtlasInterface(Sprite, true);
         }
     }
-    DelayedUpdateImageTimer.Invalidate();
+    bIsDirty = false;
+    DelayUpdate = 0;
 }
 
 void UInputImage::MarkImageDirty()
 {
-    if (!DelayedUpdateImageTimer.IsValid())
-    {
-        // Delayed update
-        GetWorld()->GetTimerManager().SetTimer(DelayedUpdateImageTimer, this, &UInputImage::UpdateImage, 0.5f);
-    }
-
+    bIsDirty = true;
+    DelayUpdate = 0.5f;
 }
+
+// Tickables
+// We need a tick rather than FTimer because timers won't run when game is paused, and UIs are useful while paused! 
+ETickableTickType UInputImage::GetTickableTickType() const
+{
+    return ETickableTickType::Conditional;
+}
+bool UInputImage::IsTickableWhenPaused() const
+{
+    // UIs need to update while game is paused
+    return true;
+}
+bool UInputImage::IsTickableInEditor() const
+{
+    return false;
+}
+
+bool UInputImage::IsTickable() const
+{
+    // Only need to tick while dirty
+    return bIsDirty;
+}
+
+void UInputImage::Tick(float DeltaTime)
+{
+    DelayUpdate -= DeltaTime;
+    if (DelayUpdate <= 0)
+    {
+        UpdateImage();
+    }
+}
+
+TStatId UInputImage::GetStatId() const
+{
+    RETURN_QUICK_DECLARE_CYCLE_STAT( UInputImage, STATGROUP_Tickables );
+}
+
+// Tickables
diff --git a/Source/StevesUEHelpers/Public/StevesUI/InputImage.h b/Source/StevesUEHelpers/Public/StevesUI/InputImage.h
index ab77863..a30843c 100644
--- a/Source/StevesUEHelpers/Public/StevesUI/InputImage.h
+++ b/Source/StevesUEHelpers/Public/StevesUI/InputImage.h
@@ -10,7 +10,7 @@
 /// A special widget containing an image which populates itself based on an input action / axis and can dynamically
 /// change based on the active input method.
 UCLASS()
-class STEVESUEHELPERS_API UInputImage : public UImage
+class STEVESUEHELPERS_API UInputImage : public UImage, public FTickableGameObject
 {
     GENERATED_BODY()
 
@@ -39,9 +39,13 @@ protected:
     UPROPERTY(EditAnywhere)   
     UUiTheme* CustomTheme;
 
-    bool bSubbedToInputEvents = false;
+    UPROPERTY(EditAnywhere)   
+    bool bUpdateWhilePaused = true;
+
+    bool bSubbedToInputEvents = false;
+    bool bIsDirty = true;
+    float DelayUpdate = 0;
 
-    FTimerHandle DelayedUpdateImageTimer;
 public:
 
     /// Tell this image to display the bound action for the current input method
@@ -76,6 +80,16 @@ public:
     virtual void BeginDestroy() override;
 
     virtual void SetVisibility(ESlateVisibility InVisibility) override;
+
+    // FTickableGameObject begin
+    virtual void Tick(float DeltaTime) override;
+    virtual TStatId GetStatId() const override;
+    virtual bool IsTickableWhenPaused() const override;
+    virtual bool IsTickableInEditor() const override;
+    virtual bool IsTickable() const override;
+    virtual ETickableTickType GetTickableTickType() const override;
+    // FTickableGameObject end
+    
     
 protected: