a lot of stuff

Plugins/DemoPlugin/Source/DemoPlugin/DemoPlugin.Build.cs

@@ -0,0 +1,17 @@
+using UnrealBuildTool;
+
+public class DemoPlugin : ModuleRules
+{
+    public DemoPlugin(ReadOnlyTargetRules Target) : base(Target)
+    {
+        PCHUsage = PCHUsageMode.UseExplicitOrSharedPCHs;
+
+        PublicDependencyModuleNames.AddRange(new[]
+        {
+            "Core",
+            "CoreUObject",
+            "Engine",
+            "ImageCore"
+        });
+    }
+}

Plugins/DemoPlugin/Source/DemoPlugin/Private/DemoPlugin.cpp

@@ -0,0 +1,8 @@
+#include "Modules/ModuleManager.h"
+
+IMPLEMENT_MODULE(FDefaultModuleImpl, DemoPlugin)
+
+//This registers that it is the implementation of DemoPlugin module 
+//that can be loaded by UE
+
+//Here could be startup scripts or sth

Plugins/DemoPlugin/Source/DemoPlugin/Private/DemoRenderBridge.cpp

@@ -0,0 +1,51 @@
+#include "DemoRenderBridge.h"
+
+#include "Engine/TextureRenderTarget2D.h"
+#include "ImageCore.h"
+#include "ImageUtils.h"
+
+bool UDemoRenderBridge::RenderTargetToPng(
+    UTextureRenderTarget2D* RenderTarget,
+    TArray<uint8>& OutPngBytes,
+    FString& OutError)
+{
+    OutPngBytes.Reset();
+    OutError.Reset();
+
+    if (!IsInGameThread())
+    {
+        OutError = TEXT("Function must be ran on Game Thread");
+        return false;
+    }
+
+    if (!IsValid(RenderTarget))
+    {
+        OutError = TEXT("Render Target reference is invalid");
+        return false;
+    }
+
+    // Faktyczne wywolanie API C++ Unreala: odczyt Render Targetu do FImage.
+    FImage Image;
+    if (!FImageUtils::GetRenderTargetImage(RenderTarget, Image))
+    {
+        OutError = TEXT("Couldnt read Render Target");
+        return false;
+    }
+
+    // Faktyczne wywolanie API C++ Unreala: kompresja FImage do PNG w pamieci.
+    TArray64<uint8> Encoded;
+    if (!FImageUtils::CompressImage(Encoded, TEXT(".png"), Image, 0))
+    {
+        OutError = TEXT("Couldnt encode png");
+        return false;
+    }
+
+    if (Encoded.Num() > MAX_int32)
+    {
+        OutError = TEXT("Result too large");
+        return false;
+    }
+
+    OutPngBytes.Append(Encoded.GetData(), static_cast<int32>(Encoded.Num()));
+    return true;
+}

Plugins/DemoPlugin/Source/DemoPlugin/Public/DemoRenderBridge.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Kismet/BlueprintFunctionLibrary.h"
+#include "DemoRenderBridge.generated.h"
+
+class UTextureRenderTarget2D;
+
+/** Funkcje C++ dostepne w Blueprintach i Python API */
+UCLASS()
+class DEMOPLUGIN_API UDemoRenderBridge : public UBlueprintFunctionLibrary
+{
+    GENERATED_BODY()
+
+public:
+
+    /** Odczytuje Render Target z GPU i zwraca zakodowany PNG w pamieci. */
+    UFUNCTION(BlueprintCallable, Category = "Demo|C++ Bridge")
+    static bool RenderTargetToPng(
+        UTextureRenderTarget2D* RenderTarget,
+        TArray<uint8>& OutPngBytes,
+        FString& OutError);
+};