From f279fa69f4c02d34790332bcb84b8f0771bf63e3 Mon Sep 17 00:00:00 2001
From: RaveYard <29225776+MrRaveYard@users.noreply.github.com>
Date: Sat, 9 Sep 2023 17:42:57 +0200
Subject: [PATCH] WIP refactoring of surface gathering

---
 .../hwrenderer/data/hw_renderstate.h          | 29 ++++++++++--
 src/rendering/hwrenderer/hw_entrypoint.cpp    | 46 +++++++++++--------
 2 files changed, 52 insertions(+), 23 deletions(-)

diff --git a/src/common/rendering/hwrenderer/data/hw_renderstate.h b/src/common/rendering/hwrenderer/data/hw_renderstate.h
index 97ffba4b06..5b5fa72fac 100644
--- a/src/common/rendering/hwrenderer/data/hw_renderstate.h
+++ b/src/common/rendering/hwrenderer/data/hw_renderstate.h
@@ -10,6 +10,8 @@
 #include "hw_viewpointuniforms.h"
 #include "hw_cvars.h"
 
+#include <atomic>
+
 EXTERN_CVAR(Int, lm_max_updates);
 
 struct FColormap;
@@ -260,13 +262,17 @@ protected:
 
 	EPassType mPassType = NORMAL_PASS;
 
-	TArray<int> mActiveLightmapSurfaces;
+	std::atomic<unsigned> mActiveLightmapSurfaceBufferIndex;
+	TArray<int> mActiveLightmapSurfacesBuffer;
 public:
 
 	uint64_t firstFrame = 0;
 
 	void Reset()
 	{
+		mActiveLightmapSurfaceBufferIndex = { 0 };
+		mActiveLightmapSurfacesBuffer.Resize(lm_max_updates);
+
 		mTextureEnabled = true;
 		mBrightmapEnabled = mGradientEnabled = mFogEnabled = mGlowEnabled = false;
 		mFogColor = 0xffffffff;
@@ -735,18 +741,31 @@ public:
 
 	inline void PushVisibleSurface(int surfaceIndex, LevelMeshSurface* surface)
 	{
-		if(surface->needsUpdate && mActiveLightmapSurfaces.Size() < unsigned(lm_max_updates) && mActiveLightmapSurfaces.Find(surfaceIndex) >= mActiveLightmapSurfaces.Size()) // yikes, how awful
-			mActiveLightmapSurfaces.Push(surfaceIndex);
+		if (surface->needsUpdate) // TODO atomic? 
+		{
+			int index = mActiveLightmapSurfaceBufferIndex.fetch_add(1);
+			if (index < mActiveLightmapSurfacesBuffer.Size())
+			{
+				mActiveLightmapSurfacesBuffer[index] = surfaceIndex;
+				surface->needsUpdate = false;
+			}
+		}
 	}
 
 	inline auto& GetVisibleSurfaceList()
 	{
-		return mActiveLightmapSurfaces;
+		return mActiveLightmapSurfacesBuffer;
+	}
+
+	inline unsigned GetVisibleSurfaceListCount() const
+	{
+		return mActiveLightmapSurfaceBufferIndex;
 	}
 
 	inline void ClearVisibleSurfaceList()
 	{
-		mActiveLightmapSurfaces.Clear();
+		mActiveLightmapSurfacesBuffer.Resize(lm_max_updates);
+		mActiveLightmapSurfaceBufferIndex = 0;
 	}
 
 	// API-dependent render interface
diff --git a/src/rendering/hwrenderer/hw_entrypoint.cpp b/src/rendering/hwrenderer/hw_entrypoint.cpp
index 5c9d50e649..9d434ae8ad 100644
--- a/src/rendering/hwrenderer/hw_entrypoint.cpp
+++ b/src/rendering/hwrenderer/hw_entrypoint.cpp
@@ -97,6 +97,33 @@ void CollectLights(FLevelLocals* Level)
 	}
 }
 
+void UpdateLightmaps(DFrameBuffer* screen, FRenderState& RenderState)
+{
+
+	// Lightmapping stuff
+	auto& list = RenderState.GetVisibleSurfaceList();
+	auto size = RenderState.GetVisibleSurfaceListCount();
+
+	list.Resize(min(list.Size(), unsigned(size)));
+
+	if (size < lm_background_updates)
+	{
+		int index = 0;
+		for (auto& e : level.levelMesh->Surfaces)
+		{
+			if (e.needsUpdate)
+			{
+				list.Push(index);
+
+				if (list.Size() >= lm_background_updates)
+					break;
+			}
+			++index;
+		}
+	}
+
+	screen->UpdateLightmaps(list);
+}
 
 //-----------------------------------------------------------------------------
 //
@@ -199,24 +226,7 @@ sector_t* RenderViewpoint(FRenderViewpoint& mainvp, AActor* camera, IntRect* bou
 			screen->NextEye(eyeCount);
 	}
 
-	auto& list = RenderState.GetVisibleSurfaceList();
-	if (list.Size() < lm_background_updates)
-	{
-		int index = 0;
-		for (auto& e : level.levelMesh->Surfaces)
-		{
-			if (e.needsUpdate)
-			{
-				list.Push(index);
-
-				if(list.Size() >= lm_background_updates)
-					break;
-			}
-			++index;
-		}
-	}
-
-	screen->UpdateLightmaps(list);
+	UpdateLightmaps(screen, RenderState);
 
 	return mainvp.sector;
 }