From e02aece40ad55a16bb9c7024ef736af0fcdf09a1 Mon Sep 17 00:00:00 2001
From: Magnus Norddahl <dpjudas@users.noreply.github.com>
Date: Sun, 15 Jan 2017 21:45:21 +0100
Subject: [PATCH] Added a generic memory allocator for memory needed for a
 frame

---
 src/swrenderer/plane/r_visibleplane.cpp |  5 +--
 src/swrenderer/r_memory.cpp             | 48 +++++++++++++++++--------
 src/swrenderer/r_memory.h               | 44 +++++++++++++++++++++--
 src/swrenderer/scene/r_scene.cpp        |  3 +-
 4 files changed, 78 insertions(+), 22 deletions(-)

diff --git a/src/swrenderer/plane/r_visibleplane.cpp b/src/swrenderer/plane/r_visibleplane.cpp
index fbb1e37a0..a1928bbb8 100644
--- a/src/swrenderer/plane/r_visibleplane.cpp
+++ b/src/swrenderer/plane/r_visibleplane.cpp
@@ -65,10 +65,7 @@ namespace swrenderer
 				}
 				if (!found)
 				{
-					visplane_light *newlight = R_NewPlaneLight();
-					if (!newlight)
-						return;
-
+					visplane_light *newlight = RenderMemory::NewObject<visplane_light>();
 					newlight->next = lights;
 					newlight->lightsource = node->lightsource;
 					lights = newlight;
diff --git a/src/swrenderer/r_memory.cpp b/src/swrenderer/r_memory.cpp
index 0893f6936..b4faa44cd 100644
--- a/src/swrenderer/r_memory.cpp
+++ b/src/swrenderer/r_memory.cpp
@@ -72,23 +72,43 @@ namespace swrenderer
 	}
 
 	/////////////////////////////////////////////////////////////////////////
-
-	namespace
+	
+	void *RenderMemory::AllocBytes(int size)
 	{
-		enum { max_plane_lights = 32 * 1024 };
-		visplane_light plane_lights[max_plane_lights];
-		int next_plane_light = 0;
-	}
+		size = (size + 15) / 16 * 16; // 16-byte align
+		
+		if (UsedBlocks.empty() || UsedBlocks.back()->Position + size > BlockSize)
+		{
+			if (!FreeBlocks.empty())
+			{
+				auto block = std::move(FreeBlocks.back());
+				block->Position = 0;
+				FreeBlocks.pop_back();
+				UsedBlocks.push_back(std::move(block));
+			}
+			else
+			{
+				UsedBlocks.push_back(std::make_unique<MemoryBlock>());
+			}
+		}
+		
+		auto &block = UsedBlocks.back();
+		void *data = block->Data + block->Position;
+		block->Position += size;
 
-	visplane_light *R_NewPlaneLight()
-	{
-		if (next_plane_light == max_plane_lights)
-			return nullptr;
-		return &plane_lights[next_plane_light++];
+		return data;
 	}
-
-	void R_FreePlaneLights()
+	
+	void RenderMemory::Clear()
 	{
-		next_plane_light = 0;
+		while (!UsedBlocks.empty())
+		{
+			auto block = std::move(UsedBlocks.back());
+			UsedBlocks.pop_back();
+			FreeBlocks.push_back(std::move(block));
+		}
 	}
+	
+	std::vector<std::unique_ptr<RenderMemory::MemoryBlock>> RenderMemory::UsedBlocks;
+	std::vector<std::unique_ptr<RenderMemory::MemoryBlock>> RenderMemory::FreeBlocks;
 }
diff --git a/src/swrenderer/r_memory.h b/src/swrenderer/r_memory.h
index 7914cdfcf..0bf86f2cd 100644
--- a/src/swrenderer/r_memory.h
+++ b/src/swrenderer/r_memory.h
@@ -13,6 +13,8 @@
 
 #pragma once
 
+#include <memory>
+
 namespace swrenderer
 {
 	struct visplane_light;
@@ -22,7 +24,43 @@ namespace swrenderer
 	ptrdiff_t R_NewOpening(ptrdiff_t len);
 	void R_FreeOpenings();
 	void R_DeinitOpenings();
-
-	visplane_light *R_NewPlaneLight();
-	void R_FreePlaneLights();
+	
+	// Memory needed for the duration of a frame rendering
+	class RenderMemory
+	{
+	public:
+		static void Clear();
+		
+		template<typename T>
+		static T *AllocMemory(int size = 1)
+		{
+			return (T*)AllocBytes(sizeof(T) * size);
+		}
+		
+		template<typename T, typename... Types>
+		static T *NewObject(Types &&... args)
+		{
+			void *ptr = AllocBytes(sizeof(T));
+			return new (ptr)T(std::forward<Types>(args)...);
+		}
+		
+	private:
+		static void *AllocBytes(int size);
+		
+		enum { BlockSize = 1024 * 1024 };
+		
+		struct MemoryBlock
+		{
+			MemoryBlock() : Data(new uint8_t[BlockSize]), Position(0) { }
+			~MemoryBlock() { delete[] Data; }
+			
+			MemoryBlock(const MemoryBlock &) = delete;
+			MemoryBlock &operator=(const MemoryBlock &) = delete;
+			
+			uint8_t *Data;
+			uint32_t Position;
+		};
+		static std::vector<std::unique_ptr<MemoryBlock>> UsedBlocks;
+		static std::vector<std::unique_ptr<MemoryBlock>> FreeBlocks;
+	};
 }
diff --git a/src/swrenderer/scene/r_scene.cpp b/src/swrenderer/scene/r_scene.cpp
index f2f56b833..71740aefc 100644
--- a/src/swrenderer/scene/r_scene.cpp
+++ b/src/swrenderer/scene/r_scene.cpp
@@ -117,6 +117,8 @@ namespace swrenderer
 		PlaneCycles.Reset();
 		MaskedCycles.Reset();
 		WallScanCycles.Reset();
+		
+		RenderMemory::Clear();
 
 		Clip3DFloors *clip3d = Clip3DFloors::Instance();
 		clip3d->Cleanup();
@@ -132,7 +134,6 @@ namespace swrenderer
 		R_ClearClipSegs(0, viewwidth);
 		R_ClearDrawSegs();
 		VisiblePlaneList::Instance()->Clear(true);
-		R_FreePlaneLights();
 		RenderTranslucentPass::Clear();
 
 		// opening / clipping determination