Replace data structure for HW buffer book-keeping

before
  time in endScene ÷ num hw buf ________________  199x   0.128
after
  time in endScene ÷ num hw buf ________________  199x   0.057

irr/src/CNullDriver.cpp

@@ -218,7 +218,7 @@ bool CNullDriver::beginScene(u16 clearFlag, SColor clearColor, f32 clearDepth, u
 bool CNullDriver::endScene()
 {
 	FPSCounter.registerFrame(os::Timer::getRealTime());
-	updateAllHardwareBuffers();
+	expireHardwareBuffers();
 	updateAllOcclusionQueries();
 	return true;
 }
@@ -1141,25 +1141,28 @@ CNullDriver::SHWBufferLink *CNullDriver::getBufferLink(const scene::IIndexBuffer
 	return createHardwareBuffer(ib); // no hardware links, and mesh wants one, create it
 }
 
-//! Update all hardware buffers, remove unused ones
+void CNullDriver::registerHardwareBuffer(SHWBufferLink *HWBuffer)
-void CNullDriver::updateAllHardwareBuffers()
 {
-	// FIXME: this method can take a lot of time just doing the refcount
+	_IRR_DEBUG_BREAK_IF(!HWBuffer)
-	// checks and iteration (too much pointer chasing?) for
+	HWBuffer->ListPosition = HWBufferList.size();
-	// large buffer counts (e.g. 50000)
+	HWBufferList.push_back(HWBuffer);
+}
 
-	auto it = HWBufferList.begin();
+void CNullDriver::expireHardwareBuffers()
-	while (it != HWBufferList.end()) {
+{
-		SHWBufferLink *Link = *it;
+	for (size_t i = 0; i < HWBufferList.size(); ) {
-		++it;
+		auto *Link = HWBufferList[i];
 
-		if (Link->IsVertex) {
+		bool del;
-			if (!Link->VertexBuffer || Link->VertexBuffer->getReferenceCount() == 1)
+		if (Link->IsVertex)
-				deleteHardwareBuffer(Link);
+			del = !Link->VertexBuffer || Link->VertexBuffer->getReferenceCount() == 1;
-		} else {
+		else
-			if (!Link->IndexBuffer || Link->IndexBuffer->getReferenceCount() == 1)
+			del = !Link->IndexBuffer || Link->IndexBuffer->getReferenceCount() == 1;
-				deleteHardwareBuffer(Link);
+		// deleting can reorder, so don't advance in list
-		}
+		if (del)
+			deleteHardwareBuffer(Link);
+		else
+			i++;
 	}
 
 	FrameStats.HWBuffersActive = HWBufferList.size();
@@ -1169,7 +1172,16 @@ void CNullDriver::deleteHardwareBuffer(SHWBufferLink *HWBuffer)
 {
 	if (!HWBuffer)
 		return;
-	HWBufferList.erase(HWBuffer->listPosition);
+	const size_t pos = HWBuffer->ListPosition;
+	_IRR_DEBUG_BREAK_IF(HWBufferList.at(pos) != HWBuffer)
+	if (HWBufferList.size() < 2 || pos == HWBufferList.size() - 1) {
+		HWBufferList.erase(HWBufferList.begin() + pos);
+	} else {
+		// swap with last
+		std::swap(HWBufferList[pos], HWBufferList.back());
+		HWBufferList.pop_back();
+		HWBufferList[pos]->ListPosition = pos;
+	}
 	delete HWBuffer;
 }
 

irr/src/CNullDriver.h

@@ -17,7 +17,6 @@
 #include "S3DVertex.h"
 #include "SVertexIndex.h"
 #include "SExposedVideoData.h"
-#include <list>
 
 namespace irr
 {
@@ -293,7 +292,7 @@ protected:
 	struct SHWBufferLink
 	{
 		SHWBufferLink(const scene::IVertexBuffer *vb) :
-				VertexBuffer(vb), ChangedID(0), IsVertex(true)
+				VertexBuffer(vb), IsVertex(true)
 		{
 			if (VertexBuffer) {
 				VertexBuffer->grab();
@@ -301,7 +300,7 @@ protected:
 			}
 		}
 		SHWBufferLink(const scene::IIndexBuffer *ib) :
-				IndexBuffer(ib), ChangedID(0), IsVertex(false)
+				IndexBuffer(ib), IsVertex(false)
 		{
 			if (IndexBuffer) {
 				IndexBuffer->grab();
@@ -324,9 +323,9 @@ protected:
 			const scene::IVertexBuffer *VertexBuffer;
 			const scene::IIndexBuffer *IndexBuffer;
 		};
-		u32 ChangedID;
+		size_t ListPosition = static_cast<size_t>(-1);
+		u32 ChangedID = 0;
 		bool IsVertex;
-		std::list<SHWBufferLink*>::iterator listPosition;
 	};
 
 	//! Gets hardware buffer link from a vertex buffer (may create or update buffer)
@@ -361,8 +360,8 @@ public:
 	//! Remove all hardware buffers
 	void removeAllHardwareBuffers() override;
 
-	//! Update all hardware buffers, remove unused ones
+	//! Run garbage-collection on all HW buffers
-	virtual void updateAllHardwareBuffers();
+	void expireHardwareBuffers();
 
 	//! is vbo recommended?
 	virtual bool isHardwareBufferRecommend(const scene::IVertexBuffer *mb);
@@ -582,6 +581,9 @@ protected:
 	//! deletes all material renderers
 	void deleteMaterialRenders();
 
+	// adds a created hardware buffer to the relevant data structure
+	void registerHardwareBuffer(SHWBufferLink *HWBuffer);
+
 	// prints renderer version
 	void printVersion();
 
@@ -705,7 +707,7 @@ protected:
 	core::array<video::IImageWriter *> SurfaceWriter;
 	core::array<SMaterialRenderer> MaterialRenderers;
 
-	std::list<SHWBufferLink *> HWBufferList;
+	std::vector<SHWBufferLink *> HWBufferList;
 
 	io::IFileSystem *FileSystem;
 

irr/src/COpenGLDriver.cpp

@@ -430,9 +430,7 @@ COpenGLDriver::SHWBufferLink *COpenGLDriver::createHardwareBuffer(const scene::I
 		return 0;
 
 	SHWBufferLink_opengl *HWBuffer = new SHWBufferLink_opengl(vb);
-
+	registerHardwareBuffer(HWBuffer);
-	// add to map
-	HWBuffer->listPosition = HWBufferList.insert(HWBufferList.end(), HWBuffer);
 
 	if (!updateVertexHardwareBuffer(HWBuffer)) {
 		deleteHardwareBuffer(HWBuffer);
@@ -453,9 +451,7 @@ COpenGLDriver::SHWBufferLink *COpenGLDriver::createHardwareBuffer(const scene::I
 		return 0;
 
 	SHWBufferLink_opengl *HWBuffer = new SHWBufferLink_opengl(ib);
-
+	registerHardwareBuffer(HWBuffer);
-	// add to map
-	HWBuffer->listPosition = HWBufferList.insert(HWBufferList.end(), HWBuffer);
 
 	if (!updateIndexHardwareBuffer(HWBuffer)) {
 		deleteHardwareBuffer(HWBuffer);

irr/src/OpenGL/Driver.cpp

@@ -566,10 +566,8 @@ COpenGL3DriverBase::SHWBufferLink *COpenGL3DriverBase::createHardwareBuffer(cons
 	if (!vb || vb->getHardwareMappingHint() == scene::EHM_NEVER)
 		return 0;
 
-	SHWBufferLink_opengl *HWBuffer = new SHWBufferLink_opengl(vb);
+	auto *HWBuffer = new SHWBufferLink_opengl(vb);
-
+	registerHardwareBuffer(HWBuffer);
-	// add to map
-	HWBuffer->listPosition = HWBufferList.insert(HWBufferList.end(), HWBuffer);
 
 	if (!updateVertexHardwareBuffer(HWBuffer)) {
 		deleteHardwareBuffer(HWBuffer);
@@ -584,10 +582,8 @@ COpenGL3DriverBase::SHWBufferLink *COpenGL3DriverBase::createHardwareBuffer(cons
 	if (!ib || ib->getHardwareMappingHint() == scene::EHM_NEVER)
 		return 0;
 
-	SHWBufferLink_opengl *HWBuffer = new SHWBufferLink_opengl(ib);
+	auto *HWBuffer = new SHWBufferLink_opengl(ib);
-
+	registerHardwareBuffer(HWBuffer);
-	// add to map
-	HWBuffer->listPosition = HWBufferList.insert(HWBufferList.end(), HWBuffer);
 
 	if (!updateIndexHardwareBuffer(HWBuffer)) {
 		deleteHardwareBuffer(HWBuffer);