From a5e019d14324aa1201b54cc32e6dc9d0b95e4c6a Mon Sep 17 00:00:00 2001
From: baldurk <baldurk@baldurk.org>
Date: Wed, 3 Dec 2014 20:23:49 +0000
Subject: [PATCH] Fix glBufferData re-creating, preserve chunk ordering

---
 renderdoc/core/resource_manager.h             |  6 ++
 .../driver/gl/wrappers/gl_buffer_funcs.cpp    | 76 ++++++++++++++++---
 2 files changed, 71 insertions(+), 11 deletions(-)

diff --git a/renderdoc/core/resource_manager.h b/renderdoc/core/resource_manager.h
index c82dae48c..414cbf550 100644
--- a/renderdoc/core/resource_manager.h
+++ b/renderdoc/core/resource_manager.h
@@ -207,6 +207,12 @@ struct ResourceRecord
 		return m_Chunks.rbegin()->second;
 	}
 
+	int32_t GetLastChunkID() const
+	{
+		RDCASSERT(HasChunks());
+		return m_Chunks.rbegin()->first;
+	}
+
 	void PopChunk()
 	{
 		m_Chunks.erase(m_Chunks.rbegin()->first);
diff --git a/renderdoc/driver/gl/wrappers/gl_buffer_funcs.cpp b/renderdoc/driver/gl/wrappers/gl_buffer_funcs.cpp
index 508093ea4..cbd8ac4a6 100644
--- a/renderdoc/driver/gl/wrappers/gl_buffer_funcs.cpp
+++ b/renderdoc/driver/gl/wrappers/gl_buffer_funcs.cpp
@@ -356,24 +356,51 @@ void WrappedOpenGL::glNamedBufferDataEXT(GLuint buffer, GLsizeiptr size, const v
 		// data, but we don't support (if it's even possible) querying out size etc.
 		// we need to add only the chunks required - glGenBuffers, glBindBuffer to current target,
 		// and this buffer storage. All other chunks have no effect
-		if(m_State == WRITING_IDLE && record->GetDataPtr() != NULL || size != record->Length)
+		if(m_State == WRITING_IDLE && (record->GetDataPtr() != NULL || (record->Length > 0 && size != record->Length)))
 		{
-			record->DeleteChunks();
+			// we need to maintain chunk ordering, so fetch the first two chunk IDs.
+			// We should have at least two by this point - glGenBuffers and whatever gave the record
+			// a size before.
+			RDCASSERT(record->NumChunks() >= 2);
+
+			// remove all but the first two chunks
+			while(record->NumChunks() > 2)
+			{
+				Chunk *c = record->GetLastChunk();
+				SAFE_DELETE(c);
+				record->PopChunk();
+			}
+
+			int32_t id2 = record->GetLastChunkID();
+			{
+				Chunk *c = record->GetLastChunk();
+				SAFE_DELETE(c);
+				record->PopChunk();
+			}
+
+			int32_t id1 = record->GetLastChunkID();
+			{
+				Chunk *c = record->GetLastChunk();
+				SAFE_DELETE(c);
+				record->PopChunk();
+			}
+
+			RDCASSERT(!record->HasChunks());
 
 			// add glGenBuffers chunk
 			{
 				SCOPED_SERIALISE_CONTEXT(GEN_BUFFER);
 				Serialise_glGenBuffers(1, &buffer);
-
-				record->AddChunk(scope.Get());
+				
+				record->AddChunk(scope.Get(), id1);
 			}
 
 			// add glBindBuffer chunk
 			{
-				SCOPED_SERIALISE_CONTEXT(GEN_BUFFER);
+				SCOPED_SERIALISE_CONTEXT(BIND_BUFFER);
 				Serialise_glBindBuffer(record->datatype, buffer);
 				
-				record->AddChunk(scope.Get());
+				record->AddChunk(scope.Get(), id2);
 			}
 
 			// we're about to add the buffer data chunk
@@ -426,24 +453,51 @@ void WrappedOpenGL::glBufferData(GLenum target, GLsizeiptr size, const void *dat
 		// data, but we don't support (if it's even possible) querying out size etc.
 		// we need to add only the chunks required - glGenBuffers, glBindBuffer to current target,
 		// and this buffer storage. All other chunks have no effect
-		if(m_State == WRITING_IDLE && record->GetDataPtr() != NULL || size != record->Length)
+		if(m_State == WRITING_IDLE && (record->GetDataPtr() != NULL || (record->Length > 0 && size != record->Length)))
 		{
-			record->DeleteChunks();
+			// we need to maintain chunk ordering, so fetch the first two chunk IDs.
+			// We should have at least two by this point - glGenBuffers and whatever gave the record
+			// a size before.
+			RDCASSERT(record->NumChunks() >= 2);
+
+			// remove all but the first two chunks
+			while(record->NumChunks() > 2)
+			{
+				Chunk *c = record->GetLastChunk();
+				SAFE_DELETE(c);
+				record->PopChunk();
+			}
+
+			int32_t id2 = record->GetLastChunkID();
+			{
+				Chunk *c = record->GetLastChunk();
+				SAFE_DELETE(c);
+				record->PopChunk();
+			}
+
+			int32_t id1 = record->GetLastChunkID();
+			{
+				Chunk *c = record->GetLastChunk();
+				SAFE_DELETE(c);
+				record->PopChunk();
+			}
+
+			RDCASSERT(!record->HasChunks());
 
 			// add glGenBuffers chunk
 			{
 				SCOPED_SERIALISE_CONTEXT(GEN_BUFFER);
 				Serialise_glGenBuffers(1, &buffer);
 				
-				record->AddChunk(scope.Get());
+				record->AddChunk(scope.Get(), id1);
 			}
 
 			// add glBindBuffer chunk
 			{
-				SCOPED_SERIALISE_CONTEXT(GEN_BUFFER);
+				SCOPED_SERIALISE_CONTEXT(BIND_BUFFER);
 				Serialise_glBindBuffer(record->datatype, buffer);
 				
-				record->AddChunk(scope.Get());
+				record->AddChunk(scope.Get(), id2);
 			}
 
 			// we're about to add the buffer data chunk