From 1d087cc5c2cb882424e7d8022ae16740192f36b2 Mon Sep 17 00:00:00 2001
From: Alex Szpakowski <slime73@gmail.com>
Date: Tue, 21 Jul 2020 21:56:47 -0300
Subject: [PATCH] Fix Mesh/Buffer:flush uploading more data than it needs to,
 sometimes.

---
 src/modules/graphics/opengl/Buffer.cpp | 16 ++++++++++++++--
 src/modules/graphics/opengl/Buffer.h   |  1 +
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/modules/graphics/opengl/Buffer.cpp b/src/modules/graphics/opengl/Buffer.cpp
index 3fd4beaed..2b17dc121 100644
--- a/src/modules/graphics/opengl/Buffer.cpp
+++ b/src/modules/graphics/opengl/Buffer.cpp
@@ -112,6 +112,7 @@ void *Buffer::map()
 
 	modifiedOffset = 0;
 	modifiedSize = 0;
+	isMappedDataModified = false;
 
 	return memoryMap;
 }
@@ -149,8 +150,13 @@ void Buffer::unmap()
 	if (!mapped)
 		return;
 
+	mapped = false;
+
 	if ((mapFlags & MAP_EXPLICIT_RANGE_MODIFY) != 0)
 	{
+		if (!isMappedDataModified)
+			return;
+
 		modifiedOffset = std::min(modifiedOffset, getSize() - 1);
 		modifiedSize = std::min(modifiedSize, getSize() - modifiedOffset);
 	}
@@ -184,8 +190,6 @@ void Buffer::unmap()
 
 	modifiedOffset = 0;
 	modifiedSize = 0;
-
-	mapped = false;
 }
 
 void Buffer::setMappedRangeModified(size_t offset, size_t modifiedsize)
@@ -193,6 +197,14 @@ void Buffer::setMappedRangeModified(size_t offset, size_t modifiedsize)
 	if (!mapped || !(mapFlags & MAP_EXPLICIT_RANGE_MODIFY))
 		return;
 
+	if (!isMappedDataModified)
+	{
+		modifiedOffset = offset;
+		modifiedSize = size;
+		isMappedDataModified = true;
+		return;
+	}
+
 	// We're being conservative right now by internally marking the whole range
 	// from the start of section a to the end of section b as modified if both
 	// a and b are marked as modified.
diff --git a/src/modules/graphics/opengl/Buffer.h b/src/modules/graphics/opengl/Buffer.h
index e3c089ebc..64fde2f3c 100644
--- a/src/modules/graphics/opengl/Buffer.h
+++ b/src/modules/graphics/opengl/Buffer.h
@@ -75,6 +75,7 @@ private:
 
 	size_t modifiedOffset = 0;
 	size_t modifiedSize = 0;
+	bool isMappedDataModified = false;
 
 }; // Buffer