From 6c850fdc98712b68517112960324b020bfaf0d56 Mon Sep 17 00:00:00 2001
From: vrld <vrld@vrld.org>
Date: Mon, 15 Oct 2012 17:13:08 +0200
Subject: [PATCH] Possibly (code in issue does not fail on my machine) fix
 #486. Please test.

---
 src/modules/graphics/opengl/VertexBuffer.cpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/modules/graphics/opengl/VertexBuffer.cpp b/src/modules/graphics/opengl/VertexBuffer.cpp
index 720603bb0..098f3c883 100644
--- a/src/modules/graphics/opengl/VertexBuffer.cpp
+++ b/src/modules/graphics/opengl/VertexBuffer.cpp
@@ -139,9 +139,12 @@ void *VBO::map()
 
 void VBO::unmap()
 {
-	glBufferSubDataARB(getTarget(), 0, getSize(), mapped);
-	free(mapped);
-	mapped = 0;
+	if (mapped)
+	{
+		glBufferSubDataARB(getTarget(), 0, getSize(), mapped);
+		free(mapped);
+		mapped = 0;
+	}
 }
 
 void VBO::bind()