A few more fixes related to the previous commit.

common/gal/opengl/cached_container.cpp

@@ -413,7 +413,7 @@ bool CACHED_CONTAINER::defragmentResize( unsigned int aNewSize )
     assert( IsMapped() );
 
     wxLogTrace( "GAL_CACHED_CONTAINER",
-            wxT( "Resizing container from %d to %d" ), m_currentSize, aNewSize );
+            wxT( "Resizing & defragmenting container from %d to %d" ), m_currentSize, aNewSize );
 
     // No shrinking if we cannot fit all the data
     if( aNewSize < m_currentSize && usedSpace() > aNewSize )
@@ -426,11 +426,22 @@ bool CACHED_CONTAINER::defragmentResize( unsigned int aNewSize )
 
     GLuint newBuffer;
 
+    // glCopyBufferSubData requires a buffer to be unmapped
+    glUnmapBuffer( GL_ARRAY_BUFFER );
+
+    // Create the destination buffer
     glGenBuffers( 1, &newBuffer );
-    glBindBuffer( GL_COPY_WRITE_BUFFER, newBuffer );
-    glBufferData( GL_COPY_WRITE_BUFFER, aNewSize * VertexSize, NULL, GL_DYNAMIC_DRAW );
-    glBindBuffer( GL_ARRAY_BUFFER, m_glBufferHandle );
-    checkGlError( "resizing vertex buffer" );
+
+    // It would be best to use GL_COPY_WRITE_BUFFER here,
+    // but it is not available everywhere
+#ifdef __WXDEBUG__
+    GLint eaBuffer = -1;
+    glGetIntegerv( GL_ELEMENT_ARRAY_BUFFER_BINDING, &eaBuffer );
+    assert( eaBuffer == 0 );
+#endif /* __WXDEBUG__ */
+    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, newBuffer );
+    glBufferData( GL_ELEMENT_ARRAY_BUFFER, aNewSize * VertexSize, NULL, GL_DYNAMIC_DRAW );
+    checkGlError( "creating buffer during defragmentation" );
 
     // Special case: the container is either already defragmented or filled up to its capacity,
     // so we just resize it and move the current data
@@ -439,7 +450,7 @@ bool CACHED_CONTAINER::defragmentResize( unsigned int aNewSize )
     {
         assert( aNewSize != m_currentSize );
 
-        glCopyBufferSubData( GL_ARRAY_BUFFER, GL_COPY_WRITE_BUFFER,
+        glCopyBufferSubData( GL_ARRAY_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
                 0, 0, usedSpace() * VertexSize );
     }
     else
@@ -454,7 +465,7 @@ bool CACHED_CONTAINER::defragmentResize( unsigned int aNewSize )
             int itemSize      = item->GetSize();
 
             // Move an item to the new container
-            glCopyBufferSubData( GL_ARRAY_BUFFER, GL_COPY_WRITE_BUFFER,
+            glCopyBufferSubData( GL_ARRAY_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
                     itemOffset * VertexSize, newOffset * VertexSize, itemSize * VertexSize );
 
             // Update new offset
@@ -466,15 +477,18 @@ bool CACHED_CONTAINER::defragmentResize( unsigned int aNewSize )
     }
 
     // Cleanup
-    glBindBuffer( GL_COPY_WRITE_BUFFER, 0 );
+    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, 0 );
     glBindBuffer( GL_ARRAY_BUFFER, 0 );
+    // Previously we have unmapped the array buffer, now when it is also
+    // unbound, it may be officially marked as unmapped
+    m_isMapped = false;
     glDeleteBuffers( 1, &m_glBufferHandle );
 
     // Switch to the new vertex buffer
     m_glBufferHandle = newBuffer;
     glBindBuffer( GL_ARRAY_BUFFER, m_glBufferHandle );
-    checkGlError( "switching buffers during defragmentation" );
     Map();
+    checkGlError( "switching buffers during defragmentation" );
 
 #ifdef __WXDEBUG__
     prof_end( &totalTime );