syncing mapped buffers using flush

syncing_buffers.java

//map buffer with GL_MAP_FLUSH_EXPLICIT_BIT

waitBuffer(gl4, rbWriteIndex); 

perMeshPointer.position(rbAlignment * rbWriteIndex); 
perMeshPointer.asFloatBuffer().put(perMesh[i].toFa()); 
perMeshPointer.rewind();

gl4.glFlushMappedBufferRange(GL_UNIFORM_BUFFER, rbAlignment * rbWriteIndex, rbAlignment);
gl4.glBindBufferRange(GL_UNIFORM_BUFFER, 
                    Semantic.Uniform.PER_MESH, 
                    bufferName.get(Buffer.PER_MESH), 
                    rbAlignment * rbWriteIndex, 
                    rbAlignment 
            );
/* do render*/ 
lockBuffer(gl4, rbWriteIndex);
rbWriteIndex = (rbWriteIndex + 1) % rbMax;