Created attachment 224 [details] a startable java program. the two buffers should contain the same values. but they does not version: last from git I uploaded a simple float buffer to opengl via glBufferData and then downloaded the buffer via glMapBuffer. The result do not contain the data of the uploaded buffer. I am new to JOGL and OpenGL3. Maybe I am wrong but it works well in a c++ exsample. I attach an example java file to reproduce the problem.
You have chosen to not feed the data using glBufferData(..) using a non NIO buffer and without the native order. You have to set the ByteBuffer's order to native: verticiesBB.order(ByteOrder.nativeOrder()); before pushing data to it and passing it to the GPU, since the resulting NIO Buffer is of course in native order. You could also use our NIO factory Buffers: ByteBuffer verticiesBB = Buffers.newDirectByteBuffer(4*9); which always uses the native order. It works this way. Maybe a good candidate for a glMapBuffer unit test ?