The use of transform feedback is an effective way to capture vertex shader output. However, there are alternatives that make use of recent features that were introduced in OpenGL. For example, image load/store or shader storage buffer objects could be used. These are writable buffers that can be made available to the shader. Instead of using transform feedback, the vertex shader could write its results directly to a buffer. This might enable you to do everything in a single pass. We use these with compute shaders in Chapter 11, Using Compute Shaders, so look there for examples of their use.