code: func (a *arrayBufferLayout) enable(context *context, program program) {
  	for i := range a.parts {
  		context.enableVertexAttribArray(program, i)
  	}
  	total := a.totalBytes()
  	offset := 0
  	for i, p := range a.parts {
  		context.vertexAttribPointer(program, i, p.num, float, total, offset)
  		offset += float.SizeInBytes() * p.num
  	}
  }
docs: // enable binds the array buffer the given program to use the array buffer.