Non-zero stream outputs can't be used in fragment shaders.
According to ARB_gpu_shader5 spec, "Geometry Shader Vertex Streams"
section:
"The primitives emitted to all vertex streams are passed to the transform
feedback stage to be captured and written to buffer objects in the manner
specified by the transform feedback state. The primitives emitted to all
streams but stream zero are discarded after transform feedback.
Primitives emitted to stream zero are passed to subsequent pipeline stages
for clipping, rasterization, and subsequent fragment processing."
Thus, it is an error trying to use a GS output as FS input that was
emitted through non-zero stream.
Affects:
KHR-GL45.enhanced_layouts.xfb_vertex_streams
Components: OpenGL
VK-GL-CTS issue: 557
Change-Id: I008c929b600905b1f3eb27a05753c8c75bf82ac5