I am using the tessellation shader stage to increase the density of triangles close to camera. Thereby when the camera is too close to a triangle, so that the maximum tessellation is not high enough, it should store the tessellated parts to the transform feedback buffer. Then, in the next render pass, these tessellated parts should be tessellated again to ensure a good triangle to pixel ratio.
To achieve that, the idea is to only render the well tessellated triangles, and only store the "not enough tessellated" triangles to the transform feedback buffer AND NOT render them.
As far as I understood, this behavior is not possible, because all vertices which pass the final Vertex Processing shader stage will be stored to the feedback buffer.
So first: Is there a way to enable / disable the transform feedback writing inside GLSL?
second: And also the other way around: stop rendering but writing to the buffer?
for the last case (stop rendering but writing) the fragment shader could discard these triangles... A better way would be to stop rasterize them... (performance)