moires runs very slow

[nightpool]

really amazing demo! I tried cloning servo and compiling it myself, but I'm pretty consistently getting 5 fps on the moire demo (on a pretty recent macbook pro).

• I compiled with ./mach build --release
• I cloned moire.html from https://github.com/pcwalton/webrender-demos
• I ran servo with target/release/servo -Z wr-stats -w --resolution=1024x768 --pref dom.mozbrowser.enabled ../webrender-demos/moire.htm (I copied it straight from the demo stream)

this is what I'm seeing: (note the 4 fps)

Interestingly, this seems to be limited to moires. Both spheres and transparent_rects run at ~60fps.

Any thoughts?

[glennw]

I think the moire demo relies on some fixes to the tesselator code landing (which pcwalton has locally). Without this fix the moire demo suffers from a huge amount of needless overdraw. Is that right @pcwalton ?

[dw]

I observed this too -- disabling WebRender causes the moire demo to run much more smoothly on a 2011 era Macbook (HD graphics 3000).

[glennw]

I checked with @pcwalton and this is due to the tesselator being disabled on master at the moment due to a bug - he is working on a fix for this which we should be able to merge soon :)