Low frame rate at earth level

[GoogleCodeExporter]

What steps will reproduce the problem?
1. launch webglearth on a relatively slow device (mine is a core 2 duo laptop 
with a radeon X1300 graphics card, 4 go RAM, windows XP 32 bit)
2. When you launch the frame rate is very low (about 3 fps)
3. It is much better when you zoom at city level (20 fps) : 
http://www.webglearth.com/#zoom=10.16;long=1.42580;lat=43.59546

What is the expected output? What do you see instead?
I expect a stable framerate.

What version of the product are you using? On what operating system?
current beta on http://www.webglearth.com

Please provide any additional information below.

Original issue reported on code.google.com by [email protected] on 20 Jan 2011 at 5:49

[GoogleCodeExporter]

Tested under firefox 4 beta 9

Original comment by [email protected] on 20 Jan 2011 at 5:49

[GoogleCodeExporter]

Can you retry in today's nightly build?
http://nightly.mozilla.org/

It has an important optimization in webgl.drawElements.

(Beta 10 does not have it, but beta 11 will)

Original comment by [email protected] on 26 Jan 2011 at 1:05

[GoogleCodeExporter]

The problem is still present under the 26/01/2011 firefox minefield version

Original comment by ahezard on 27 Jan 2011 at 10:44

[GoogleCodeExporter]

ok.
Since we are talking about a performance issue here, the most useful thing to 
do would be to run this in a profiler.

Is this WebGL code using vertex attrib 0 array disabled? That would be 
something to avoid anyway, as it forces implementation to use costly emulation 
tricks (since that is not allowed on desktop OpenGL). Different browsers have 
different approaches there, so Firefox could be more severely performance 
affected, but still, you don't want to do WebGL rendering with vertex attrib 0 
array disabled. If that is the cause of the slowness, then profiles will show 
DoFakeVertexAttrib0.

Original comment by [email protected] on 27 Jan 2011 at 12:49