It's pretty easy to fix the scaling issues with buildings in hon.
There was once a patch which activated pbo-support and fixed this issue but only one part of that patch has made it into the mesa-tree.
I looked up the patch and edited it to apply correctly on current git:
The discussion on the mailinglist can be found here:
Can someone push this patch to Xorg edgers?
The patch enables features which aren't fully supported yet in the driver. Whether or not a particular app uses them comes down to luck of the draw.
I don't remember everything off hand. Texture arrays and some glsl instructions among other things. Richard or Andre would know better.
Omigod Omigod Omigod.
r300g is finally able to run HoN Ingame, without crashing.
Unfortunately it doesn't display player or building models yet, but still it's getting really close now.
Here are two screenshots:
Performance appears to be great, and even some advanced features like Refractions are working, as can be seen in the screenshots.
It's running now because somebody put in dummy shaders so it doesn't crash when it hits the unimplemented stuff. As you can see there seems to be a lot of stuff that needs to be done still.