The AA flag is used to select between two different techniques for tree rendering - if you have AA, trees are done using alpha to coverage (aka, the shader doesn't represent 50% transparent as a 50:50 mixture of colors but as a solid surface with 50% holes in it - looks more plausible for representing leaves and needed to run tree shadows, but something in there is apparently isn't supported by your driver.
You can have AA and your working trees by opening
Effects/tree.eff
and commenting out /removing the blocks
- Code: Select all
<technique n="3">
<predicate>
<and>
<property>/sim/rendering/shaders/skydome</property>
<property>/sim/rendering/random-vegetation</property>
<property>/sim/rendering/multi-sample-buffers</property>
<property>/sim/rendering/random-vegetation-shadows</property>
<less-equal>
<value type="float">1.0</value>
<float-property>/sim/rendering/multi-samples</float-property>
</less-equal>
<extension-supported>GL_ARB_shader_objects</extension-supported>
<extension-supported>GL_ARB_shading_language_100</extension-supported>
(...)
lots of stuff
(...)
</technique>
and possibly
- Code: Select all
<technique n="4">
<predicate>
<and>
<property>/sim/rendering/shaders/skydome</property>
<property>/sim/rendering/random-vegetation</property>
<property>/sim/rendering/multi-sample-buffers</property>
<less-equal>
(...)
lots of stuff
(...)
</technique>
Here n=3 does tree shadows and alpha to coverage, n=4 does only alpha to coverage and n=5 does the basic trees for ALS.
Before you mutilate the file, check the tree shadow setting though - maybe all you need to do is not use shadows.
Also, there may be an error message in the console/log file when the trees do not work - if so we'd like to know what it says.
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