$treesway

Tree with treesway on de_lake in CS:GO (click to preview).

$treesway is a material shader parameter for the VertexLitGeneric shader available in all Source games since Left 4 Dead 2. (also in ) In , it can also be used for UnlitGeneric. $treesway morphs the vertices of a mesh with a given material around using the parameters of an env_wind entity to give the appearance of tree leaves and foilage blowing in the wind. The subparameters of $treesway determine how much the env_wind entity should affect the morphing, and all of them (except $treeswaystatic) must be specified in order for the effect to work properly. This shader parameter assumes any model using it is facing upwards.

Note:This shader parameter is disabled by default in the SDK. It can re-enabled by modding.

Warning:Due to the way bumped lighting is calculated, $treesway will not sway materials which use $bumpmap.

Bug:

• This shader parameter does not work with $detailtexturetransform.
• In , using a shadow-casting projected texture on materials with this parameter will cause flickering. As a workaround, try to keep trees away from where player flashlights can reach. $halflambert may also partially fix the issue.
• In , using a shadow-casting projected texture will cause shadows not reacting to $treesway, shadows don't move, expect in .

Todo: What about $singlepassflashlight and $flashlightnolambert?

  [todo tested in ?]

Important:While $TreeSway can be used to animate a prop_static, lightmap shadows casted by swaying static props will remain static.
If CSM is unavailable, consider using a prop_dynamic instead. This can be combined with an animation containing more realistic pre-baked wind physics than can be achieved with $treesway.
As prop_dynamic cannot be lit by VRAD per-vertex, it may be desirable to use a pre-baked $lightmap (if available) in such situations, to restore some ambient lighting quality.

Parameters

$treesway $treeswayheight $treeswaystartheight $treeswayradius $treeswaystartradius $treeswayspeed $treeswaystrength $treeswayscrumblespeed $treeswayscrumblestrength $treeswayscrumblefrequency $treeswayfalloffexp $treeswayscrumblefalloffexp $treeswayspeedhighwindmultipler $treeswayspeedlerpstart $treeswayspeedlerpend $treeswaystatic $treeswaystaticvalues

External links

https://gamebanana.com/tuts/12924 - How to achieve a similar effect without $treeSway, on all source engine games. Alternatively, use an animated prop_dynamic, for a more realistic (but more expensive) effect.