Wind shader configuration and tuning

The Runtime SDK wind shader functions take SWindInputSdk.m_sOptions (of type SWindOptionsSdk) as part of their input. Explanations for each function are as follows:

Function	Description
m_bDoShared	Corresponds to the Global Motion settings in the Modeler. When disabled, the global motion contribution is skipped.
m_bDoBranch1	Corresponds to the Branch Motion 1 settings in the Modeler. When disabled, the branch motion contribution is skipped.
m_bDoBranch2	Corresponds to the Branch Motion 2 settings in the Modeler. When disabled, the branch motion contribution is skipped. Branch wind can be the most expensive wind component in a SpeedTree vertex shader, so enabling the second level only for the models that need it can help with optimization.
m_bDoRipple	Corresponds to the Frond Motion settings in the Modeler. When disabled, the frond rippling behavior is skipped.
m_bDoShimmer	Corresponds to the Adjust lighting option in the Frond Motion settings in the Modeler. When disabled, this single effect will be skipped.
m_bLodFade	Unused by our sample shader but can be used to have more detailed wind effects up close and gradually transition to simpler effects like global motion only.
m_fWindIndependence	Controls how synchronized two wind instances will be. At 0.0, two instances will exhibit identical wind behavior, whereas 1.0 is no synchronization.

The following shows the corresponding wind editor settings in the Modeler:

Optimization

One technique for measuring the impact each option might have on performance is to try compiling the sample shaders in [SDK]/SampleForest/Shaders/ in dx11 mode to see how the output instruction count varies. See Shader Compilation for more information.