# Variable Wind

RenderWorld has the ability to change the ambient wind speed and direction with time. In this example, rather than specifying a wind speed and direction, we give a file which has these as a function of time. Specifically, we start with the wind blowing into 10 degrees (nearly due north) at 4 meters / second. It then increases to 10 m/s over the next 5 seconds. In the following 5 seconds in holds the same speed, but swings around to blow westward (90 degrees).

  `RenderWorld_data_file ocean 5 5`
  `n_points_x` `512` `1`
  `n_points_y` `512` `1`
  `dx` `1.0`
  `dy` `1.0`
  `spectrum_file` `spec1.dat`
  `generate_file` `yes`
  `random_seed` `1451`
  `end`
  `number_aux_oceans` `0`
  `number_disturbances` `0`
  `box_depth 20.`
  `reference_time` `0`
  `surface_type` `round`
  `radius` `6371230`
  `max_distance` `100`
  `double_distance` `70`
  `wind_type` `yes`
  `wind_file` `wind.dat`
  `waves` `yes`
  `water_type` `3`
  `external_exact` `no`
  `glitter` `no`
  `whitecaps` `no`
  `textures no`
  `sunbeams no`
  `exclude_items no`
  `number_of_bands 3`
  `band_ids 1 2 3`
  `index_of_refraction` `1.34 1.34 1.34`
  `end`

The wind file wind.dat referenced in the disturbance portion of the ocean file has the following form:

           number_of_times 3
           time   speed    wind_angle
           0      4        10
           5      10       10
           10     10       90

Contents