This kind of element is for modifying landscape rendering. This element has two kinds of child elements, <clear> and <sequence>.
The first one, <clear>, clears the landscape options, setting them back to their defaults; if it has an attribute of "coll", it will clear the sequences for the collection specified in that attribute's value; if not, it will clear all the sequences. However, this command can be followed by commands to set up landscape options, which will then be executed as if no "clear" command had been issued.
The second one, <landscape>, specifies the landscape options themselves. It takes these attributes:
- coll: which collection (mandatory)
- frame: which frame to apply the options to (default: -1, all frames)
- horiz_exp: exponent for power of 2 that is the number of wraparound repeats in the horizontal direction. (default: 1 - two repeats)
- vert_exp: exponent for power of 2 that makes a vertical scaling equal to the scaling produced by the same value of horiz_exp in the horizontal direction. (default: 1 - equal to two horizontal repeats)
- ogl_asprat_exp: exponent for power of 2 that is the ratio of width to height of the part of the texture that OpenGL will use (width is fixed; height can be variable). This part will always be centered in height, and will either include some untextured area or will not include the top and bottom parts. (default: 1 -- height is 1/2 width)
- vert_repeat: whether texture repeats in the vertical direction (default: false -- clamped in the vertical direction; last pixels stretched out)
- azimuth: angle in degrees to rotate the texture leftward relative to the map. This could be useful for aligning landscape features with map ones. (default: 0)