Rendering landscapes

From CCoWS Wiki
Jump to: navigation, search

The Tarsier rendering system typically constructs the basic appearance of a landscape using the following elements:

1. The terrain elevation. This a 2D surface usually based on a DEM or some bathymetry data, or a hybrid of the two. The height of the surface is based on a terrain raster (translated to a terrain object), and the color is based on another raster (see 2 below). It may be drawn with a basic texture, such as sagebrush, or a sandy ocean bottom.

2. The terrain color. This is derived from a raster that dictates what color to drawn the terrain in - using either a true-color color scheme getting RGB values from the raster itself, or false color scheme indexed by the raster values.

3. Symbols. Objects that are distributed in relation to the terrain, like trees or kelp, can be drawn via a 'symbol raster'. This raster maps what type of symbols should be drawn in what areas, and Tarsier interprets this raster placing symbols in a predictable random pattern usually at densities higher than the resolution of the raster itself.

4. A cover raster. Since the desired number of symbols could number in the trillions for large landscapes, a trick can be employed to draw the symbols using a transparent 'cover texture' that floats above the landscape. The settings can be adjusted to fade from the real symbols to the cover-raster at a certain distance, since the cover raster looks fake when viewed close up.