|Scrolling Game Development Kit UI Help||Up to Edit Maps Dialog|
This is part of a series of pages describing the Edit Maps Dialog. This page describes the Layers tab.
The map layers are where the main content of a map is really stored. Each Layer object contains an array of tiles which define the contents of an entire area covering the map. Multiple layers can be defined to represent foreground and background layers of the map, and they can scroll at different speeds. The size of the layer (fundamentally defined in tiles) is determined entirely by the map its contained in. This size is calculated when the layer is created or updated. A lower scroll rate, for instance, will result in a layer requiring fewer tiles than a similar layer with a higher scroll rate. In order for the layer to have content accross the entire area of a map, it's necessary for a faster scrolling layer to have more content.
To create a layer, you must first select a map which will own the layer. Then enter a name for the layer (which must be unique in the space of layer names for this map). Select a tileset which the layer uses. The tiles of each layer are restricted to the 256 (maximum) tiles contained in a tileset. (If you need more tiles you can add another transparent layer with the same scroll rate using a different tileset.) The X scroll rate and Y scroll rate indicate how fast the layer scrolls relative to the map. It's a good idea for your main layer (where the player is and probably where all the action takes place) to have values of 1 here. Any layer that scrolls slower than this would have values between 0 and 1, and any layer than scrolls faster would have a value greater than 1. Don't get carried away with scroll rates. Remember that a faster scrolling layer requires more tiles. If you have a map that's 16,000 pixels x 16,000 pixels, and that layer's tileset uses tiles that are 16x16 pixels, a layer that scrolls at a rate of 1,1 would require about 1 MB while a layer that scrolls at a rate of 2,2 would require about 4 MB.
The last option to select for a layer is the "Transparent layer" checkbox. You should always have exactly one layer that is not transparent, and the remainder of the layers should have this box checked. And of course, if you want to see all these layers, the transparent layers should all be on top of the non-transparent layer.
The "Screen Depth" here is not a persistent property. It is only used to determine what video mode to use when the Edit button is clicked. The Edit button will display The Full Screen Map Editor. (If you only want to view a layer, or want to view it alone or scaled, you can use the Quick View button to display the Layer Quick View window.) Use the "Update Layer" button whenever you have clicked on a layer and made changes to its properties. All layer information and parameters are stored within the MAP file.