Landscape Texture Constraints
Note> Some info taken from opennel.org
Introduction
A TileSet is part of the TileBank. There are sevral TileSet in a TileBank. A TileSet is a kind of material (like grass, wood, rock).
This material is divided in small textures (128x128), large textures (256x256) and transition textures (128x128 alpha).
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See File Conversion Graph for details on the build process. |
Small and Large Textures
A tile in the NeL landscape is a bitmap with a size of 128x128. A patch can have 2x2 tiles, 4x4 tiles, 8x8 tiles and 16x16 tiles. But to have bitmaps with a better quality, we can use larges textures (256x256) as 4 tiles.
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A tile transition [layer (2)] is used as an alpha layer between the two tiles [layers (1) & (3)] giving a smoothed transition between different tile sets.
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Results in this tile being displayed.
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Here is the transitions set:
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This is the 48 alpha bitmaps you need to build your bank.
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In fact, you only need to draw 12 alpha bitmaps to fill this bank. The others are computed with a rotation. Here is the 12 alpha bitmaps you really need:
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The batchload function of tile_edit.exe load all the alpha transitions in one shot. To use the batchload function, the alpha bitmaps must have a name like wood_alpha00.tga, wood_alpha01.tga. The number of a transition tile is given by its position in the previous set. The first (left, top) is number 00, and so on, first to the right then to the bottom.
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From Old Wiki
Creating the textures is the trickiest part of creating the tile bank. There are tiling restrictions outlined below that make it more difficult to create the textures. In addition you need to avoid any extremes of light or dark in the tiles so patterns are not obvious when you tile them together.
The tile format MUST be an uncompressed TGA image. Two sizes are 128x128 and 256x256 pixels, you can use either 24 or 32 bit images.
Most importantly the border of an image must be mapped as below, the left and right edges MUST be EXACTLY the same, the top and bottom edges MUST be EXACTLY the same, the entire border ( all four edges ) MUST be the same as EVERY other tile in that TileSet.
If you have a TileSet for autumn forest grass type b then any grass tile in this set must have EXACTLY the same border.
A Border is a band one pixel wide that follows the edge of the ENTIRE image.
The 256x256 tiles MUST have two of each 128x128 border edge side by side as shown in the images below. This enables 256x256 tiles to link with 128x128 tiles seamlessly.
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Naming Conventions
TGA tile files should follow this basic naming convention to allow them to work with the batch load functions and possibly help with ASyncTextureLoading? later on.
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Here is an example of the correct order the different transition tiles should be loaded in.
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The batch load function of tile_edit.exe loads all the alpha transitions in one shot. and adds the rotation variations automatically. To use the batch load function, the alpha bitmaps must have the naming convention discussed above. The number of a transition tile is given by its position in the previous set. The first is number 00.
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