3.1 Graphics Basics

As we’ve seen before, graphics in Age of Empires prior to Definitive Edition come in .slp files, either by themselves in the “drs” folder of the mod or compressed into a .drs file. To visualize them, we use Turtle Pack, but that program offers very little features in terms of edditing and, for the most part we use SLX Studio. You can find links to both programs in the introduction.

3.1.1 Turtle Pack​

If you open an .slp file with turtle pack, you’ll see all its frames and for each frame, a couple of elements:

• The Anchor, that control where the graphic is displayed, to ensure that a unit’s graphic coincides with its phisical position in the game.
• The Selection mask, the overlay that appears when a unit goes behind a building.
• You can change the player color of the unit.

In TurtlePack you can move the anchor of the graphics, reorder frames, extract frames as bmp files, load bmp files as new frames and delete frames.

3.1.2 SLX Studio​

If you open an slp file with SLX Studio (by importing or drag-and-drop), you’ll see that each frame is actually comprised of two images: the actual graphic and the data graphic, that stores all the information of the graphic with different colors:

• The background, in pink, that codes which pixels should not be shown in game.
• The shadow, in red, that codes which pixels should be painted gray in game, regardless, of what appears in the actual graphic.
• The outline, in blue, identical to the selection mask.
• The player color, in green, that codes which pixels change color with the player.

SLX Studio offers a ton of features to modify the graphics, the frames, and generate graphics in different formats. We’ll see some of the features as we go over applications.

3.1.3 The Color Palette​

One concept that may confuse people at first is the fact that Age of Empires doesn’t allow for every color to be displayed in the game. Every graphic can only use 256 colors that are coded in the palette. The following is the main palette in the game, used for painting units, buildings, terrain, trees… Things like the main menu or the loading screens have different palettes.

Palettes are stored in interfac.drs, in the data folder of the game. You could modify it and have a different version for a mod but I don’t know of any examples.

The issue with palettes is that sometimes, when you are adding new graphics, either created by you or from Definitive Edition which allows more colors, you may notice that the generated slp has some colors different from the original bmp files you were using. This is because SLX studio will convert a bmp file (potentially coded in 24 bit colors) to the palette, looking for the closest valid colors.