Glossary Entry: Palette Swap
Quick Definition
Many programs use graphics that are built around a specific palette (ie, list of colors). By changing the colors in the palette associated with an image, the image itself can be changed drastically with little actual effort on the part of the computer.
However, that's only part of the wizardry at work here: in gaming, a "palette swap" is a new character created by taking an existing character and changing their color palette. Because this is fast and very compact storage-wise, older games often used this method to create lots of "unique" enemies for the player to fight. Modern games sometimes still do this, but it's more common for them to add or remove details (eg, armor, hairstyles, equipment) as well as change the character's colors.
However, that's only part of the wizardry at work here: in gaming, a "palette swap" is a new character created by taking an existing character and changing their color palette. Because this is fast and very compact storage-wise, older games often used this method to create lots of "unique" enemies for the player to fight. Modern games sometimes still do this, but it's more common for them to add or remove details (eg, armor, hairstyles, equipment) as well as change the character's colors.
More Details
In addition to just saving time, many games use palette swapping to alert the player to specific traits of enemies and items. Perhaps the most common example is a color-coded difficulty system; for example, in the first two Legend of Zelda games, enemies were colored an orange-red if they were weak and blue if they were strong. By the by, there is no standard color coding for difficulty, so every game that does this will be using its own system.
Another common usage for palette swapping is to indicate what elements an enemy is strong and weak towards. In this case, colors are usually close to universal as people associate specific colors with specific elements. For example, red enemies are probably going to be fire-based in some way, while blue enemies represent water, and green enemies are likely to be poisonous or even undead.
As for powerups and other items created this way, the usual trend is that red items heal you, blue items recover mana, and green items either recover both or another "energy" supply of some kind. Modern games still continue this color-coding system, but they usually use unique images for each item nowadays.
Another common usage for palette swapping is to indicate what elements an enemy is strong and weak towards. In this case, colors are usually close to universal as people associate specific colors with specific elements. For example, red enemies are probably going to be fire-based in some way, while blue enemies represent water, and green enemies are likely to be poisonous or even undead.
As for powerups and other items created this way, the usual trend is that red items heal you, blue items recover mana, and green items either recover both or another "energy" supply of some kind. Modern games still continue this color-coding system, but they usually use unique images for each item nowadays.
Example
As an example, here are three different potions. It's the same image each time, but the colors are changed to indicate different effects. Since these would be items in a game, you can reasonably assume that they recover health, mana, and something else, based on their colors.
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