3D Realms has released the second dev blog on the upcoming old-school first-person shooter Ion Maiden, written by Voidpoint art lead Aleksander "Cage" Kowalczyk. The article not only describes how creating art for a vintage engine like Build has to be done, but also how the game artist and designers bypass limitations of the 256-color palette system that games in the mid-to-late 1990s used. Here is an excerpt:
Because of all those limits, it was difficult to have enough colors in the palette to depict light color influencing the environment, so most artists went for choosing local colors of the objects they needed for their environment - green for grass, brown for ground or wood, red for blood, gray and blue for metal and skies, etc. Although it sounds like a “coloring book” approach to color, it still left a lot of room for individuality and was used with great results. In Ion Maiden we decided to put more emphasis on different colors, most of them having two variations. We were able to optimise the palette by making some of the darkest shades shared between the colors. This allowed for pretty varied and vibrant environments at the cost of having to work around some color banding - old school dithering or adding extra detail to break up a surface works well!
Despite the limited color count, the developers found ways to show off quite a few cool visual effects. Transparency had to use predefined lookup tables that would tell the game what would be the intermediate between the foreground and background color, additive and multiplicative transparency would be possible using this system as well. Color lighting has found its way to the build engine - it was difficult to do it gradually and subtly, so artists and level designers went for a very colorful, contrasted look, by shifting whole areas into specific colors. We have used this approach in Ion Maiden as well, but we have expanded it with specialised light and shadow sprites using add/multi transparency allowing us to create fluid transitions and more realistic/modern lighting effects! And, all of that can be controlled by the level designer!
All future fans of the game, as well as current and future modders of the Build/EDuke32 engine should give it a read, which can be done right here.