The purpose of this article is to share some knowledge and information about an important part of the texture creation process for game development. I hope this information can enable or inspire you to improve your own process, increase quality, and ultimately save you time and money.
Before beginning production on any art related assets for your game, I highly recommend establishing texture creation guidelines in the form of a texture guide. For any game requiring textures, this should be considered a crucial step… unless of course you enjoy sacrificing time, money, and quality.
A good texture guide defines the pipeline, creation rules, and how textures should look and be used within your game. While a texture guide can be a great reference point and tool for art direction to help maintain quality and consistency, it is valuable to everyone on the team, not just artists. For example, there could be some specific design rules outlined in the texture guide such as interactive doors using green tones, or the color red being used to identify explosive objects.
The texture guide can be represented in print or digital form (such as wiki, html, pdf, etc.), but it needs to be easily accessible to everyone involved with the project. For most situations, I recommend a digital form such as a wiki page, because it tends to be the easiest to update and share with others. In some cases, a PDF file or a JPG can also work very well. In some cases, it can be beneficial to have multiple texture guides, such as one for characters, one for props, one for environments, and so on. Regardless of how many guides there are, they should all follow a consistent format (all on the wiki, or all PDF files for example).
The amount of detail in a texture guide should depend on the team’s needs. How large will the art team be? How experienced are they? Are there plans to outsource any of the work? If so, will it be to a location where there could be cultural, language, or time differences? Translation may also be needed in some cases to accommodate team members. Spending the extra time to provide proper details in the texture guide can easily save your project hundreds of hours in the long run.
Regarding content, the texture guide should provide a clear, visual explanation as to how textures should look and be created for the game. At a bare minimum, the following topics should be covered to some degree:
Defining a style for the textures may seem like an obvious component to include in a texture guide, but it can actually be quite tricky to get right. Providing incomplete or unclear information can lead to inconsistencies and confusion for artists, which can affect the game’s quality and development costs.
There are many different styles to choose from. Photo-realism, cartoony, painterly, etc. There are variations within those styles as well, so clarity is important. Disney’s The Lion King and The Simpsons can be described as ‘cartoony’, but their styles are obviously quite different. If the style is influenced by another artist (or even several artists), it should be explained how and why, with some examples provided.
One obvious and important way to communicate the texture style is through clear visual examples in the texture guide, but the most effective way is with a ‘visual target’. A visual target is an in-game, playable area that showcases what the final art should look like. It encompasses all elements of the art (modeling, texturing, shaders, animation, VFX, lighting, etc.), and is the most useful tool to ensure everyone is on the same page with the texture style.
Color helps to define the mood, direction and even functionality. With textures, it’s important to understand how a texture will look in-game once lighting and shaders have been applied to it. There can be a substantial difference between what an artist sees in the actual game on a screen vs. what they see in a paint program on their computer’s monitor.
A color scheme should be chosen (complementary, monochromatic, split-complementary, etc.), and a palette defined, to help achieve color consistency and tonal balance. In some cases, a game may use several palettes for different environments, or even types of objects (such as a specific color to define some gameplay functionality). Regardless, all this information should be communicated in the texture guide.
Effective storytelling is one of several reasons a player can become immersed in a game. The visuals play an important role in this, especially the textures. For example, if a game takes place in a post apocalyptic setting, the textures could convey this through weathering, damage, and aging, while the colors might be darker and more dreary to set the mood.
In addition to the high-level story or setting, an individual texture should have its own story. What materials it is made of? How old is it? Did anything interesting happen to it recently (eg. graffiti, scratches, blood stains, etc.). How does it relate to the setting and larger story? All of this information should be conveyed within the texture guide to help with consistency.
Consistency is very important when telling a story with visuals because a player will subconsciously notice when something is ‘off’. This can break the immersion and potentially disengage the player from a game altogether.
A texel is a pixel of a texture. Texel density describes how many texels cover a certain distance. For example: In the game Minecraft, each side of a 1 meter block has a 16×16 pixel portion of a texture mapped to it. This means that the texel density of those blocks is simply 16×16 pixels per meter. Other games such as Uncharted 2 use a higher resolution ratio of 512×512 per 3 meters.
An optimal texel density helps maintain visual consistency, performance, and texture memory usage. To define the optimal texel density for a game, the following questions must be collectively taken into consideration:
Does the style or a performance requirement dictate texture resolution?
Minecraft is a perfect example where both the style and performance choice was made to use lower resolution textures. This gave the game a unique ‘retro’ look, while also allowing it to run efficiently on a large range of hardware.
What is the game’s output resolution?
The resolution can determine a game’s texel density. The higher the resolution, the higher texel density you will need (unless there is a conscious choice to make lower resolution textures). A game being created for a variety of platforms (such as tablets, smart phones, consoles, and computers), can complicate things. If that is the case, it may be wise to have platform-specific texture rules to automate the process of re-sizing texture resolutions for these platforms. This never gives the best quality output, but the production time trade-off is well worth it when dealing with large amounts of textures and multiple platforms.
How close will the player get to the texture in-game?
Understanding how the player sees the textures in the actual game is very important. Some textures may be further away, while others may be closer to the in-game camera. It’s important to identify these assets with some basic rules and categorizations in the texture guide to streamline production. For example, an asset may be identified as a ‘background object’ which might also have a texel density rule of 32×32 pixels per meter. In this case, the artist would know to not create a texture with too much detail for that asset.
How does the game engine handle mipmapping?
Most game engines will cross fade between mipmap levels of a texture as the player gets closer or further away from it. It is important to understand this because the engine will always render the optimal resolution it needs and never anything higher (though this can be overridden through code). Using a texture with a higher resolution than the game needs simply means that the originally authored texture would never be seen at its fullest and texture memory would be wasted needlessly.
The pipeline is probably the most critical element of the texture creation process. A good, well defined pipeline increases productivity, iteration time, consistency, and quality. This is also the area where artists tend to make the most costly mistakes during production due to incomplete, unclear, or undefined guidelines. It is for this reason that the pipeline portion of the texture guide should be the largest and most descriptive of all the sections. It should provide a full breakdown of how to author textures completely from the very start, to the point where it is in-game on a 3d model. This includes all texture types used in the game (diffuse, specular, normal maps, reflection maps, etc.).
The following is a list of pipeline topics that should be thoroughly explained in the texture guide:
- What software, tools or plug-ins should be used?
- Are there special instructions for installing, setting them up, or using them?
- What file format(s) should be used for raw and exported files?
- What are the name conventions, rules, and folder locations?
- Are there any shader settings that need to be considered or used?
- Finally, what are the complete steps for creating a texture and seeing it in-game (A to Z)?
The last important aspect to any good texture guide are example assets. The famous expression ‘a picture is worth a thousand words’ is especially true with a texture guide, because it is the clearest way of explaining and demonstrating quality expectations to the team.
Example assets can be images accompanying your texture guide, but it is even more effective to have actual texture examples demonstrated within a visual target. Doing this provides multiple benefits:
- reference examples for the style, color, and story
- real-time visual understanding of how the textures react in the game with proper lighting, shaders, and VFX
- a tool for art directors to use and refer to when critiquing and providing feedback
- on the other hand, it also keeps art directors ‘honest’ and prevents them from redefining the art direction on-the-fly
- early proof of concept for game design elements (eg. the use of color to define functionality)
- demonstration of texel density, file formats and setups, name conventions, folder locations, and shader settings
In summary, while many games have been created without texture guides, it is important to understand the risks and costs of not using one. This importance exponentially grows with larger team sizes and complex pipelines. Regardless size, it is always helpful to acquire feedback to ensure that the guide is clear and understood by everyone on the team.
The benefits of taking the time to create an effective texture guide have been outlined above, but there is one last important benefit to consider. Once you have one texture guide, it becomes much easier and faster to adapt an existing texture guide to a new style and game, making it beneficial and even cheaper for future projects as well.
Here are some great examples to hopefully inspire you to create texture guides for your own game: