The detail you include when creating textures should be proportionate to the visual impact of that detail. Make sure that you only create details that can be seen.
Phone screens are small, therefore fine-grained detail is not visible. Take this into account when creating textures. For example, you do not need a 4K texture with lots of details for a chair that is barely visible in the corner of the room.
The following screenshot shows an example. The small 256x256 pixel texture on the left has a low level of detail to be used on soldier characters. The larger image on the right shows the entire scene, and shows that the low level of texture detail is sufficient for the required amount of detail:
In certain cases, you need to exaggerate and highlight edges and shading to improve shape readability. Because mobile platforms generally use smaller textures, it might be hard to capture all of the detail that is needed within this small texture.
Use fewer textures and bake in any extra details into one texture. This is important because:
- Phone screens are small, and some details are better to be baked onto the diffuse texture itself to make sure that those details are visible.
- Elements like ambient occlusion and small specular highlights can be baked in and then added to the diffuse texture.
This approach means that you do not have to rely too much on shader and engine features to get specular and ambient occlusion.
The following screenshot shows an example of details that have been baked into a texture, for example the highlights on roof tiles:
When possible, use grayscale textures that allow color tinting in the shader. This saves texture memory at the cost of creating a custom shader to perform the tinting.
Be selective with this technique, because not all objects look good using this method. It is easier to apply this technique to an object that has a uniform, or similar, color.
You can also use RGB masks and then apply textures that are based on the color range of the mask to achieve this effect.
The following image shows an example of a grayscale texture that is being applied to a tinted pillar: