Mapbox’s Maps SDK allows developers to create custom styling for buildings in their Unity projects.
Mapbox’s Maps SDK allows developers to create custom styling for buildings in their Unity projects. Custom styles can include user-defined architectural feature proportions, textures, and colors. Custom styles are comprised of three different building blocks:
- AtlasInfo files
- MapboxStyles materials
- Scriptable Palettes
Create an AtlasInfo file
AtlasInfo files contain user-defined data that tells the Maps SDK how to organize, partition and assign sections of a texture atlas to procedurally generated buildings. They inherit from Unity’s scriptable object class, which means they can be saved in a Unity project and used in multiple scenes.
The AtlasInfo class inherits from Unity’s scriptable object class. Users can use the default Atlas Info file, or create their own by doing the following:
- Right click or go to the Assets menu and navigate to
Create > Mapbox > AtlasInfoto create an AtlasInfo file.
- Click Textures.
- Change the Size to 1.
- Click Element 0 to view the parameters.
- Repeat steps 1-4 for Roofs.
Textures: Contains a public list of texture sections for building facades.
Roofs: Contains a public list of texture sections for building roofs.
Note that textures and roofs can have sections that overlap in UV space. This is useful, as facade and roof textures can be packed either in one Atlas texture or multiple, as roof and facade geometry can use different materials.
Texture Rect: Position and size of texture section in UV space
- X: Position of the bottom left corner of the texture section in UV space.
- Y: Position of the bottom left corner of the texture section in UV space.
- W: Width of the texture section in UV space.
- H: Height of the texture section in UV space.
Mid floor count: Number of mid floors to define in texture space. Mid floors will repeat as required to fill a given building’s height. If you set the mid floor count to 1, a single floor will be redrawn repeatedly. Mid floor counts of greater than 1 will result in a series of floors being redrawn in a repeated sequence.
Column count: Number of columns to define in texture space. Columns will be repeated as necessary.
Top Section ratio: Height ratio of the top floor in the section. So if a section has 8 floors (including ground and top floors) and they are all equal height, this should be 1/8.
Bottom Section ratio: Height ratio of the ground floor in the section. So if the section has 8 floor (including ground and top floors) and they are all equal height, this should be 1/8.
Preferred Edge Section Length: Ideal wall length. The mesh generation setting will cut down long wall segments to smaller chunks of this length and chosen texture section will be applied to each separately. This setting doesn’t effect uv mapping directly.
Floor Height: Single mid floor height. Even if the texture has a big mid segment that consists of multiple floors, this value is a single one of them. This is a mesh generation setting, and doesn’t effect uv mapping directly.
First Floor Height: Ground floor height. This is a mesh generation setting, and doesn’t effect uv mapping directly.
Top Floor Height: This is a mesh generation setting, and doesn’t effect uv mapping directly.
Export an AtlasInfo file as a savable template texture
Data defined in an AtlasInfo file can be exported as a savable template texture. This texture can then be opened in an image editing program such as Adobe Photoshop or Illustrator, and used as a reference layer for constructing a texture atlas that conforms to the structure defined in the AtlasInfo.
- From the top menu, go to
Mapbox > Atlas Template Generator.
- In the Mapbox Atlas Template Generator window, drag an AtlasInfo file into the Atlas info field, shown below.
- Select what AtlasInfo data to render to the texture by checking Create Facades and/or Create Roofs
- Specify a Texture resolution. The default is 2048 x 2048.
- Unity sets colors programmatically and are for template reference only. Change the colors by clicking in their respective Color fields.
- Click Generate Template. The tools will draw the key subsections of each texture section, such as ground/mid/top floors, columns, etc. The tools will also draw black lines to show subsection centers.
- Click Save to File to save the generated texture out to a PNG, which can then be used in an image editing software of your choice.
Any type of material can be used to render buildings. To take full advantage of the Maps SDK styling features, use of the MapboxStyles materials, which provide support for three colorization layers.
To specify the materials used for building visualization, go to the gameObject that contains the AbstractMap component. Next, navigate to the VECTOR settings. Under Vector Layer Visualizers, click on a visualizer. ExtrudedBuildings is selected in this example. Next, add a material for Roof Material and Wall Material. To add a new visualizer instead of using an existing one, click Add Visualizer. Roofs and facades can use the same material or separate ones.
These layers are defined by assigning transparent mask textures to the Detail_1 and Detail_2 texture slots.
Coloring these layers can be achieved in one of two ways, depending on the material type used:
- MapboxStyles - allow you to set colors for feature layers directly in the material inspector, which works for when you want all buildings to have the same base, detail_1, and detail_2 colors. Change the colors by selecting the material and using the color picker. Specify the textures by clicking Select and adding a texture of your choice. The materials can be located in the
Mapbox > Resources > MapboxStyles > Materialsdirectory.
- MapboxStylesPerRenderer - you cannot set colors for feature layers in the inspector. Instead, Unity sets them programmatically using colors defined in a scriptable palette file. This shader uses Unity’s
[PerRendererData]tag on color properties to allow for different renderers to change those properties at runtime without creating material instances and incurring additional draw calls. To use this material, you must define a ScriptablePalette in the Material Options section of the Vector Layer Visualizer. Use it if you want buildings to have their base, detail_1, and detail_2 colors randomly assigned from a palette.
Scriptable Palettes are containers that can generate and hold a palette of colors. They inherit from Unity’s scriptable object class, which means they can be saved in a Unity project and used in multiple scenes.
Scriptable Palettes require the use of
Assign/Change the scriptable palette in use
Select the gameObject containing the AbstractMap component, and navigate to the VECTOR settings. Navigate to
Vector Layer Visualizers > ExtrudedBuildings > Material Options > Atlas Info.
Create a new Scriptable Palette
Right click or go to the Assets menu and navigate to
Create > Mapbox > ScriptablePalette to create an ScriptablePalette file.
Generate a palette of colors
- Define a Key Color. This will be used as a ‘seed’, from which other colors will be procedurally derived.
- Set a Palette Size. Choose how many colors will be in the palette.
- Define Hue, Saturation and Value ranges.
- Hue Range. Hue Range is used to define how far colors in the palette can deviate from the key color's hue.
- Saturation Range. Saturation Range is used to define how far colors in the palette can deviate from the key color's saturation.
- Value Range. Value Range is used to define how far colors in the palette can deviate from the key color's value.
- Click Generate Palette.
- To make any changes to your palette, repeat steps 1-4 until you are satisfied with it.
- You can edit the final colors in the inspector.
- If desired, set Color Overrides. This provides a method for directly setting colors for feature layers. For instance, you can enable Override Detail 2 to directly assign a chosen color to all windows. In this case, Override Detail 2 sets all windows to black to give buildings a night aesthetic.