Difference between revisions of "Texture types"

Revision as of 13:04, 23 August 2014

These are some of the map types used when texturing game models. In all cases, the different map types work together to produce the final image rendered onscreen. Artists create these maps in tandem to ensure the contribution from each work in balance. In most cases, these images can be considered masks for material attributes that work on a per-pixel level, instead of a single-value slider, such as transparency or gloss.

The most common types are diffuse, emissive, normal, opacity, specular, and gloss. Which types you use will be dictated by the asset itself, and the Art Direction for the project. Depending on the needs of a game, multiple types may be packed into a single file.

In a [[PBR|Physically-based rendering] scheme, the common types are albedo, microsurface, reflectivity, and normal maps.

• Brief Considerations About Materials by Pedro Toldeo is an explanation of various map types, especially specular maps.
• Texturing for Dummies by Leigh van der Byl is a PDF overview of texturing and texture types. (alternative download site)

Color Maps

• Diffuse maps are used to create the albedo, the diffuse reflection of light from a surface.
• Albedo maps are a more specialized form of diffuse used in PBR shaders, and represent only the base colors of a surface.
• Emissive map (aka Glow) mimic surfaces that emit light, like a computer monitor, a vehicle dashboard at night, or magical effects.
• Gradient map and Color look-up tables can be used to modify colors of a scene or model by mapping one color to another.
• Masking for color variation, player customizable assets, or material regions can be considered color maps.
• Detail maps are tiled detail textures that are blended in when geometry is viewed up close.

Transparency Maps

• Transparency maps, also known as opacity, are used to cut out parts of a surface, usually for alpha blending. For example: fire, grass, hair, smoke, water, windows, etc.

Bump Maps

• Bump maps are 2d grayscale maps that modify shading of geometry, typically used for fine detail of a surface.
• Normal maps are 3D bump maps that modify Vertex normals to give the appearance of higher detailed geometry.
• Radiosity normal maps are a specialized blending of light maps and normal maps.
• Displacement maps are similar to bump but store height information and modify geometry when rendered, modifying both appearance of shading and silhouette.
• Height maps are typically used to deform terrain meshes moving vertices up and down.
• Vector displacement maps are an extension of height, but can transform vertices in any axis.
• Parallax maps "slide" other textures along a surface simulating height and depth in geometry.
• DuDv maps modify UVs of a mesh to distort the other textures on a per-pixel basis.
• Flow maps are similar to DuDv, defining direction-based distortion, such as water flow or anisotropic highlighting.
• Curvature maps are notable for use during production, storing convexity/concavity in greyscale.

Specular Maps

• Specular maps control how reflective the surface is, and can adjust the shape of the reflection. Specular usually simulates only the reflections of the brightest light sources in a scene. Specular maps can also be used to control how much environment maps will appear on a surface.
• Gloss maps control how wide or narrow the specular highlight appears.

Environment Maps

Environment maps are typically used for reflective surfaces, showing the scene around the model, what is being reflected. This is a cheap hack to avoid rendering an accurate view of the actual scene, which is typically too slow to render in real time.

For more information, see Environment map.

Light Maps

Light maps are often used to store complex pre-computed lighting for a surface.