Material

Besides the geometry a landscape also needs materials. It provides the texture to put on the terrain and how to blend them with each other.

Virtual Textures

These are techniques based around the concept of virtual textures, it's like a big, really big texture.

• • Virtual Texture Terrain - 2013

Adaptive Virtual Textures - 2014

Instead of a virtual texture over the whole terrain chunks of the terrain is assigned virtual texture space at run-time. How much each chunk gets depends on the importance of the chunk so a chunk close by gets more details. Chunks can get it's virtual texture size downgraded or upgraded at run-time.

• • Adaptive Virtual Texture Rendering in Far Cry 4 - 2015

Procedural Virtual Textures / Shader Splatting - 2009

Use a virtual texture over the terrain but fill it in at run-time.

• • Terrain in Battlefield 3: A Modern, Complete and Scalable System - 2012

  • Terrain Rendering in Frostbite using Procedural Shader Splatting - 2009

Mega Texture - 2007

This is the first logical step when one has a really big texture. Stretch it over the whole world and make people paint it however they wish. Used in IdTech4 (Enemy Territory: Quake Wars), IdTech5 (Rage, Wolfenstein: The New Order) and IdTech6 (Doom). The downside of mega textures is a really big set of data to store/load and lots of texture space for artists to paint.

• • Software Virtual Textures - 2012. Notes / Other Publications

  • MegaTexture in Quake Wars - 2007

Blending

Texture Splatting - 2000

Each texture that is used on the terrain also have a alpha mask texture. The mask is stretched over the whole terrain and it selects how much of each texture should be blended in at that location of the height map.

• • Advanced Terrain Texture Splatting - 2013

  • 3D Landscape Rendering With Texture Splatting - 2007

  • Texture Splatting in Direct3D - 2005

  • Terrain Texture Compositing by Blending in the Frame-Buffer - 2000

• Unreal 3 Terrain Advanced Textures

Vertex Splatting - 2000

Each vertex has a vertex color or other per vertex data that tell how much of each texture should be used at that vertex. So if the vertex color is used then four textures can be blended onto the terrain. This is like a lower detail version of texture splatting but it makes it possible to avoid a texture switch on each height map if many of them are used.

• • Vertex Colors as Splat Map for Terrain Texture - 2014

Terrain coloring -

A single gray scale noise texture is tiled all over the terrain to provide the details. A single color texture is stretched over the whole terrain and it is mixed with the noise texture to provide the final result.

• • Texturing Heightmaps - 2005

Other

Tile - 1994

Each quad (tile) in the heightmap is given it's own texture. A 32x32 heightmap needs a 31x31 tag map that tell what texture each tile should use. The tag need to contain the index of the texture to use and can also include how it will be rotated or flipped when placed on the tile. Transitions between areas such as grass to sand is done by making transition textures for each possible combination.

• • Tiled Terrain - 2001

Solid - Around the time of the Fall of the Western Roman Empire

Set the background color to light blue for the sky and green for the ground.

Reference

Triplanar Mapping - 2014

Use Tri-Planar Texture Mapping for Better Terrain - 2014

Advanced Terrain Texture Splatting - 2013

Terrain - Triplanar UV mapping - 2010

Terrain - Multi-texturing - 2010

Triplanar Texturing

Efficient Normal Computations for Terrain Lighting in DirectX 10 - 2013

Advanced Terrain Texture Splatting - 2013