3D Game Programming All in One

By Kenneth C. Finney

Chapter 12

Terrains

Terrains

• For outdoor game environments

• Terrain is a topography model combined with ground cover textures

Terrains

Terrains Explained– Tiles are the basic terrain unit– Terrain tiles are a collection of

polygons, like any other 3D model

Terrains

Terrains Explained– Fidelity : accuracy of terrain– Spread : uniqueness of terrain

areas, related to tile repetition– Freedom : ability of player

characters to move within the terrain

Terrains

Terrains Explained

Terrain Data can be obtained from

U.S. Geological Survey

Formats: – Digital Elevation Model (DEM)– Digital Terrain Model (DTM)– Spatial Data Transfer Standard

(SDTS)

Terrains

Terrain Modeling

• External modeling method: terrain as another object in the game world

• Internal method: game engine contains specialized terrain rendering code

Terrains

Height Maps

• Grayscale images (8 bits per pixel) that represent terrain

• Similar to topographical maps

• Resolution is an issue (leads to either small tiles, or poor fidelity)

Terrains

Terrain Cover

• Textures used to represent soil types, flora, debris, and litter– Grass, Flowers, Dirt, Pebbles– Rocks, Trash, Litter, Pavement– Concrete, Moss, Sand, Stone

Terrains

Tiling

• Issues similar to those found in structure textures– seamless transitions– appropriate lighting

Terrains

Lab 1: Terrain

• Use paint program to create height map from a contour map

• Mathematically determine required image sizes

• Use the Terraform Editor to add height map game world

Terrains

Applying Terrain Cover

• Cover textures look best when created for tiling

• Use grid textures to assist with sizing and sight lines

• Paint terrain using the built-in Torque Terrain Texture Painter

Terrains

Lab 2: Terrain Cover

• Use images to create terrain cover

• Use the Terrain Texture Painter to apply terrain cover

• Add terrain cover (materials) to available selection

• Use guide images to apply cover

Summary

• Terrain = topography + cover

• Terrain characteristics: fidelity, spread, freedom

• Source data: USGS (real world), maps, onsite measurement

• Height-maps are like topographical maps

• Adjust height-maps to match game world size