Terrain Generation with Heightmaps

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Terrain Generation with Heightmaps

• CS 536
• By Mauricio Castellanos

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Terrains should

• appear continuous to the player.
• Appear realistic to the setting of the game
• Appear static, even if a level-of-detail(LOD)
  algorithm is used.

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What will I cover

• Heightmaps
• Terrain generation

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Heightmaps

• A standard way of creating 3d terrains is through
  the use of heightmaps
• A heightmap is simply a 2d array of values

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Terrain Generation

• Steps to create a heightmap
• Initial Creation
• Midpoint Displacement
• Fault lines
• Hill Algorithm
• Smoothing
• Scaling
• Adjusting

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Midpoint Displacement

• Also known as the diamond square method.
• Midpoint displacement is a subdivision algorithm
  that starts out adding larger details to the
  terrain and creates smaller more intricate detail
  as it subdivides the heightmap.
• There are 2 steps
• The diamond step
• The square step.

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Midpoint displacement example
Figure 2
Figure 3
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Fault lines method
Figure 3
Figure 1
Figure 2
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Hill Algorithm

• The hill algorithm is a simple iterated algorithm
  with a few parameters that can be varied to
  change the characteristics of the terrain
• 1. Start with a flat terrain (initialize all
  height values to zero).
• 2. Pick a random point on or near the terrain,
  and a random radius between some predetermined
  minimum and maximum. Carefully choosing this min
  and max will make a terrain rough and rocky or
  smooth and rolling.
• 3. Raise a hill on the terrain centered at the
  point, having the given radius.
• 4. Go back to step 2, and repeat as many times
  as necessary. The number of iterations chosen
  will affect the appearance of the terrain.
• 5. Normalize the terrain.
• 6. Flatten out the valleys

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One hill
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Multiple Hills
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Terrain Generation

• Steps to creating a heightmap
• Initial Creation
• Midpoint Displacement
• Fault lines
• Hill Algorithm
• Smoothing
• Scaling
• Adjusting

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DEMO
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Sources

• http//collective.valve-erc.com/index.php?doc1040
  644009-23694100
• http//www.gameprogrammer.com/fractal.htmldiamond
  
• http//www.robot-frog.com/3d/hills/hill.html
• Terrain rendering brute force http//www.two-king
  s.de/tutorials/terrain/terrain01.html
• http//tulrich.com/geekstuff/chunklod.html
• http//tulrich.com/geekstuff/siggraph02-slides/img
  0.html