Diamond Square — Terrain Generator in C

A minimal C implementation of the Diamond-Square algorithm for procedural terrain generation. Produces heightmaps rendered as 1024x1024 images using SDL2.

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Examples

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Requirements

• GCC or any C compiler
• SDL2

On Debian/Ubuntu:

sudo apt install libsdl2-dev

On macOS with Homebrew:

brew install sdl2

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Build

gcc main.c -o out -lSDL2

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Run

./out

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Algorithm

The Diamond-Square algorithm is a method for generating realistic fractal terrain. Starting from a 2D grid with randomized corner values, it proceeds in two alternating steps:

• Diamond step — for each square in the grid, compute the midpoint and assign it the average of the four corners plus a random offset.
• Square step — for each diamond, compute the midpoint of each edge and assign it the average of the surrounding points plus a random offset.

The random offset is scaled down at each iteration, producing a natural-looking roughness that decreases at finer scales. The result is a heightmap with fractal properties similar to real terrain.

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References

• Explanation video by SimonDev
• Wikipedia — Diamond-square algorithm