A System for Real-Time Deformable Terrain

Terrain constitutes an important part of many virtual environments. In computer games or simulations it is often useful to allow the user to modify the terrain since this can help to foster immersion. Unfortunately, real-time deformation schemes can be expensive and most game engines simply substitute proxy geometry or use texturing to create the illusion of deformation. We present a new terrain deformation framework which is able to produce persistent, real-time deformation by utilising the capabilities of current generation GPUs. Our method utilises texture storage, a terrain level-of-detail scheme and a tile-based terrain representation to achieve high frame rates. To accommodate a range of hardware, we provide deformation schemes for hardware with and without geometry tessellation units. Deformation using the fragment shader (no tessellation) is significantly faster than the geometry shader (tessellation) approach, although this does come at the cost of some high resolution detail. Our tests show that both deformation schemes consume a comparatively small proportion of the GPU per frame budget and can thus be integrated into more complex virtual environments