Distributed Texture-based Terrain Synthesis

Terrain synthesis is an important field of Computer Graphics that deals with the generation of 3D landscape models for use in virtual environments. The field has evolved to a stage where large and even infinite landscapes can be generated in realtime. However, user control of the generation process is still minimal, as well as the creation of virtual landscapes that mimic real terrain. This thesis investigates the use of texture synthesis techniques on real landscapes to improve realism and the use of sketch-based interfaces to enable intuitive user control. We present a patch-based terrain synthesis framework constrained by user-specified curvilinear features such as ridges and valleys. The framework copies patches of a Digital Elevation model from a real landscape onto the output terrain such that the output contains the curvilinear features specified by the user and exhibit the characteristics of the real landscape. A user specifies where terrain features appear in the generated terrain by providing a 2D sketch map or drawing 212D sketched curves in the sketching interface. Features are automatically extracted from the user constraints and a real landscape, and a patch-based texture synthesis guided by these features produces a realistic terrain that fits the user constraints. A novel patch merging technique is proposed to remove boundary artifacts created by overlapping patches. We show that terrains generated by our system are more realistic than current state-of-the-art terrain synthesis methods. We also present two GPU acceleration techniques and show that these parallel implementations accelerate the matching process by 6 to 30 times. We conclude that texture-based terrain synthesis provides an excellent solution to user control and realism challenges of virtual landscape generation.