Two New Methods for Real-Time Per-Face Texture Mapping (Ptex)

Abstract: Ptex (Per-Face Texture Mapping for Production Rendering) is a technology unveiled by Disney in 2008 that automatizes the process of applying textures to 3D models but is rarely used in real-time contexts, where this process is still largely manual and time consuming. This report aims to compare two new real-time methods, Reduced Traverse and Hybrid, to two existing ones, Discard and Traverse, which could give new insight into the feasibility of widespread real-time Ptex and consequent resource savings. Reduced Traverse renders using Traverse along texture seams and in a simpler manner elsewhere, while Hybrid is a combination of Discard and Traverse. The performance of the implementations was compared in terms of time per frame, and their render quality was compared in terms of perceived similarity to a reference. We found that one of our methods, Reduced Traverse, outperformed all other methods when MSAA (Multi-Sample Anti-Aliasing) was disabled, and had the highest perceived quality of output of all methods when MSAA was enabled, while still performing at least as well as Discard and Traverse, depending on the scenario. In addition, the Hybrid method had the second-highest perceived quality while sometimes performing similarly to Traverse and other times similarly to Discard, depending on scenario. Disabling MSAA for Reduced Traverse resulted in its quality being slightly lower than the other implementations, likely caused by increased unevenness along the outer edges of the renders. There is potential for future research on the heuristic employed by Hybrid; Further improvements to Reduced Traverse; on objective human perception modelling; on the limitations of Reduced Traverse and Hybrid; and on even faster real-time Ptex methods to act as feasible alternatives to UV-unwrapping in real-time applications.