Reverse Projection: Real-Time Local Space Texture Mapping

TL;DR

Real-time decal painting on 3D models is computationally expensive with traditional approaches such as ray tracing, UV unwrapping, or forward projection. Reverse Projection uses a per-pixel, local-space projection pipeline that rasterizes the mesh into a local texture and paints directly into the target texture. The framework formalizes Local Space Texture Generation and Local Space Projection and demonstrates a device-agnostic pipeline with complexity bounded by $O(2 \cdot width \cdot height)$. On a Dell Precision 5570 with a single-threaded CPU, per-stage times are around $0.0033\pm0.003$ s, with noted limitations including unique per-triangle texture mapping and size matching, and future work proposes broad-phase culling for complex non-parametric models. This approach improves speed and versatility of in-game texture painting across diverse devices.

Abstract

We present Reverse Projection, a novel projective texture mapping technique for painting a decal directly to the texture of a 3D object. Designed to be used in games, this technique works in real-time. By using projection techniques that are computed in local space textures and outward-looking, users using low-end android devices to high-end gaming desktops are able to enjoy the personalization of their assets. We believe our proposed pipeline is a step in improving the speed and versatility of model painting.

Figures (1)

• Figure 1: Reverse Projection Framework