Mix-Max: A Content-Aware Operator for Real-Time Texture Transitions

Mixing textures is a basic and ubiquitous operation in data-driven algorithms for real-time texture generation and rendering. It is usually performed either by linear blending, or by cutting. We propose a new mixing operator which encompasses and extends both, creating more complex transitions that adapt to the texture's contents. Our mixing operator takes as input two or more textures along with two or more priority maps, which encode how the texture patterns should interact. The resulting mixed texture is defined pixel-wise by selecting the maximum of both priorities. We show that it integrates smoothly into two widespread applications: transition between two different textures, and texture synthesis that mixes pieces of the same texture. We provide constant-time and parallel evaluation of the resulting mix over square footprints of MIP-maps, making our operator suitable for real-time rendering. We also develop a micro-priority model, inspired by micro-geometry models in rendering, which represents sub-pixel priorities by a statistical distribution, and which allows for tuning between sharp cuts and smooth blend.