三叔的数字花园

XR Composition Layer architecture separates different content types into independent layers (Projection, Quad, Cylinder, etc.) that are merged by the Compositor before display. This design primarily addresses image quality degradation from dual non-point-to-point sampling in traditional XR rendering pipelines by allowing UI and flat content to be submitted directly as composition layers, eliminating one sampling stage. Real-world examples show YVR2's Home interface composed of a background Projection layer and two UI Quad layers. Composition layers also enable multi-application content integration, such as coordinated display of passthrough video, curved UI, and system dialogs in MR scenarios.

Resolution describes the pixel count of an image, reflecting the sampling frequency of continuous signals. Higher resolution means higher sampling frequency, enabling better reconstruction of high-frequency details. However, higher resolution isn't always better - it must match signal frequency requirements. The sampling theorem states that sampling frequency must be at least twice the maximum signal frequency for accurate reconstruction. Fourier transforms reveal that signals decompose into sine waves of different frequencies, with high frequencies corresponding to fine details like object edges. Insufficient resolution causes aliasing in high-frequency signals like sharp black-white transitions. Optimizing display quality requires balancing resolution with signal frequency to avoid resource waste from oversampling.

In XR, objects typically need to be rendered in stereo, meaning content must be drawn to both left and right eye textures. This rendering approach is called Stereo Rendering. This article covers various stereo rendering techniques, including the common Multi-Pass and Multi-View methods, as well as Quad-View specifically designed for eye-tracking devices. It primarily explains the differences in texture count and DrawCall count among these rendering approaches.