An Efficient Denoising Algorithm for Global Illumination

We propose a hybrid ray-tracing/rasterization strategy for real-time rendering enabled by a fast new denoising method. We factor global illumination into direct light at rasterized primary surfaces and two indirect lighting terms, each estimated with one path-traced sample per pixel. Our factorization enables efficient (biased) reconstruction by denoising light without blurring materials. We demonstrate denoising in under 10 ms per 1280×720 frame, compare results against the leading offline denoising methods, and include a supplement with source code, video, and data.

Aggregate G-Buffer Anti-Aliasing in Unreal Engine 4

In recent years, variants of Temporal Anti-Aliasing (TAA) have become the techniques of choice for fast post-process anti-aliasing, approximating super-sampled AA amortized over multiple frames. While TAA generally greatly improves quality over previous post-process AA algorithms, the approach can also suffer from inherent artifacts, namely ghosting and flickering, in the presence of complex sub-pixel geometry and/or sub-pixel specular highlights. In this talk, we will share our experience from implementing Aggregate G-Buffer Anti-Aliasing (AGAA) in Unreal Engine 4.

The SGGX microflake distribution

We introduce the Symmetric GGX (SGGX) distribution to represent spatially-varying properties of anisotropic microflake participating media. Our key theoretical insight is to represent a microflake distribution by the projected area of the microflakes. We use the projected area to parameterize the shape of an ellipsoid, from which we recover a distribution of normals.

Design-Induced Latency Variation in Modern DRAM Chips: Characterization, Analysis, and Latency Reduction Mechanisms

Variation has been shown to exist across the cells within a modern DRAM chip. Prior work has studied and exploited several forms of variation, such as manufacturing-process- or temperature-induced variation. We empirically demonstrate a new form of variation that exists within a real DRAM chip, induced by the design and placement of different components in the DRAM chip: different regions in DRAM, based on their relative distances from the peripheral structures, require different minimum access latencies for reliable operation.

Exploiting Budan-Fourier and Vincent’s Theorems for Ray Tracing 3D Bézier Curves

We present a new approach to finding ray–cubic Bézier curve intersections by leveraging recent achievements in polynomial studies. Compared with the state-of-the-art adaptive linearization, it increases performance by 5–50 times, while also improving the accuracy by 1000X. Our algorithm quickly eliminates parts of the curve for which the distance to the given ray is guaranteed to be bigger than a model-specific threshold (maximum curve’s half-width).

Audio-Driven Facial Animation by Joint End-to-End Learning of Pose and Emotion

We present a machine learning technique for driving 3D facial animation by audio input in real time and with low latency. Our deep neural network learns a mapping from input waveforms to the 3D vertex coordinates of a face model, and simultaneously discovers a compact, latent code that disambiguates the variations in facial expression that cannot be explained by the audio alone. During inference, the latent code can be used as an intuitive control for the emotional state of the face puppet.

Spatiotemporal Variance-Guided Filtering: Real-Time Reconstruction for Path-Traced Global Illumination

We introduce a reconstruction algorithm that generates a temporally stable sequence of images from one path-per-pixel global illumination. To handle such noisy input, we use temporal accumulation to increase the effective sample count and spatiotemporal luminance variance estimates to drive a hierarchical, image-space wavelet filter. This hierarchy allows us to distinguish between noise and detail at multiple scales using local luminance variance. Physically based light transport is a long-standing goal for real-time computer graphics.

Generating stratified random lines in a square

When generating a set of uniformly distributed lines through a square, some care is needed to avoid bias in line orientation and position. We present a compact algorithm to generate unbiased uniformly distributed lines from a uniform point set over the unit square.

Exploring and Expanding the Continuum of OIT Algorithms

Order independent transparency (OIT) proves challenging for modern rasterization-based renderers. Rendering without transparency can limit the quality of visual effects, so researchers have proposed various algorithms enabling and approximating OIT. Unfortunately, this work generally has restrictions limiting its applicability. To identify directions for improvement, we performed an in-depth categorization of existing transparency techniques and placed them on a multi-dimensional continuum.

Relaxations for High-Performance Message Passing on Massively Parallel SIMT Processors

Accelerators, such as GPUs, have proven to be highly successful in reducing execution time and power con- sumption of compute-intensive applications. Even though they are already used pervasively, they are typically supervised by general-purpose CPUs, which results in frequent control flow switches and data transfers as CPUs are handling all communication tasks. However, we observe that accelerators are recently being augmented with peer-to-peer communication capabilities that allow for autonomous traffic sourcing and sinking.

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