Nvidia Corporation

Pascal Gautron

Carsten Alexander Waechter

Cyril Delalandre

Systems and methods implement a technique for altering the shape of the cells by shifting coordinates of points along cell boundaries using a set of periodic functions. To avoid having cell boundaries along the scene surfaces, wavelengths of those periodic functions are selected so they are not a multiple of an original discretization. The coordinates may be shifted along different axes of the cells and may generate different cells having a variety of different outlines to reduce a likelihood of a cell boundary being positioned along a scene boundary.

Hash cell boundary shifting for light transport simulation systems and applications

Approaches presented herein reduce the presence of temporary artifacts such, as flickering, when using spatial hashing with simulation. Flickering can be avoided, at least in part, by ensuring that the same simulation points are utilized in separate executions of an algorithm, even where the execution order can vary. This can involve selecting a single representative point for each hash cell of a spatial hash map, where simulation for that hash cell will be performed for that representative point location, regardless of execution order. Both a location index and a selector value are stored for this hash map entry in a single value, where lower bits store the location index and higher bits represent the selector value. Storing the selector value in the higher-weight bits ensures an atomic maximum operation will primarily consider the selector value, and resort to the location index only in the event of equal selector values.

Consistent sampling for spatial hashing

Approaches in accordance with various embodiments can perform spatial hash map updates while ensuring the atomicity of the updates for arbitrary data structures. A hash map can be generated for a dataset where entries in the hash map may correspond to multiple independent values, such as pixels of an image to be rendered. Update requests for independent values may be received on multiple concurrent threads, but change requests for independent values corresponding to a hash map entry can be aggregated from a buffer and processed iteratively in a single thread for a given hash map entry. In the case of multi-resolution spatial hashing where data can be stored at various discretization levels, this operation can be repeated to propagate changes from one level to another.

Concurrent dataset updates using hash maps

Various embodiments include techniques for lock-free, unordered in-place compaction of an array. The techniques include receiving a first array that includes a first plurality of data entries, generating a second array that includes a second plurality of data entries, and storing, in the second array, respective index positions of valid data entries included in the first array and invalid data entries included in the first array. The techniques further include determining invalid data entries included in a first portion of the first array based at least on the index positions, determining valid data entries included in a second portion of the first array based at least on the index positions, and replacing contents of the invalid data entries included in the first portion of the first array with contents of the valid data entries included in the second portion of the first array.

Lock-free unordered in-place compaction

Systems and methods to implement a technique for determining an environment importance sampling function. An environment map may be provided where lighting information about the environment is known, but where certain pixels within a scene associated with the environment map are shaded. From these shaded pixels, rays may be drawn in random directions to determine whether the rays are occluded or can interact with the environment map, which provides an indication of a source of lighting that can be used for light transport simulations. A mask may be generated based on these occlusions and used to update the environment importance sampling function.

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Speracedes, France

Pascal Gautron