UImportanceSamplingLibrary::RandomSobolCell2D
#include "Kismet/ImportanceSamplingLibrary.h"
Access: public
Specifiers: staticUFUNCTIONBlueprintPure
Description
Returns a Sobol-distributed 2D position within a specific cell of a stratified grid, useful for jittered/stratified sampling patterns like Poisson-disk-style scattering.
Caveats & Gotchas
- • NumCells is silently rounded up to the next power of two, so the effective grid resolution may be larger than requested — don't assume exact cell counts for indexing elsewhere.
- • Cell coordinates are expected as integer grid coordinates packed into an FVector2D, not normalized 0-1 positions.
- • For stepping through consecutive indices within the same cell, NextSobolCell2D avoids recomputation.
Signature
static FVector2D RandomSobolCell2D(int32 Index, int32 NumCells = 1, FVector2D Cell = FVector2D(0,0), FVector2D Seed = FVector2D(0,0))Parameters
| Name | Type | Description | Default |
|---|---|---|---|
| Index | int32 | Which sequential point in the cell, starting at 0. | — |
| NumCells | int32 | Size of the cell grid, 1 to 32768. Rounded up to the next power of two. | 1 |
| Cell | FVector2D | Integer grid cell coordinate to draw the point from. | FVector2D(0,0) |
| Seed | FVector2D | Random 2D seed (components in the range 0-1) to randomize across multiple sequences. | FVector2D(0,0) |
Return Type
FVector2D Example
Scatter points within a grid cell C++
const FVector2D Point = UImportanceSamplingLibrary::RandomSobolCell2D(0, 16, FVector2D(3, 5), FVector2D(0.1f, 0.7f));
// Point is a jittered 2D sample within grid cell (3,5) of a 16x16 gridTags
Version History
Introduced in: 5.0
| Version | Status | Notes |
|---|---|---|
| 5.6 | stable | — |
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