Percentage-Closer Filtering

Computer Graphics · Shadows · 1987 · also: PCF · percentage-closer-filtering.yaml

Takes several depth comparisons across the shadow map footprint and averages the binary results. Filtering the comparisons rather than the depths is the key: averaging depths is meaningless.

• supersedescorrects · extends
• classifiesspecializes · part-of
• substitutes forapproximates · alternative-to
• depends onrequires · validates

Colour is the family; a dashed line is the second member of it.

This node

• correctsfixes a defect in Shadow Mappinga single depth compare gives hard, aliased edges

Referenced by

• extendsPercentage-Closer Soft Shadows adds capability to thiskernel width from blocker distance gives contact hardening
• correctsVariance Shadow Maps fixes a defect in thisPCF cost grows with filter width; this prefilters

References

• Rendering Antialiased Shadows with Depth Maps — Reeves, Salesin, Cook — 1987 · link
• Background — Shadow mapping on Wikipedia