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# FFPERIODIC

A structure containing type-specific information for certain effects.

```
struct FFPERIODIC
```

## Overview

Used with the SINE, SQUARE, TRIANGLE, SAWTOOTHUP, and SAWTOOTHDOWN effects.

A pointer to a single FFPERIODIC structure for an effect is passed in the lpvTypeSpecificParams member of the FFEFFECT structure. A Force Feedback plugIn cannot provide support for all values in the **dwPhase** member. In this case, the value is rounded off to the nearest supported value.

## Topics

### Initializers

[`init()`](/documentation/ForceFeedback/FFPERIODIC/init())

[`init(dwMagnitude: DWORD, lOffset: LONG, dwPhase: DWORD, dwPeriod: DWORD)`](/documentation/ForceFeedback/FFPERIODIC/init(dwMagnitude:lOffset:dwPhase:dwPeriod:))

### Instance Properties

[`var dwMagnitude: DWORD`](/documentation/ForceFeedback/FFPERIODIC/dwMagnitude)

Magnitude of the effect, in the range from 0 through 10,000. If an envelope is applied to this effect, the value represents the magnitude of the sustain. If no envelope is applied, the value represents the amplitude of the entire effect.

[`var dwPeriod: DWORD`](/documentation/ForceFeedback/FFPERIODIC/dwPeriod)

Period of the effect, in microseconds.

[`var dwPhase: DWORD`](/documentation/ForceFeedback/FFPERIODIC/dwPhase)

Position in the cycle of the periodic effect at which playback begins, in the range from 0 through 35,999.

[`var lOffset: LONG`](/documentation/ForceFeedback/FFPERIODIC/lOffset)

Offset of the effect. The range of forces generated by the effect is **lOffset** minus **dwMagnitude** to **lOffset** plus **dwMagnitude**. The value of the **lOffset** member is also the baseline for any envelope that is applied to the effect.

## Relationships

### Conforms To

[`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable)

[`Sendable`](/documentation/Swift/Sendable)

---

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