Haptic Feedback

The SDK supports two types of haptics: buffered and non-buffered. Buffered haptics are designed to change rapidly (every 3.125ms) and work well for subtle effects. Non-buffered haptics are designed for simple effects that don't change often (every 33ms).

Buffer-Based Haptics

Running at 320Hz, each sample is 3.125 milliseconds. Because these samples are added to a buffer that holds 256 samples, the buffer can hold up to 800 milliseconds of samples.

To check the status of the buffer, call ovr_GetControllerVibrationState:

ovr_GetControllerVibrationState(ovrSession session, ovrControllerType controllerType, ovrHapticsPlaybackState* outState);

To submit to the buffer, call ovr_SubmitControllerVibration:

ovr_SubmitControllerVibration(ovrSession session, ovrControllerType controllerType, const ovrHapticsBuffer* buffer);

The following code sample shows basic haptic submission as part of a game loop:

    uint8_t amplitude = (uint8_t)round(handTrigger[t] * 255);

    result = ovr_GetControllerVibrationState(Session, touchController[t], &state);
    if (result != ovrSuccess || state.SamplesQueued >= kLowLatencyBufferSizeInSamples)
    {
        DefaultChannel.LogWarningF("%s Haptics skipped. Queue size %d", kTouchStr[t], state.SamplesQueued);
        continue;
    }

    for (int32_t i = 0; i < kLowLatencyBufferSizeInSamples; ++i)
        samples.push_back(amplitude);

    if (samples.size() > 0)
    {
        ovrHapticsBuffer buffer;
        buffer.SubmitMode = ovrHapticsBufferSubmit_Enqueue;
        buffer.SamplesCount = (uint32_t)samples.size();
        buffer.Samples = samples.data();
        result = ovr_SubmitControllerVibration(Session, touchController[t], &buffer);
        if (result != ovrSuccess)
        {
            // Something bad happened
            DefaultChannel.LogErrorF("%s: Haptics submit failed %d", kTouchStr[t], result);
        }
    }

Non-Buffered Haptics

Vibration can be enabled by calling ovr_SetControllerVibration:

ovr_SetControllerVibration( Hmd, ovrControllerType_LTouch, freq, trigger);

Vibration is enabled by specifying the frequency. Specifying 0.0f will vibrate at 160Hz. Specifying 1.0f will vibrate at 320Hz.