void UpdateFrequency(float f) { int newFreqKnobIndex = (int)(f / frequencyStep); if (newFreqKnobIndex != lastFreqKnobIndex && newFreqKnobIndex >= 0 && newFreqKnobIndex < knobPositions) { string fileName = String.Format("frequencyknob{0:00}.png", newFreqKnobIndex); var spriteFrame = CCSpriteFrameCache.SharedSpriteFrameCache[fileName]; frequencyKnob.ReplaceTexture(spriteFrame.Texture, spriteFrame.TextureRectInPixels); lastFreqKnobIndex = newFreqKnobIndex; if (isSwitchedOn) { CocosJuce.Api.StartTestTone(f, 0.8f); } frequencyLabel.Text = minFrequency + (newFreqKnobIndex * frequencyStep) + " Hz"; } }