diff --git a/ws2812/ws2812.go b/ws2812/ws2812.go index 583cbbd..6e1ed35 100644 --- a/ws2812/ws2812.go +++ b/ws2812/ws2812.go @@ -18,7 +18,8 @@ var errUnknownClockSpeed = errors.New("ws2812: unknown CPU clock speed") // Device wraps a pin object for an easy driver interface. type Device struct { Pin machine.Pin - writeColorFunc func(Device, []color.RGBA) error + brightness uint8 + writeColorFunc func(Device, []color.RGBA, uint8) error } // deprecated, use NewWS2812 or NewSK6812 depending on which device you want. @@ -40,10 +41,16 @@ func NewWS2812(pin machine.Pin) Device { func NewSK6812(pin machine.Pin) Device { return Device{ Pin: pin, + brightness: 255, writeColorFunc: writeColorsRGBA, } } +// SetBrightness sets the global brightness (0-255). +func (d *Device) SetBrightness(b uint8) { + d.brightness = b +} + // Write the raw bitstring out using the WS2812 protocol. func (d Device) Write(buf []byte) (n int, err error) { for _, c := range buf { @@ -55,24 +62,35 @@ func (d Device) Write(buf []byte) (n int, err error) { // Write the given color slice out using the WS2812 protocol. // Colors are sent out in the usual GRB(A) format. func (d Device) WriteColors(buf []color.RGBA) (err error) { - return d.writeColorFunc(d, buf) + return d.writeColorFunc(d, buf, d.brightness) } -func writeColorsRGB(d Device, buf []color.RGBA) (err error) { +func writeColorsRGB(d Device, buf []color.RGBA, brightness uint8) (err error) { for _, color := range buf { - d.WriteByte(color.G) // green - d.WriteByte(color.R) // red - err = d.WriteByte(color.B) // blue + r, g, b := applyBrightness(color, brightness) + d.WriteByte(g) // green + d.WriteByte(r) // red + err = d.WriteByte(b) // blue } return } -func writeColorsRGBA(d Device, buf []color.RGBA) (err error) { +func writeColorsRGBA(d Device, buf []color.RGBA, brightness uint8) (err error) { for _, color := range buf { - d.WriteByte(color.G) // green - d.WriteByte(color.R) // red - d.WriteByte(color.B) // blue + r, g, b := applyBrightness(color, brightness) + + d.WriteByte(g) // green + d.WriteByte(r) // red + d.WriteByte(b) // blue err = d.WriteByte(color.A) // alpha } return } + +// applyBrightness scales a color by the brightness value. +func applyBrightness(c color.RGBA, brightness uint8) (r, g, b uint8) { + r = uint8((uint16(c.R) * uint16(brightness)) >> 8) + g = uint8((uint16(c.G) * uint16(brightness)) >> 8) + b = uint8((uint16(c.B) * uint16(brightness)) >> 8) + return +} diff --git a/ws2812/ws2812_rp2_pio.go b/ws2812/ws2812_rp2_pio.go index 36259e5..ffd4d0a 100644 --- a/ws2812/ws2812_rp2_pio.go +++ b/ws2812/ws2812_rp2_pio.go @@ -22,10 +22,12 @@ func newWS2812Device(pin machine.Pin) Device { return Device{Pin: pin, writeColorFunc: writeColorsRGB} } return Device{ - Pin: pin, - writeColorFunc: func(_ Device, buf []color.RGBA) error { + Pin: pin, + brightness: 255, + writeColorFunc: func(_ Device, buf []color.RGBA, brightness uint8) error { for _, c := range buf { - ws.PutRGB(c.R, c.G, c.B) + r, g, b := applyBrightness(c, brightness) + ws.PutRGB(r, g, b) } return nil },