Added a LightRGB method to support RGB colors.

cmd/hellomk2rgb/main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"log"
+	"time"
+
+	"github.com/IanLewis/launchpad/mk2"
+	// "github.com/rakyll/launchpad/mk2"
+)
+
+func main() {
+	pad, err := mk2.Open()
+	if err != nil {
+		log.Fatalf("error while openning connection to launchpad: %v", err)
+	}
+	defer pad.Close()
+
+	// render cycles through the pure red, green, and blue palettes.
+	var palette int
+	render := func(i, j int) {
+		pad.Clear()
+		// Turn on all the buttons in sequence.
+		for i := 0; i < 8; i++ {
+			for j := 0; j < 8; j++ {
+				c := mk2.Color{}
+				switch palette {
+				case 0:
+					c.R = j + (i * 8)
+				case 1:
+					c.G = j + (i * 8)
+				case 2:
+					c.B = j + (i * 8)
+				}
+				pad.LightRGB(i, j, c)
+				time.Sleep(20 * time.Millisecond)
+			}
+		}
+		palette = (palette + 1) % 3
+	}
+
+	render(0, 0)
+	ch := pad.Listen()
+	for {
+		hit := <-ch
+		log.Printf("Button pressed at <x=%d, y=%d>", hit.X, hit.Y)
+		// Re-render the color palette again.
+		render(hit.X, hit.Y)
+	}
+
+}

mk2/launchpad.go

@@ -29,6 +29,13 @@ type Launchpad struct {
 	outputStream *portmidi.Stream
 }
 
+// Color represents an RGB color. Color values should be [0, 64) for the Launchpad Mk2
+type Color struct {
+	R int
+	G int
+	B int
+}
+
 // Hit represents physical touches to Launchpad buttons.
 type Hit struct {
 	X int
@@ -100,19 +107,31 @@ func (l *Launchpad) Read() (hits []Hit, err error) {
 	return
 }
 
-// Light lights the button at x,y with the given red, green, and blue values.
+// Light lights the button at x,y with the given palette color.
 // x and y are [0, 7]. Color is [0, 128).
-// All available colors are documented and visualized at Launchpad's Programmers Guide
+// All available colors are documented and visualized in the Launchpad's Programmers Guide
 // at https://global.novationmusic.com/sites/default/files/novation/downloads/10529/launchpad-mk2-programmers-reference-guide_0.pdf.
 func (l *Launchpad) Light(x, y, color int) error {
 	// TODO(jbd): Support top row.
 	led := int64((8-y)*10 + x + 1)
 	return l.outputStream.WriteShort(0x90, led, int64(color))
 }
 
-// Reset turns off all buttons.
-func (l *Launchpad) Reset() error {
-	// Sends a "light all ligts" SysEx command with 0 color.
+// LightRGB lights the button at x,y with the given rgb color.
+// x and y are [0, 7]. RGB color values are [0, 64).
+// This method is documented in the Launchpad's Programmers Guide under the "RGB Mode" heading.
+// at https://global.novationmusic.com/sites/default/files/novation/downloads/10529/launchpad-mk2-programmers-reference-guide_0.pdf.
+func (l *Launchpad) LightRGB(x, y int, c Color) error {
+	// This method uses RGB Mode on the Launchpad Mk2.
+	// RGB colors are set using SysEx extended mode messages.
+	led := byte((8-y)*10 + x + 1)
+	return l.outputStream.WriteSysExBytes(portmidi.Time(), []byte{0xf0, 0x00, 0x20, 0x29, 0x02, 0x18, 0x0b, led, byte(c.R), byte(c.G), byte(c.B), 0xf7})
+}
+
+// Clear turns off all the LEDs on the Launchpad.
+func (l *Launchpad) Clear() error {
+	// Sends a "light all lights" SysEx command with 0 color.
+	// This is documented in the Launchpad's Programmers Guide under the "Light all LEDs using SysEx" heading.
 	return l.outputStream.WriteSysExBytes(portmidi.Time(), []byte{0xf0, 0x00, 0x20, 0x29, 0x02, 0x18, 0x0e, 0x00, 0xf7})
 }