87 lines
1.9 KiB
Go
87 lines
1.9 KiB
Go
package main // import "github.com/serverwentdown/leet"
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import (
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"log"
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ws2811 "github.com/rpi-ws281x/rpi-ws281x-go"
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)
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// TODO: full-sized grid with multiple channels mapped onto the grid
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type Drawer struct {
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layers [][]uint32
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length int
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device *ws2811.WS2811
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}
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func NewDrawer(length int) (*Drawer, error) {
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opt := ws2811.DefaultOptions
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opt.Channels[0].LedCount = length
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d := &Drawer{}
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d.length = length
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d.layers = make([][]uint32, 100)
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dev, err := ws2811.MakeWS2811(&opt)
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if err != nil {
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return nil, err
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}
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err = dev.Init()
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if err != nil {
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return nil, err
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}
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d.device = dev
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return d, nil
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}
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func (d *Drawer) SetLayer(layer int32, dots []uint32) {
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d.layers[layer] = dots
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}
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func (d *Drawer) SetLayerOrFill(layer int32, dots []uint32, fill uint32) {
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if dots == nil {
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fillDots := make([]uint32, d.length)
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for i := 0; i < d.length; i++ {
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fillDots[i] = fill
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}
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d.layers[layer] = fillDots
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} else {
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d.SetLayer(layer, dots)
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}
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}
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func (d *Drawer) Draw() error {
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for i := 0; i < len(d.device.Leds(0)); i++ {
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dot := mix(d.layers, i)
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d.device.Leds(0)[i] = dot
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}
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if err := d.device.Render(); err != nil {
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return err
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}
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return nil
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}
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func mix(layers [][]uint32, j int) uint32 {
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var base uint32
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for i := 0; i < len(layers); i++ {
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base = mixColors(base, layers[i][j])
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}
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return base
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}
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func mixColors(a uint32, b uint32) uint32 {
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// Extract channels
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aa, ba := uint32(a>>24), uint32(b>>24)
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ar, br := a&uint32(0x00FF0000)>>16, b&uint32(0x00FF0000)>>16
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ag, bg := a&uint32(0x0000FF00)>>8, b&uint32(0x0000FF00)>>8
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ab, bb := a&uint32(0x000000FF), b&uint32(0x000000FF)
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// Apply alpha computation to each channel
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log.Println(aa, ar, ag, ab, ba, br, bg, bb)
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oa := uint32(ba*(255-aa)/255 + aa)
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or := uint32(br*ba*(255-aa)/(255*255) + ar*aa/255)
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og := uint32(bg*ba*(255-aa)/(255*255) + ag*aa/255)
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ob := uint32(bb*ba*(255-aa)/(255*255) + ab*aa/255)
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return (oa << 24) | (or << 16) | (og << 8) | ob
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}
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