From a9900d7b430614e86e8c5f7442187d94b7bb037f Mon Sep 17 00:00:00 2001
From: Norwin Roosen <git@nroo.de>
Date: Fri, 1 Jan 2021 06:29:14 +0100
Subject: [PATCH] new rgbsplit

---
 pixelflut/flut.go | 18 +++++++++---------
 render/image.go   | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/pixelflut/flut.go b/pixelflut/flut.go
index 1d470b3..a7c31e5 100644
--- a/pixelflut/flut.go
+++ b/pixelflut/flut.go
@@ -3,7 +3,6 @@ package pixelflut
 import (
 	"fmt"
 	"image"
-	"image/color"
 	"sync"
 	"time"
 
@@ -115,14 +114,15 @@ func Flut(t FlutTask, stop chan bool, wg *sync.WaitGroup) {
 
 func generateCommands(t FlutTask) (cmds commands) {
 	if t.RGBSplit {
-		white := color.NRGBA{0xff, 0xff, 0xff, 0xff}
-		imgmod := render.ImgColorFilter(t.Img, white, color.NRGBA{0xff, 0, 0, 0xff})
-		cmds = append(cmds, commandsFromImage(imgmod, t.RenderOrder, t.Offset.Add(image.Pt(-10, -10)))...)
-		imgmod = render.ImgColorFilter(t.Img, white, color.NRGBA{0, 0xff, 0, 0xff})
-		cmds = append(cmds, commandsFromImage(imgmod, t.RenderOrder, t.Offset.Add(image.Pt(10, 0)))...)
-		imgmod = render.ImgColorFilter(t.Img, white, color.NRGBA{0, 0, 0xff, 0xff})
-		cmds = append(cmds, commandsFromImage(imgmod, t.RenderOrder, t.Offset.Add(image.Pt(-10, 10)))...)
+		r, g, b := render.ImgRGBSplit(t.Img, 10)
+		cmds = append(cmds, commandsFromImage(r, t.RenderOrder, t.Offset)...)
+		cmds = append(cmds, commandsFromImage(g, t.RenderOrder, t.Offset)...)
+		cmds = append(cmds, commandsFromImage(b, t.RenderOrder, t.Offset)...)
+		if t.RenderOrder == Shuffle {
+			cmds.Shuffle()
+		}
+	} else {
+		cmds = append(cmds, commandsFromImage(t.Img, t.RenderOrder, t.Offset)...)
 	}
-	cmds = append(cmds, commandsFromImage(t.Img, t.RenderOrder, t.Offset)...)
 	return
 }
diff --git a/render/image.go b/render/image.go
index 1e9605a..b065c98 100644
--- a/render/image.go
+++ b/render/image.go
@@ -63,6 +63,25 @@ func ImgColorFilter(img *image.NRGBA, from, to color.NRGBA) *image.NRGBA {
 	return r
 }
 
+// ImgRGBSplit returns three images containing the RGB components, optionally shifted by some offset
+func ImgRGBSplit(img *image.NRGBA, shift int) (*image.NRGBA, *image.NRGBA, *image.NRGBA) {
+	bounds := img.Bounds().Inset(-shift)
+	r := image.NewNRGBA(bounds)
+	g := image.NewNRGBA(bounds)
+	b := image.NewNRGBA(bounds)
+	for x := bounds.Min.X; x < bounds.Max.X; x++ {
+		for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
+			c := img.At(x, y).(color.NRGBA)
+			if c.A != 0 {
+				r.Set(x-shift, y-shift, color.NRGBA{R: c.R, A: c.A / 3})
+				g.Set(x+shift, y, color.NRGBA{G: c.G, A: c.A / 3})
+				b.Set(x-shift, y+shift, color.NRGBA{B: c.B, A: c.A / 3})
+			}
+		}
+	}
+	return r, g, b
+}
+
 func ScaleImage(img image.Image, factor int) (scaled *image.NRGBA) {
 	b := img.Bounds()
 	scaledBounds := image.Rect(0, 0, b.Max.X*factor, b.Max.Y*factor)