add disco

4 files changed, 37 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index 0fc4fc1d..ad36b549 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 USERS != ls plain | xargs basename -s .png
 
-all: plain cube thoughts pets ball heart
+all: plain cube thoughts pets ball heart disco
 
 out/plain/%.png: plain/%.png | out/plain/
 	cp $< $@
@@ -20,18 +20,25 @@ out/ball/%ball.png: plain/%.png tools/spherize | out/ball/
 out/heart/%heart.png: plain/%.png ./mkheart | out/heart/
 	./mkheart $< $@
 
+out/disco/%disco.gif: plain/%.png ./mkdisco discooverlay.mkv | out/disco/
+	./mkdisco $< $@
+
 out/%/:
 	mkdir -p $@
 
+discooverlay.mkv: mkdiscooverlay
+	./mkdiscooverlay
+
 plain: $(patsubst %, out/plain/%.png, $(USERS))
 cube: $(patsubst %, out/cube/%cube.gif, $(USERS))
 pets: $(patsubst %, out/pets/%pets.gif, $(USERS))
 thoughts: $(patsubst %, out/thoughts/%thoughts.png, $(USERS))
 ball: $(patsubst %, out/ball/%ball.png, $(USERS))
 heart: $(patsubst %, out/heart/%heart.png, $(USERS))
+disco: $(patsubst %, out/disco/%disco.gif, $(USERS))
 
 clean:
 	rm -rf out
 
-.PHONY: all plain cube thoughts pets ball heart
+.PHONY: all plain cube thoughts pets ball heart disco
 .NOTPARALLEL: cube
diff --git a/discooverlay.mkv b/discooverlay.mkv
new file mode 100644
index 00000000..5c85b883
--- /dev/null
+++ b/discooverlay.mkv
diff --git a/mkdisco b/mkdisco
new file mode 100755
index 00000000..74640000
--- /dev/null
+++ b/mkdisco
@@ -0,0 +1,2 @@
+#!/bin/sh
+ffmpeg -hide_banner -loglevel error -i "$1" -i discooverlay.mkv -filter_complex "[0]scale=150:150[in0];[1]format=yuva444p,colorchannelmixer=aa=0.2[in2];[in2][in0]scale2ref[in2][in1];[in1][in2]overlay" -y "$2"
diff --git a/mkdiscooverlay b/mkdiscooverlay
new file mode 100755
index 00000000..920536b3
--- /dev/null
+++ b/mkdiscooverlay
@@ -0,0 +1,26 @@
+#!/usr/bin/env lua
+function hue2rgb(hue)
+    local h = hue * 6
+    local x = math.floor((1.0 - math.abs(h % 2.0 - 1.0)) * 255)
+    return table.unpack(({
+        {255, x, 0},
+        {x, 255, 0},
+        {0, 255, x},
+        {0, x, 255},
+        {x, 0, 255},
+        {255, 0, x},
+    })[math.floor(h)+1])
+end
+
+local fps = 25
+local dur = 2
+local out = "discooverlay.mkv"
+local encoder = io.popen("ffmpeg -f rawvideo -pixel_format rgb24 -video_size 1x1 -framerate "..fps.." -i - -y "..out, "w")
+
+local total = fps*dur
+
+for i = 0, total-1 do
+    encoder:write(string.char(hue2rgb(i/total)))
+end
+
+encoder:close()