From ece161d6d6d972514bd8fc187e4c7e79d036c152 Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@pobox.com>
Date: Sun, 4 Dec 2022 14:21:46 -0800
Subject: [PATCH] WIP 4-frame output

---
 Makefile        |  4 +++-
 dither-image.js | 33 ++++++++++++++++++++++++---------
 pack-wav.js     |  2 ++
 3 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/Makefile b/Makefile
index 69ad089..576d4f3 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ all : sample0.xex sample1.xex sample2.xex sample3.xex sample4.xex sample5.xex sa
 #           $@ is output
 
 %.s : %.jpg dither-image.js
-	node dither-image.js $< $@ $@.png
+	node dither-image.js $< $@
 
 chickens.s : chickens.wav pack-wav.js
 	node pack-wav.js $< $@
@@ -24,6 +24,8 @@ clean :
 	rm -f sample[0-6].o
 	rm -f sample[0-6].xex
 	rm -f sample[0-6].s.png
+	rm -f sample[0-6].s.0.png
+	rm -f sample[0-6].s.1.png
 	rm -f chickens.s
 	rm -f chickens.o
 
diff --git a/dither-image.js b/dither-image.js
index e502cfe..717f1ef 100644
--- a/dither-image.js
+++ b/dither-image.js
@@ -383,8 +383,8 @@ let atariRGB = [
  * @param {RGB[]} input source scanline data, in linear RGB
  * @param {number[]} palette - current working palette, as Atari 8-bit color values (low nybble luminance, high nybble hue)
  * @param {number} n - target color count
- * @param {Object} inputError
- * @returns {{output: Uint8Array, palette: number[], error: {red: Float64Array, green: Float64Array, blue: Float64Array}}}
+ * @param {RGB[]} inputError
+ * @returns {{output: Uint8Array, palette: number[], error: RGB[]}}
  */
 function decimate(input, palette, n, inputError) {
     // to brute-force, the possible palettes are:
@@ -446,9 +446,10 @@ function decimate(input, palette, n, inputError) {
             popularity[pick]++;
 
             if (x == width - 1) {
-                let half = nextError.divide(2);
+                let half = nextError.divide(4);
                 error.next[x - 1].inc(half);
                 error.next[x].inc(half);
+                // drop half the error on the floor at the edge ;_;
             } else {
                 let quarter = nextError.divide(4);
                 error.right = quarter;
@@ -565,7 +566,7 @@ function imageToLinearRGB(rgba) {
  * @param {string} source path to source image file
  * @returns {{width: number, height: number, lines: {palette: Array, output: Uint8Array}[]}}
  */
-async function convert(source, nbits) {
+async function convert(source, nbits, reps) {
 
     let {
         width,
@@ -590,6 +591,15 @@ async function convert(source, nbits) {
         throw new Error('inconsistent data size');
     }
 
+    if (reps > 1) {
+        height *= reps;
+        let rgba2 = new Uint8Array(rgba.length * reps);
+        for (let i = 0; i < reps; i++) {
+            rgba2.set(rgba, rgba.length * i);
+        }
+        rgba = rgba2;
+    }
+
     let input = imageToLinearRGB(rgba);
 
     if (input.length != width * height) {
@@ -649,7 +659,7 @@ function genAssembly(width, height, nbits, lines) {
     let palette2 = new Uint8Array(height);
     let palette3 = new Uint8Array(height);
     let bitmap = new Uint8Array(stride * height);
-    for (let y = 0; y < height; y++) {
+    for (let y = 0; y < lines.length; y++) {
         palette1[y] = lines[y].palette[1];
         palette2[y] = lines[y].palette[2];
         palette3[y] = lines[y].palette[3];
@@ -723,19 +733,24 @@ async function saveImage(width, height, lines, dest) {
 }
 
 async function main() {
-    if (process.argv.length < 5) {
-        console.error("Usage: node dither-image.js source-image.jpg dest-asm.s dest-preview.png");
+    if (process.argv.length < 3) {
+        console.error("Usage: node dither-image.js source-image.jpg dest-asm.s");
         process.exit(1);
     }
 
     let nbits = 2;
+    let reps = 4;
 
-    let {width, height, lines} = await convert(process.argv[2], nbits);
+    let {width, height, lines} = await convert(process.argv[2], nbits, reps);
 
     let asm = genAssembly(width, height, nbits, lines);
     writeFileSync(process.argv[3], asm, "utf-8");
 
-    await saveImage(width, height, lines, process.argv[4]);
+    let heightPerFrame = height / reps;
+    for (let i = 0; i < reps; i++) {
+        let slice = lines.slice(i * heightPerFrame, (i + 1) * heightPerFrame);
+        await saveImage(width, heightPerFrame, slice, `${process.argv[3]}.${i}.png`);
+    }
 
     process.exit(0);
 }
diff --git a/pack-wav.js b/pack-wav.js
index c60cca5..614aefe 100644
--- a/pack-wav.js
+++ b/pack-wav.js
@@ -62,6 +62,8 @@ let infile = process.argv[2];
 let outfile = process.argv[3];
 
 let buffer = readFileSync(infile);
+// @FIXME fix
+buffer = buffer.slice(0, 262);
 let asm = wav2assembly(buffer);
 writeFileSync(outfile, asm, 'utf-8');