From 9631e2e026f29f2776a744490c80ff0ae5099f90 Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@pobox.com>
Date: Sat, 25 Mar 2023 19:43:57 -0700
Subject: [PATCH] fixes

---
 dither-image.js       | 71 +++++++++++++++++++++++++++++++------------
 dither4.s             |  1 +
 video-doom/extract.sh |  2 +-
 3 files changed, 53 insertions(+), 21 deletions(-)

diff --git a/dither-image.js b/dither-image.js
index a481e21..2690485 100644
--- a/dither-image.js
+++ b/dither-image.js
@@ -585,6 +585,26 @@ function decimate(input, palette, n) {
     // preface the reserved bits
     let buckets = reserved.slice().map((c) => [atariRGB[c]]).concat([input.slice()]);
 
+    /*
+    let buckets = [input.slice()];
+    if (reserved.length > 0) {
+        let pxPerReserved = input.length;
+        for (let c of reserved) {
+            for (let i = 0; i < pxPerReserved; i++) {
+                buckets[0].unshift(atariRGB[c]);
+            }
+        }
+        console.log(buckets[0].length, 'xxx');
+    }
+    */
+
+    let magicSort = (picker) => (a, b) => {
+        let bychannel = picker(b) - picker(a);
+        if (bychannel) return bychannel;
+
+        let byluma = b.luma() - a.luma();
+        return byluma;
+    };
     let medianCut = (bucket, range) => {
         if (bucket.length < 2) {
             console.log(bucket);
@@ -594,15 +614,21 @@ function decimate(input, palette, n) {
         // Sort by the channel with the greatest range,
         // then cut the bucket in two at the median.
         if (range.g >= range.r && range.g >= range.b) {
-            bucket.sort((a, b) => b.g - a.g);
+            //bucket.sort((a, b) => b.g - a.g);
+            bucket.sort(magicSort((rgb) => rgb.g));
         } else if (range.r >= range.g && range.r >= range.b) {
-            bucket.sort((a, b) => b.r - a.r);
+            //bucket.sort((a, b) => b.r - a.r);
+            bucket.sort(magicSort((rgb) => rgb.r));
         } else if (range.b >= range.g && range.b >= range.r) {
-            bucket.sort((a, b) => b.b - a.b);
+            //bucket.sort((a, b) => b.b - a.b);
+            bucket.sort(magicSort((rgb) => rgb.b));
         }
         let half = bucket.length >> 1;
         //console.log('cutting', half, bucket.length);
-        return [bucket.slice(0, half), bucket.slice(half)];
+        let [bottom, top] = [bucket.slice(0, half), bucket.slice(half)];
+        //console.log({bottom, top});
+        return [bottom, top];
+        //return [bucket.slice(0, half), bucket.slice(half)];
     };
     while (buckets.length < n) {
         // Find the bucket with the greatest range in any channel
@@ -729,8 +755,11 @@ function decimate(input, palette, n) {
     });
     // hack
     decimated.sort((a, b) => a - b);
-    //console.log(decimated);
-    decimated[0] = 0;
+    console.log(decimated);
+
+    // we shouldn't have to do this
+    //decimated[0] = 0;
+    console.log(decimated);
 
     // Palette fits
     return dither(decimated);
@@ -837,7 +866,7 @@ async function convert(source) {
             .slice(y * width, (y + 1) * width);
         if (y > 0) {
             let error = lines[y - 1].error;
-            inputLine = inputLine.map((rgb, x) => rgb.add(error[x]));
+            inputLine = inputLine.map((rgb, x) => rgb.add(error[x]).clamp());
         }
         let line = decimate(inputLine, allColors, 4, y);
         lines.push(line);
@@ -904,12 +933,14 @@ function genAssembly(width, height, nbits, lines) {
     return `.data
 .export frame1_top
 .export frame1_bottom
+
 .export frame1_palette1_even
 .export frame1_palette1_odd
 .export frame1_palette2_even
 .export frame1_palette2_odd
 .export frame1_palette3_even
 .export frame1_palette3_odd
+
 .export displaylist
 
 .segment "BUFFERS"
@@ -918,30 +949,30 @@ function genAssembly(width, height, nbits, lines) {
 frame1_top:
 ${byte2byte(frame.bitmap.slice(0, half))}
 
-.align 128
-frame1_palette1_even:
-${byte2byte(even(frame.palette1))}
-
-.align 128
-frame1_palette2_even:
-${byte2byte(even(frame.palette2))}
-
-.align 128
-frame1_palette3_even:
-${byte2byte(even(frame.palette3))}
-
 .align 4096
 frame1_bottom:
 ${byte2byte(frame.bitmap.slice(half))}
 
+.align 128
+frame1_palette1_even:
+${byte2byte(even(frame.palette1))}
+
 .align 128
 frame1_palette1_odd:
 ${byte2byte(odd(frame.palette1))}
 
+.align 128
+frame1_palette2_even:
+${byte2byte(even(frame.palette2))}
+
 .align 128
 frame1_palette2_odd:
 ${byte2byte(odd(frame.palette2))}
 
+.align 128
+frame1_palette3_even:
+${byte2byte(even(frame.palette3))}
+
 .align 128
 frame1_palette3_odd:
 ${byte2byte(odd(frame.palette3))}
@@ -951,7 +982,7 @@ ${byte2byte(odd(frame.palette3))}
 
 .align 1024
 displaylist:
-    ; 40 lines overscan
+    ; 24 lines overscan
     .repeat 4
         .byte $70 ; 8 blank lines
     .endrep
diff --git a/dither4.s b/dither4.s
index 6513a16..64a570d 100644
--- a/dither4.s
+++ b/dither4.s
@@ -34,6 +34,7 @@ bytes_per_line = 40
 pages_per_frame = 32
 lines_per_frame = 262
 ;scanline_offset = 31 + (40 - 24) / 2
+;scanline_offset = 46
 scanline_offset = 46
 scanline_max = (lines_per_frame - scanline_offset) / 2
 
diff --git a/video-doom/extract.sh b/video-doom/extract.sh
index e3b4107..b34bcea 100644
--- a/video-doom/extract.sh
+++ b/video-doom/extract.sh
@@ -2,7 +2,7 @@ set -a
 
 mkdir -p frames
 
-TIME=37
+TIME=37.5
 
 ffmpeg \
     -i 'doom-speedrun.webm' \