characters

resources/gfx/characters/costumes/make_character_color_variants.sh

@@ -0,0 +1,140 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+variants=(black blue green grey red white)
+references=(character_001_isaac character_002_magdalene)
+
+usage() {
+    printf 'Usage: %s INPUT.png\n' "$(basename "$0")" >&2
+}
+
+if [[ $# -ne 1 || "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
+    usage
+    exit 1
+fi
+
+if command -v magick >/dev/null 2>&1; then
+    im=(magick)
+elif command -v convert >/dev/null 2>&1; then
+    im=(convert)
+else
+    printf 'error: ImageMagick is required; expected magick or convert in PATH\n' >&2
+    exit 1
+fi
+
+script_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+input="$1"
+
+if [[ ! -f "$input" ]]; then
+    printf 'error: input file not found: %s\n' "$input" >&2
+    exit 1
+fi
+
+case "$(basename -- "$input")" in
+    *.png|*.PNG) ;;
+    *)
+        printf 'error: input must be a PNG file: %s\n' "$input" >&2
+        exit 1
+        ;;
+esac
+
+for reference in "${references[@]}"; do
+    reference_base="$script_dir/${reference}.png"
+    if [[ ! -f "$reference_base" ]]; then
+        printf 'error: missing reference file: %s\n' "$reference_base" >&2
+        exit 1
+    fi
+done
+
+input_dir="$(cd -- "$(dirname -- "$input")" && pwd)"
+input_name="$(basename -- "$input")"
+stem="${input_name%.*}"
+
+case "$stem" in
+    *_black|*_blue|*_green|*_grey|*_red|*_white)
+        stem="${stem%_*}"
+        ;;
+esac
+
+build_palette_map() {
+    local variant="$1"
+    local reference
+    local reference_base
+    local reference_variant
+
+    for reference in "${references[@]}"; do
+        reference_base="$script_dir/${reference}.png"
+        reference_variant="$script_dir/${reference}_${variant}.png"
+
+        if [[ ! -f "$reference_variant" ]]; then
+            printf 'error: missing reference file: %s\n' "$reference_variant" >&2
+            return 1
+        fi
+
+        paste \
+            <("${im[@]}" "$reference_base" -depth 8 txt:-) \
+            <("${im[@]}" "$reference_variant" -depth 8 txt:-) |
+            awk -F '\t' -v reference="$reference" '
+                function pixel_hex(line, parts, count, i) {
+                    count = split(line, parts, /[[:space:]]+/)
+                    for (i = 1; i <= count; i++) {
+                        if (parts[i] ~ /^#[[:xdigit:]]{6}([[:xdigit:]]{2})?$/) {
+                            return toupper(parts[i])
+                        }
+                    }
+                    return ""
+                }
+
+                NR == 1 { next }
+
+                {
+                    source = pixel_hex($1)
+                    target = pixel_hex($2)
+                    if (source == "" || target == "" || source == target) {
+                        next
+                    }
+                    print source, target, reference
+                }
+            '
+    done |
+        awk '
+            {
+                source = $1
+                target = $2
+                reference = $3
+                if ((source in targets) && targets[source] != target) {
+                    printf "error: conflicting map for %s: %s from %s and %s from %s\n", source, targets[source], sources[source], target, reference > "/dev/stderr"
+                    exit 2
+                }
+                targets[source] = target
+                sources[source] = reference
+            }
+
+            END {
+                for (source in targets) {
+                    print source, targets[source]
+                }
+            }
+        ' |
+        sort
+}
+
+for variant in "${variants[@]}"; do
+    output="$input_dir/${stem}_${variant}.png"
+    args=("$input" -alpha on)
+    pair_count=0
+
+    while read -r source target; do
+        [[ -n "$source" && -n "$target" ]] || continue
+        args+=(-fill "$target" -opaque "$source")
+        pair_count=$((pair_count + 1))
+    done < <(build_palette_map "$variant")
+
+    if [[ "$pair_count" -eq 0 ]]; then
+        printf 'error: no palette replacements found for %s\n' "$variant" >&2
+        exit 1
+    fi
+
+    "${im[@]}" "${args[@]}" "$output"
+    printf 'exported %s\n' "$output"
+done