pokecrystal/tools/gbcpal.c

142 lines
3.5 KiB
C

#define PROGRAM_NAME "gbcpal"
#define USAGE_OPTS "[-h|--help] [-r|--reverse] out.gbcpal in.gbcpal..."
#include "common.h"
bool reverse;
void parse_args(int argc, char *argv[]) {
struct option long_options[] = {
{"reverse", no_argument, 0, 'r'},
{"help", no_argument, 0, 'h'},
{0}
};
for (int opt; (opt = getopt_long(argc, argv, "rh", long_options)) != -1;) {
switch (opt) {
case 'r':
reverse = true;
break;
case 'h':
usage_exit(0);
break;
default:
usage_exit(1);
}
}
}
struct Color {
uint8_t r, g, b;
};
const struct Color BLACK = {0, 0, 0};
const struct Color WHITE = {31, 31, 31};
uint16_t pack_color(struct Color color) {
return (color.b << 10) | (color.g << 5) | color.r;
}
struct Color unpack_color(uint16_t gbc_color) {
return (struct Color){
.r = gbc_color & 0x1f,
.g = (gbc_color >> 5) & 0x1f,
.b = (gbc_color >> 10) & 0x1f,
};
}
double luminance(struct Color color) {
return 0.299 * color.r + 0.587 * color.g + 0.114 * color.b;
}
int compare_colors(const void *color1, const void *color2) {
double lum1 = luminance(*(const struct Color *)color1);
double lum2 = luminance(*(const struct Color *)color2);
// sort lightest to darkest, or darkest to lightest if reversed
return reverse ? (lum1 > lum2) - (lum1 < lum2) : (lum1 < lum2) - (lum1 > lum2);
}
void read_gbcpal(const char *filename, struct Color **colors, size_t *num_colors) {
long filesize;
uint8_t *bytes = read_u8(filename, &filesize);
if (filesize == 0) {
error_exit("%s: empty gbcpal file\n", filename);
}
if (filesize % 2) {
error_exit("%s: invalid gbcpal file\n", filename);
}
size_t new_colors = filesize / 2;
*colors = xrealloc(*colors, (sizeof **colors) * (*num_colors + new_colors));
for (size_t i = 0; i < new_colors; i++) {
uint16_t gbc_color = (bytes[i * 2 + 1] << 8) | bytes[i * 2];
(*colors)[*num_colors + i] = unpack_color(gbc_color);
}
*num_colors += new_colors;
free(bytes);
}
void filter_colors(struct Color *colors, size_t *num_colors) {
size_t num_filtered = 0;
// filter out black, white, and duplicate colors
for (size_t i = 0; i < *num_colors; i++) {
struct Color color = colors[i];
if (color.r == BLACK.r && color.g == BLACK.g && color.b == BLACK.b) {
continue;
}
if (color.r == WHITE.r && color.g == WHITE.g && color.b == WHITE.b) {
continue;
}
if (num_filtered > 0) {
struct Color last = colors[num_filtered - 1];
if (color.r == last.r && color.g == last.g && color.b == last.b) {
continue;
}
}
colors[num_filtered++] = color;
}
*num_colors = num_filtered;
}
int main(int argc, char *argv[]) {
parse_args(argc, argv);
argc -= optind;
argv += optind;
if (argc < 2) {
usage_exit(1);
}
const char *out_filename = argv[0];
struct Color *colors = NULL;
size_t num_colors = 0;
for (int i = 1; i < argc; i++) {
read_gbcpal(argv[i], &colors, &num_colors);
}
qsort(colors, num_colors, sizeof(*colors), compare_colors);
filter_colors(colors, &num_colors);
struct Color pal_colors[4] = {
WHITE,
num_colors > 0 ? colors[0] : WHITE,
num_colors > 1 ? colors[1] : num_colors > 0 ? colors[0] : BLACK,
BLACK,
};
if (num_colors > 2) {
error_exit("%s: more than 2 colors besides black and white (%zu)\n", out_filename, num_colors);
}
uint8_t bytes[COUNTOF(pal_colors) * 2] = {0};
for (size_t i = 0; i < COUNTOF(pal_colors); i++) {
uint16_t packed_color = pack_color(pal_colors[i]);
bytes[2 * i] = packed_color & 0xff;
bytes[2 * i + 1] = packed_color >> 8;
}
write_u8(out_filename, bytes, COUNTOF(bytes));
free(colors);
return 0;
}