ref: fbcc8d1b0e05cace2abe2083a88a8c2304efc9d7
dir: /tools/bpp2png.c/
#define PROGRAM_NAME "bpp2png" #define USAGE_OPTS "[-h|--help] [-w width] [-d depth] [-p in.gbcpal] [-t] in.2bpp|in.1bpp out.png" #include "common.h" #include "lodepng/lodepng.h" struct Options { unsigned int width; unsigned int depth; const char *palette; bool transpose; }; typedef uint8_t Palette[4][3]; void parse_args(int argc, char *argv[], struct Options *options) { struct option long_options[] = { {"width", required_argument, 0, 'w'}, {"depth", required_argument, 0, 'd'}, {"palette", required_argument, 0, 'p'}, {"transpose", no_argument, 0, 't'}, {"help", no_argument, 0, 'h'}, {0} }; for (int opt; (opt = getopt_long(argc, argv, "w:d:p:th", long_options)) != -1;) { switch (opt) { case 'w': options->width = (unsigned int)strtoul(optarg, NULL, 0); if (options->width % 8) { error_exit("Width not divisible by 8 px: %u\n", options->width); } break; case 'd': options->depth = (unsigned int)strtoul(optarg, NULL, 0); if (options->depth != 1 && options->depth != 2) { error_exit("Depth is not 1 or 2: %u\n", options->depth); } break; case 'p': options->palette = optarg; break; case 't': options->transpose = true; break; case 'h': usage_exit(0); break; default: usage_exit(1); } } } bool is_1bpp(const char *filename) { const char *end = strrchr(filename, '.'); return end && strlen(end) == 5 && end[1] == '1' && (end[2] == 'b' || end[2] == 'B') && (end[3] == 'p' || end[3] == 'P') && (end[4] == 'p' || end[4] == 'P'); } uint8_t *extend_1bpp_to_2bpp(uint8_t *bpp_data, long *size) { *size *= 2; bpp_data = xrealloc(bpp_data, *size); for (long i = *size - 2; i >= 0; i -= 2) { bpp_data[i] = bpp_data[i + 1] = bpp_data[i >> 1]; } return bpp_data; } void mingle_2bpp_planes(uint8_t *bpp_data, long size) { for (long i = 0; i < size; i += 2) { // Interleave aka "mingle" bits // <https://graphics.stanford.edu/~seander/bithacks.html#Interleave64bitOps> #define EXPAND_PLANE(b) (((((b) * 0x0101010101010101ULL & 0x8040201008040201ULL) * 0x0102040810204081ULL) >> 48) & 0xAAAA) uint16_t r = (EXPAND_PLANE(bpp_data[i]) >> 1) | EXPAND_PLANE(bpp_data[i + 1]); bpp_data[i] = r >> 8; bpp_data[i + 1] = r & 0xff; } } unsigned int calculate_size(long bytes, unsigned int *width) { long pixels = bytes * 4; if (pixels % (8 * 8)) { return 0; } if (!*width) { // If no width is specified, try to guess an appropriate one #define GUESS_SIZE(w, h) pixels == (w) * (h) * 8 * 8 ? (w) * 8 *width = GUESS_SIZE(5, 5) // mon pic : GUESS_SIZE(6, 6) // mon front/back pic : GUESS_SIZE(7, 7) // mon/trainer pic : GUESS_SIZE(2, 4) // mon icon : GUESS_SIZE(2, 12) // walking sprite : GUESS_SIZE(2, 6) // standing sprite : GUESS_SIZE(2, 2) // still sprite : GUESS_SIZE(4, 4) // big sprite : pixels > 16 * 8 * 8 ? 16 * 8 // maximum width : (unsigned int)(pixels / 8); } unsigned int height = (unsigned int)((pixels + *width * 8 - 1) / (*width * 8) * 8); if (*width == 0 || height == 0) { error_exit("Not divisible into 8x8-px tiles: %ux%u\n", *width, height); } return height; } uint8_t *pad_to_rectangle(uint8_t *bpp_data, long filesize, unsigned int width, unsigned int height) { unsigned int size = width * height / 4; if (size > filesize) { bpp_data = xrealloc(bpp_data, size); // Fill padding with white memset(bpp_data + filesize, 0, size - filesize); } return bpp_data; } uint8_t *transpose_tiles(uint8_t *bpp_data, unsigned int width, unsigned int height) { unsigned int size = width * height / 4; uint8_t *transposed = xmalloc(size); unsigned int cols = width / 8; for (unsigned int i = 0; i < size; i++) { unsigned int j = (i / 0x10) * cols * 0x10; j = (j % size) + 0x10 * (j / size) + (i % 0x10); transposed[j] = bpp_data[i]; } free(bpp_data); return transposed; } uint8_t *rearrange_tiles_to_scanlines(uint8_t *bpp_data, unsigned int width, unsigned int height) { unsigned int size = width * height / 4; uint8_t *rearranged = xmalloc(size); unsigned int cols = width / 8; unsigned int j = 0; for (unsigned int line = 0; line < height; line++) { unsigned int row = line / 8; for (unsigned int col = 0; col < cols; col++) { unsigned int i = ((row * cols + col) * 8 + line % 8) * 2; rearranged[j] = bpp_data[i]; rearranged[j + 1] = bpp_data[i + 1]; j += 2; } } free(bpp_data); return rearranged; } void read_gbcpal(Palette palette, const char *filename) { long filesize; uint8_t *pal_data = read_u8(filename, &filesize); if (filesize != 4 * 2) { error_exit("Invalid .gbcpal file: \"%s\"\n", filename); } for (int i = 0; i < 4; i++) { uint8_t b1 = pal_data[i * 2], b2 = pal_data[i * 2 + 1]; #define RGB5_TO_RGB8(x) (uint8_t)(((x) << 3) | ((x) >> 2)) palette[i][0] = RGB5_TO_RGB8(b1 & 0x1f); // red palette[i][1] = RGB5_TO_RGB8(((b1 & 0xe0) >> 5) | ((b2 & 0x03) << 3)); // green palette[i][2] = RGB5_TO_RGB8((b2 & 0x7c) >> 2); // blue } free(pal_data); } unsigned int write_png(const char *filename, uint8_t *bpp_data, unsigned int width, unsigned int height, Palette palette) { LodePNGState state; lodepng_state_init(&state); state.info_raw.bitdepth = state.info_png.color.bitdepth = 2; if (palette) { state.info_raw.colortype = state.info_png.color.colortype = LCT_PALETTE; for (int i = 0; i < 4; i++) { uint8_t *color = palette[i]; lodepng_palette_add(&state.info_raw, color[0], color[1], color[2], 0xff); lodepng_palette_add(&state.info_png.color, color[0], color[1], color[2], 0xff); } } else { state.info_raw.colortype = state.info_png.color.colortype = LCT_GREY; // 2-bit PNG white/light/dark/gray indexes are the inverse of 2bpp for (unsigned int i = 0; i < width * height / 4; i++) { bpp_data[i] = ~bpp_data[i]; } } unsigned char *buffer; size_t buffer_size; lodepng_encode(&buffer, &buffer_size, bpp_data, width, height, &state); unsigned int error = state.error; lodepng_state_cleanup(&state); if (!error) { error = lodepng_save_file(buffer, buffer_size, filename); } free(buffer); return error; } int main(int argc, char *argv[]) { struct Options options = {0}; parse_args(argc, argv, &options); argc -= optind; argv += optind; if (argc != 2) { usage_exit(1); } Palette palette = {0}; if (options.palette) { read_gbcpal(palette, options.palette); } const char *bpp_filename = argv[0]; long filesize; uint8_t *bpp_data = read_u8(bpp_filename, &filesize); if (!options.depth) { options.depth = is_1bpp(bpp_filename) ? 1 : 2; } if (!filesize || filesize % (8 * options.depth)) { error_exit("Invalid .%dbpp file: \"%s\"\n", options.depth, bpp_filename); } if (options.depth == 1) { bpp_data = extend_1bpp_to_2bpp(bpp_data, &filesize); } mingle_2bpp_planes(bpp_data, filesize); unsigned int height = calculate_size(filesize, &options.width); bpp_data = pad_to_rectangle(bpp_data, filesize, options.width, height); if (options.transpose) { bpp_data = transpose_tiles(bpp_data, options.width, height); } bpp_data = rearrange_tiles_to_scanlines(bpp_data, options.width, height); const char *png_filename = argv[1]; unsigned int error = write_png(png_filename, bpp_data, options.width, height, options.palette ? palette : NULL); if (error) { error_exit("Could not write to file \"%s\": %s\n", png_filename, lodepng_error_text(error)); } free(bpp_data); return 0; }