ref: 02d957278da707dfea6ce02ab867f7e127d5a645
parent: 6feb1fb73a0c6e3127ab58f82d4673f3aba2c06c
author: ISSOtm <eldredhabert0@gmail.com>
date: Tue Apr 12 21:05:37 EDT 2022
Document output formats
--- a/man/rgbgfx.1
+++ b/man/rgbgfx.1
@@ -435,15 +435,37 @@
Since few image editors (such as GIMP) expose that detail, this behavior is only kept for compatibility and should be considered deprecated.
.Sh OUTPUT FILES
.Ss Tile data
-TODO.
+Tile data is output like a binary dump of VRAM, following the Game Boy's native format.
+Each tile is 16 bytes, 2 per row of 8 pixels; the first byte
+.Pq or Dq bitplane
+contains the least significant bit of the color ID of each pixel, the second one the most significant bit.
+The most significant bits of each byte are for the leftmost pixel of its row, and so on, with the least significant bits describing the rightmost pixel.
+.Pp
+When the bit depth
+.Pq Fl d
+is set to 1, every other byte (being all zeros) is simply not output.
.Ss Palette data
Palette data is output like a dump of GBC palette memory: the output is a binary file.
-Each color is written as GBC-native little-endian RGB555 (that is, the first byte contains the red and the lower 3 bits of green).
+Each color is written as GBC-native little-endian RGB555 (that is, the first byte contains the red and the lower 3 bits of green, and the second byte the upper 2 bits of green and the 5 bits of blue, plus an unused bit set to 0).
There is no padding between colors, nor between palettes; however, empty colors in the palettes are TODO.
-.Ss Tilemap data
-TODO.
-.Ss Attrmap data
-TODO.
+.Ss Tile map data
+Tile maps are output as binary files.
+A tile map is an array of tile IDs, with one byte per tile ID.
+The first byte always corresponds to the ID of the tile in top-left corner of the input image; the second byte is either the ID of the tile to its right (by default), or below it
+.Pq with Fl Z ;
+and so on.
+Rows / columns (respectively) are stored consecutively, with no padding.
+.Ss Attribute map data
+Attribute maps mirror the format of tile maps, like on the GBC, especially the order in which bytes are output.
+The contents of individual bytes follows the GBC's native format:
+.Bl -column "Bit 2\(en0" "Background Palette number"
+.It Bit 7 Ta BG-to-OAM Priority Ta Set to 0
+.It Bit 6 Ta Vertical Flip Ta 0=Normal, 1=Mirror vertically
+.It Bit 5 Ta Horizontal Flip Ta 0=Normal, 1=Mirror horizontally
+.It Bit 4 Ta Not used Ta Set to 0
+.It Bit 3 Ta Tile VRAM Bank number Ta 0=Bank 0, 1=Bank 1
+.It Bit 2\(en0 Ta Background Palette number Ta BGP0-7
+.El
.Sh REVERSE MODE
.Nm
can produce a PNG image from valid data.
@@ -527,6 +549,10 @@
.Xr rgblink 1 ,
.Xr rgbfix 1 ,
.Xr gbz80 7
+.Pp
+The Game Boy hardware reference
+.Lk https://gbdev.io/pandocs/Rendering.html Pan Docs ,
+particularly the section about graphics.
.Sh HISTORY
.Nm
was originally created by
--- a/src/gfx/main.cpp
+++ b/src/gfx/main.cpp
@@ -130,15 +130,15 @@
};
static void printUsage(void) {- fputs("Usage: rgbgfx [-r] [-CmuVZ] [-v [-v ...]] [-a <attr_map> | -A] [-b base_ids]\n"- " [-c color_spec] [-d <depth>] [-L slice] [-N nb_tiles] [-n nb_pals]\n"
- " [-o <out_file>] [-p <pal_file> | -P] [-s nb_colors] [-t <tile_map> | -T]\n"
- " [-U unit_size] [-x <tiles>] <file>\n"
+ fputs("Usage: rgbgfx [-r stride] [-CmuVZ] [-v [-v ...]] [-a <attr_map> | -A]\n"+ " [-b base_ids] [-c color_spec] [-d <depth>] [-L slice] [-N nb_tiles]\n"
+ " [-n nb_pals] [-o <out_file>] [-p <pal_file> | -P] [-s nb_colors]\n"
+ " [-t <tile_map> | -T] [-U unit_size] [-x <tiles>] <file>\n"
"Useful options:\n"
- " -m, --mirror-tiles optimize out mirrored tiles\n"
- " -o, --output <path> set the output binary file\n"
- " -t, --tilemap <path> set the output tilemap file\n"
- " -u, --unique-tiles optimize out identical tiles\n"
+ " -m, --mirror-tiles optimize out mirrored tiles\n"
+ " -o, --output <path> set the output binary file\n"
+ " -t, --tilemap <path> set the output tilemap file\n"
+ " -u, --unique-tiles optimize out identical tiles\n"
" -V, --version print RGBGFX version and exit\n"
"\n"
"For help, use `man rgbgfx' or go to https://rgbds.gbdev.io/docs/\n",