.fnt fonts¶

The interface's text is drawn with WinVFX bitmap fonts, loaded from resource.hog.

sltool fnt info <font>                # header, and the width of every character
sltool fnt render <font> <out.png>    # every glyph in one atlas, sixteen codes to a row
make fonts                            # every font into game/fonts

Layout¶

The table is indexed by character code. A glyph is a u32 width, then width x height bytes of pixels, row by row. Glyphs follow the table in code order, and a glyph of width 0 is four bytes.

Some fonts end with 768 more bytes: 256 RGB triples of 6-bit levels. In some it is a grey ramp, in others unrelated colours. Unknown: what reads it; neither WinVFX nor the payload's font setup does.

Pixels¶

A pixel is a coverage level, 0 for none up to 16 for fully inked, so glyphs are anti-aliased. WinVFX's VFX_character_draw either writes the levels as they are or looks each up in a remap table the caller supplies, with 0xFF meaning transparent; the remap table is what gives text its colour. sltool fnt render shows the levels as grey, with 0 transparent.

Characters¶

Codes 0 to 31 are empty. Codes 32 to 127 are ASCII, and in the larger fonts 128 to 255 hold accented letters and symbols. Some tables run past 255, but those entries are empty, and the payload's font setup, font_open (0x00480D70), caches the width of codes below 255 only.

Outline fonts¶

OpenReliant draws the interface text with outline fonts at the window's resolution, instead of scaling up the bitmap fonts (hud/outline.zig). FreeType renders the glyphs (Platform).

• Which font. A TrueType or OpenType font in a mod with the same name as a bitmap font replaces it: optfnt.ttf or optfnt.otf for interface\optfnt.fnt, with the TrueType font tried first (Modding). Otherwise Newtown, which is built into OpenReliant (deps/newtown), replaces the original Handel Gothic fonts: optfnt.fnt and smlfnt2.fnt, the large and small menu fonts; itacbig.fnt and itacsml.fnt, the ITAC fonts; blufont.fnt, the flight display font; and ld_handel.fnt, the loadout tooltip font. A .fnt file in a mod is drawn from its bitmaps.
• Palette fonts. The flight display font and the loadout tooltip font are drawn through a palette, with each pixel of a glyph in its own colour. For these fonts, the ink is the brightest colour their digits and letters use, and each colour counts as partial coverage by how close it is to the ink, since the bitmap's pixels fade towards black where the glyph covers them less. Outline glyphs are drawn in the ink colour, and a glyph that uses colours the digits and letters don't use, such as a symbol, keeps its bitmap.
• Weight. Newtown's strokes are made as heavy as the bitmap font's. OpenReliant makes them wider or narrower (FreeType's FT_Outline_Embolden) until its digits and letters, drawn at eight times the size with capitals of the same height, cover as many pixels as the bitmap font's. The first estimate of the change is the missing coverage divided by half the length of the glyphs' edges, and OpenReliant repeats the estimate from the result until it settles. A mod's font is drawn at its normal weight.
• Outline. VFX draws every pixel of a bitmap glyph that has any coverage as fully opaque, blending the ink colour with black by how much the glyph covers it, so the original text has a dark edge wherever the background is lighter. An outline glyph's pixels are only as opaque as they are covered, so OpenReliant gives the text a black outline one bitmap pixel wide instead: before it draws a line of text, it draws each glyph eight times in black, offset in the eight compass directions.
• Layout. The text keeps the bitmap font's layout: each character's width and the line height come from the bitmap font, so every screen lays out its text like the original. Each character is drawn from the outline font at the size that makes its capitals as tall as the bitmap font's, measured on the first of H, I, E, F, L and T that both fonts have. It sits on the bitmap font's baseline, the bottom of that letter's ink, and is centred on the inked part of the bitmap glyph. Ink is measured to a fraction of a pixel: a pixel half covered at the edge of the ink puts the edge halfway into the pixel. A character the outline font has no glyph for keeps the bitmap glyph, and a character whose bitmap glyph has no ink draws nothing. Characters are in the game's code page, 1252.
• Pixels. Each size of a font is rendered once into a texture, in white with each pixel's alpha set by its coverage, and the text colour tints it. Each glyph is drawn aligned to the window's pixels, so the text is as sharp as the window's resolution allows. FreeType's light hinting fits the glyphs' heights to the pixel grid.

Improvement: the original draws its text with its bitmap fonts at 640x480. --bitmap-fonts, --original and the OUTLINE FONTS setting draw the bitmap fonts instead, scaled up, with opaque pixels as VFX draws them.

Prior art¶

DMJC's StarLanceDecomp read the header, the glyph records and the two drawing modes from WINVFX8.DLL. It gives the offset table a fixed 256 entries; the table's length is the count at 0x04, which in several fonts exceeds 256. The trailing palette and the coverage levels are additions.