quakeforge/libs/video/renderer/r_font.c
Bill Currie 534d5367de [vulkan] Use linear sampling for glyphs
This requires having padding around the glyphs to avoid texel leak, but
as the atlas is created at runtime, it's possible to get the padding in.
2022-11-20 03:59:01 +09:00

136 lines
3.6 KiB
C

/*
r_font.c
Renderer font management management
Copyright (C) 2022 Bill Currie <bill@taniwha.org>
Author: Bill Currie <bill@taniwha.org>
Date: 2022/8/26
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to:
Free Software Foundation, Inc.
59 Temple Place - Suite 330
Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <math.h>
#include "QF/quakefs.h"
#include "QF/sys.h"
#include "QF/math/bitop.h"
#include "r_font.h"
#include "compat.h"
static FT_Library ft;
static void
copy_glyph (vrect_t *rect, FT_GlyphSlot src_glyph, rfont_t *font)
{
int dst_pitch = font->scrap.width;
byte *dst = font->scrap_bitmap + rect->x + rect->y * dst_pitch;
int src_pitch = src_glyph->bitmap.pitch;
byte *src = src_glyph->bitmap.buffer;
for (unsigned i = 0; i < src_glyph->bitmap.rows; i++) {
memcpy (dst, src, src_glyph->bitmap.width);
dst += dst_pitch;
src += src_pitch;
}
}
VISIBLE void
R_FontInit (void)
{
if (FT_Init_FreeType (&ft)) {
Sys_Error ("Could not init FreeType library");
}
}
VISIBLE void
R_FontFree (rfont_t *font)
{
if (font->face) {
FT_Done_Face (font->face);
}
if (font->scrap.rects || font->scrap.free_rects) {
R_ScrapDelete (&font->scrap);
}
free (font->glyph_rects);
free (font->glyph_bearings);
free (font->scrap_bitmap);
free (font->font_resource);
free (font);
}
VISIBLE rfont_t *
R_FontLoad (QFile *font_file, int size)
{
byte *font_data = QFS_LoadFile (font_file, 0);
if (!font_data) {
return 0;
}
size_t font_size = qfs_filesize;
rfont_t *font = calloc (1, sizeof (rfont_t));
font->font_resource = font_data;
if (FT_New_Memory_Face (ft, font_data, font_size, 0, &font->face)) {
R_FontFree (font);
return 0;
}
FT_Set_Pixel_Sizes(font->face, 0, size);
int pixels = 0;
for (FT_Long gind = 0; gind < font->face->num_glyphs; gind++) {
FT_Load_Glyph (font->face, gind, FT_LOAD_DEFAULT);
__auto_type g = font->face->glyph;
// include padding around the glyph to avoid texel leaks
pixels += (g->bitmap.width + 1) * (g->bitmap.rows + 1);
}
pixels = sqrt (5 * pixels / 4);
pixels = BITOP_RUP (pixels);
R_ScrapInit (&font->scrap, pixels, pixels);
font->scrap_bitmap = calloc (1, pixels * pixels);
font->num_glyphs = font->face->num_glyphs;
font->glyph_rects = malloc (font->num_glyphs * sizeof (vrect_t));
font->glyph_bearings = malloc (font->num_glyphs * sizeof (vec2i_t));
for (FT_Long gind = 0; gind < font->face->num_glyphs; gind++) {
vrect_t *rect = &font->glyph_rects[gind];
vec2i_t *bearing = &font->glyph_bearings[gind];
FT_Load_Glyph (font->face, gind, FT_LOAD_DEFAULT);
__auto_type slot = font->face->glyph;
FT_Render_Glyph (slot, FT_RENDER_MODE_NORMAL);
// add padding to create a buffer around the glyph to prevent texel
// leaks
int width = slot->bitmap.width + 1;
int height = slot->bitmap.rows + 1;
*rect = *R_ScrapAlloc (&font->scrap, width, height);
*bearing = (vec2i_t) { slot->bitmap_left, slot->bitmap_top };
// shrink the rect so as to NOT include the padding
rect->width -= 1;
rect->height -= 1;
copy_glyph (rect, slot, font);
}
return font;
}