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#include "../../include/mgl/graphics/font.h"
#include "../../include/mgl/system/fileutils.h"
#include <stdio.h>
#define STB_RECT_PACK_IMPLEMENTATION
#include "../../external/stb_rect_pack.h"
#define STB_TRUETYPE_IMPLEMENTATION
#include "../../external/stb_truetype.h"
/* TODO: Test and fix .tcc files */
static unsigned int to_div2_ceil(unsigned int value) {
const uint32_t v = value;
return v + (v & 1);
}
int mgl_font_load_from_file(mgl_font *self, const char *filepath, unsigned int character_size) {
self->texture.id = 0;
self->font_atlas.atlas = NULL;
self->font_atlas.width = 0;
self->font_atlas.height = 0;
self->character_size = character_size;
self->packed_chars = NULL;
self->num_packed_chars = 0;
mgl_memory_mapped_file mapped_file;
if(mgl_mapped_file_load(filepath, &mapped_file, &(mgl_memory_mapped_file_load_options){ .readable = true, .writable = false }) != 0) {
fprintf(stderr, "Error: failed to load font %s, error: mgl_load_file failed\n", filepath);
return -1;
}
stbtt_fontinfo font;
if(!stbtt_InitFont(&font, mapped_file.data, stbtt_GetFontOffsetForIndex(mapped_file.data, 0))) {
fprintf(stderr, "Error: failed to load font %s, error: stbtt_InitFont failed\n", filepath);
mgl_mapped_file_unload(&mapped_file);
return -1;
}
self->num_packed_chars = 256;
self->packed_chars = malloc(self->num_packed_chars * sizeof(stbtt_packedchar));
if(!self->packed_chars) {
fprintf(stderr, "Error: failed to load font %s, error: out of memory\n", filepath);
goto error;
}
bool atlas_created = false;
/* TODO: Optimize */
/* Find optimal size for atlas, starting from small to large */
for(int i = 0; i < 4; ++i) {
/*
This to_div2_ceil is needed because otherwise for character sizes such as 33 which are not divisable by 2
causes the font texture to be skewed. I dont know why this happens. Maybe a bug in stbtt?
TODO: Figure out why it happens.
*/
self->font_atlas.width = (14 + (8 * i)) * to_div2_ceil(self->character_size);
self->font_atlas.height = (14 + (8 * i)) * to_div2_ceil(self->character_size);
unsigned char *new_atlas = realloc(self->font_atlas.atlas, self->font_atlas.width * self->font_atlas.height);
if(!new_atlas) {
fprintf(stderr, "Error: failed to load font %s, error: out of memory\n", filepath);
goto error;
}
self->font_atlas.atlas = new_atlas;
stbtt_pack_context pc;
if(!stbtt_PackBegin(&pc, self->font_atlas.atlas, self->font_atlas.width, self->font_atlas.height, self->font_atlas.width, 1, NULL)) {
fprintf(stderr, "Error: failed to load font %s, error: stbtt_PackBegin failed\n", filepath);
goto error;
}
stbtt_PackSetOversampling(&pc, 2, 2);
if(!stbtt_PackFontRange(&pc, mapped_file.data, 0, self->character_size, 0, self->num_packed_chars, self->packed_chars)) {
stbtt_PackEnd(&pc);
continue;
}
/*if(!stbtt_PackFontRange(&pc, mapped_file.data, 0, self->character_size, 0x00004E00, self->num_packed_chars, self->packed_chars)) {
stbtt_PackEnd(&pc);
continue;
}*/
stbtt_PackEnd(&pc);
atlas_created = true;
break;
}
if(!atlas_created) {
fprintf(stderr, "Error: failed to load font %s, error: failed to create atlas\n", filepath);
goto error;
}
if(mgl_texture_load_from_memory(&self->texture, self->font_atlas.atlas, self->font_atlas.width, self->font_atlas.height, MGL_IMAGE_FORMAT_ALPHA, NULL) != 0) {
fprintf(stderr, "Error: failed to load font %s, error: mgl_texture_load_from_memory failed\n", filepath);
goto error;
}
/* TODO: Use stbtt_GetCodepointSDF */
mgl_mapped_file_unload(&mapped_file);
return 0;
error:
mgl_mapped_file_unload(&mapped_file);
mgl_font_unload(self);
return -1;
}
void mgl_font_unload(mgl_font *self) {
mgl_texture_unload(&self->texture);
free(self->font_atlas.atlas);
self->font_atlas.atlas = NULL;
self->font_atlas.width = 0;
self->font_atlas.height = 0;
free(self->packed_chars);
self->packed_chars = NULL;
self->num_packed_chars = 0;
}
int mgl_font_get_glyph(const mgl_font *self, uint32_t codepoint, mgl_font_glyph *glyph) {
stbtt_packedchar *packed_chars = self->packed_chars;
if(codepoint < 0 || codepoint >= 0 + self->num_packed_chars)
return -1;
float x = 0.0f;
float y = 0.0f;
stbtt_aligned_quad quad;
stbtt_GetPackedQuad(packed_chars, self->font_atlas.width, self->font_atlas.height, codepoint, &x, &y, &quad, 0);
glyph->position = (mgl_vec2f){ quad.x0, quad.y0 };
glyph->size = (mgl_vec2f){ quad.x1 - quad.x0, quad.y1 - quad.y0 };
glyph->texture_position = (mgl_vec2f){ quad.s0, quad.t0 };
glyph->texture_size = (mgl_vec2f){ quad.s1 - quad.s0, quad.t1 - quad.t0 };
glyph->advance = x;
return 0;
}
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