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#include "base.h"
#include "text.h"
#define STB_TRUETYPE_IMPLEMENTATION
#define STBTT_STATIC
no_warn_start
#include "stb_truetype.h"
no_warn_end
#include <stdarg.h>
#include <stdlib.h>
#include <GL/gl.h>
struct Font {
float char_height;
GLuint texture;
u32 nchars;
stbtt_bakedchar chars[];
};
static char text_err[200];
static void text_clear_err(void) {
text_err[0] = '\0';
}
static bool text_has_err(void) {
return text_err[0] != '\0';
}
char const *text_get_err(void) {
return text_err;
}
static void text_set_err(char const *fmt, ...) {
if (!text_has_err()) {
va_list args;
va_start(args, fmt);
vsnprintf(text_err, sizeof text_err - 1, fmt, args);
va_end(args);
}
}
Font *text_font_load(char const *ttf_filename, float font_size) {
Font *font = NULL;
u32 nchars = 128;
FILE *ttf_file = fopen(ttf_filename, "rb");
text_clear_err();
if (ttf_file) {
fseek(ttf_file, 0, SEEK_END);
u32 file_size = (u32)ftell(ttf_file);
if (file_size < (50UL<<20)) { // fonts aren't usually bigger than 50 MB
u8 *file_data = calloc(1, file_size);
font = calloc(1, sizeof *font + nchars * sizeof *font->chars);
if (file_data && font) {
if (fread(file_data, 1, file_size, ttf_file) == file_size) {
font->nchars = nchars;
font->char_height = font_size;
for (int bitmap_width = 256, bitmap_height = 256; bitmap_width <= 4096; bitmap_width *= 2, bitmap_height *= 2) {
u8 *bitmap = calloc((size_t)bitmap_width, (size_t)bitmap_height);
if (bitmap) {
int err = stbtt_BakeFontBitmap(file_data, 0, font->char_height, bitmap,
bitmap_width, bitmap_height, 0, (int)font->nchars, font->chars);
if (err > 0) {
// font converted to bitmap successfully.
GLuint texture = 0;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, bitmap_width, bitmap_height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, bitmap);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
#if DEBUG
debug_println("Loaded font %s with %dx%d bitmap.", ttf_filename, bitmap_width, bitmap_height);
#endif
font->texture = texture;
if (glGetError()) {
text_set_err("Couldn't create texture for font.");
}
}
} else {
text_set_err("Not enough memory for font bitmap.");
}
free(bitmap);
if (font->texture) { // if font loaded successfully
break;
}
}
if (!font->texture && !text_has_err()) {
text_set_err("Couldn't convert font to bitmap.");
}
} else {
text_set_err("Couldn't read font file.", ttf_filename);
}
} else {
text_set_err("Not enough memory for font.");
}
free(file_data);
if (text_has_err()) {
free(font);
font = NULL;
}
fclose(ttf_file);
} else {
text_set_err("Font file too big (%u megabytes).", (uint)(file_size >> 20));
}
} else {
text_set_err("Couldn't open font file.", ttf_filename);
}
return font;
}
#if 0
void text_render(Font *font, char const *text, float x, float y) {
}
void text_get_size(Font *font, char const *text, float *width, float *height) {
}
#endif
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