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#include "font.h"
#include <assert.h>
#include <stdlib.h>
/* Create a texture atlas containing all of the glyphs in a font. */
SDL_Texture *font_create_texture(SDL_Renderer *renderer, PSFFont *font)
{
SDL_Texture *result;
const int texture_width = font->num_glyphs * font->width;
const int bits_per_glyph = 8;
SDL_Surface *surface = SDL_CreateRGBSurface(0, texture_width, font->height, 32, 0, 0, 0, 0);
for (int glyph_idx = 0; glyph_idx < font->num_glyphs; glyph_idx++) {
for (int y = 0; y < font->height; y++) {
for (int x = 0; x < font->width; x++) {
/*
* TODO: Make it possible for the texture atlas to have more
* than one row.
*/
int xp = x + glyph_idx * bits_per_glyph;
int yp = y;
int bit_idx = 8 - 1 - x;
char current_bit = font->glyph_data[glyph_idx * font->bytes_per_glyph + y] & (1 << bit_idx);
((Uint32*)(surface->pixels))[xp + yp * surface->w] = current_bit ? 0xffffffff : 0;
}
}
}
result = SDL_CreateTextureFromSurface(renderer, surface);
if (result == NULL) {
fprintf(stderr, "Failed to create texture: %s\n", SDL_GetError());
}
SDL_FreeSurface(surface);
printf("Created font texture atlas of size %dx%d\n", surface->w, surface->h);
return result;
}
PSFFont font_load(const char *filename)
{
PSFFont font;
FILE *fp = fopen(filename, "rb");
fread(&font.magic, 4, 1, fp);
assert(font.magic == PSF_MAGIC_NUMBER);
fread(&font.version, 4, 1, fp);
fread(&font.header_size, 4, 1, fp);
fread(&font.flags, 4, 1, fp);
fread(&font.num_glyphs, 4, 1, fp);
fread(&font.bytes_per_glyph, 4, 1, fp);
fread(&font.height, 4, 1, fp);
fread(&font.width, 4, 1, fp);
/* TODO: Implement unicode translation table. */
size_t glyph_buffer_size = font.num_glyphs * font.bytes_per_glyph;
font.glyph_data = malloc(glyph_buffer_size);
fread(font.glyph_data, font.bytes_per_glyph, font.num_glyphs, fp);
fclose(fp);
printf("Loaded a font with %d glyphs of size %dx%d (%d bytes per glyph)\n",
font.num_glyphs, font.width, font.height, font.bytes_per_glyph);
return font;
}
void font_destroy(PSFFont *font)
{
free(font->glyph_data);
}
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