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#include <SDL2/SDL.h>
#include <stdio.h>
#include <stdlib.h>
typedef struct {
int code_point;
SDL_Point next_glyph_offset;
SDL_Rect bounds;
char *bitmap;
int bitmap_size;
} BDFFontChar;
typedef struct {
SDL_Rect bounds;
BDFFontChar *chars;
int num_chars;
int char_index_for_code_point[128];
} BDFFontInfo;
/* Create a texture containing all of the glyphs in a specified BDF file. */
SDL_Texture *bdf_create_texture(SDL_Renderer *renderer, BDFFontInfo *font)
{
SDL_Texture *result;
SDL_Surface *surface = SDL_CreateRGBSurface(0, 8 * font->num_chars, font->bounds.h, 32, 0, 0, 0, 0);
printf("Made surface of size %dx%d\n", surface->w, surface->h);
SDL_LockSurface(surface);
for (int i = 0; i < font->num_chars; i++) {
BDFFontChar chair = font->chars[i];
for (int y = 0; y < font->bounds.h; y++) {
int bits_for_row = chair.bitmap[y];
for (int x = 0; x < 8; x++) {
int bit_index = 7 - x;
int current_bit = bits_for_row & (1 << bit_index);
int xp = x + i * 8;
int yp = y;
((Uint32*)(surface->pixels))[xp + yp * surface->w] = current_bit ? 0xffffffff : 0;
}
}
}
SDL_UnlockSurface(surface);
result = SDL_CreateTextureFromSurface(renderer, surface);
if (result == NULL) {
fprintf(stderr, "Failed to create texture: %s\n", SDL_GetError());
}
SDL_FreeSurface(surface);
return result;
}
/*
* Loads a BDF font file into a data structure.
* TODO: This is extremely atrocious!
*/
BDFFontInfo bdf_read_font(const char *filename)
{
FILE *fp;
char *line = NULL;
size_t len = 0;
ssize_t bytes_read;
BDFFontInfo result;
result.bounds.x = 0;
result.bounds.y = 0;
result.bounds.w = 0;
result.bounds.h = 0;
result.chars = NULL;
result.num_chars = 0;
fp = fopen(filename, "r");
if (fp == NULL) {
fprintf(stderr, "Failed to open file from %s\n", filename);
return;
}
int is_reading_bitmap = 0;
int char_counter = -1;
while ((bytes_read = getline(&line, &len, fp)) != -1) {
if (strncmp(line, "FONTBOUNDINGBOX", 15) == 0) {
sscanf(line, "FONTBOUNDINGBOX %d %d %d %d\n", &result.bounds.w,
&result.bounds.h,
&result.bounds.x,
&result.bounds.y);
}
if (strncmp(line, "CHARS", 5) == 0) {
sscanf(line, "CHARS %d\n", &result.num_chars);
result.chars = malloc(result.num_chars * sizeof(BDFFontChar));
}
if (strncmp(line, "STARTCHAR", 9) == 0) {
char_counter++;
result.chars[char_counter].code_point = 0;
result.chars[char_counter].next_glyph_offset.x = 0;
result.chars[char_counter].next_glyph_offset.y = 0;
result.chars[char_counter].bounds.x = 0;
result.chars[char_counter].bounds.y = 0;
result.chars[char_counter].bounds.w = 0;
result.chars[char_counter].bounds.h = 0;
result.chars[char_counter].bitmap = NULL;
result.chars[char_counter].bitmap_size = 0;
}
if (strncmp(line, "ENCODING", 8) == 0) {
int code_point = 0;
sscanf(line, "ENCODING %d\n", &code_point);
if (code_point < 256)
result.char_index_for_code_point[code_point] = char_counter;
result.chars[char_counter].code_point = code_point;
}
if (strncmp(line, "DWIDTH", 6) == 0) {
sscanf(line, "DWIDTH %d %d\n", &result.chars[char_counter].next_glyph_offset.x,
&result.chars[char_counter].next_glyph_offset.y);
}
if (strncmp(line, "BBX", 3) == 0) {
sscanf(line, "BBX %d %d %d %d\n", &result.chars[char_counter].bounds.w,
&result.chars[char_counter].bounds.h,
&result.chars[char_counter].bounds.x,
&result.chars[char_counter].bounds.y);
result.chars[char_counter].bounds.x += char_counter * 8;
result.chars[char_counter].bounds.y = -result.chars[char_counter].bounds.y;
}
if (strncmp(line, "BITMAP", 6) == 0) {
is_reading_bitmap = 1;
}
if (is_reading_bitmap) {
if (strncmp(line, "ENDCHAR", 7) == 0) {
is_reading_bitmap = 0;
continue;
}
BDFFontChar *chair = &result.chars[char_counter];
chair->bitmap = realloc(chair->bitmap, chair->bitmap_size++);
chair->bitmap[chair->bitmap_size - 1] = strtol(line, NULL, 16);
}
}
fclose(fp);
if (line) { free(line); }
return result;
}
BDFFontChar bdf_char_by_code_point(BDFFontInfo *font, int code_point)
{
for (int i = 0; i < font->num_chars; i++)
if (font->chars[i].code_point == code_point)
return font->chars[i];
}
int main(int argc, char **argv)
{
SDL_Window *window = NULL;
SDL_Renderer *renderer = NULL;
BDFFontInfo font = bdf_read_font("ter-u12n.bdf");
printf("Loaded font with %d chars, width %d\n", font.num_chars, font.bounds.w);
if (SDL_Init(SDL_INIT_VIDEO) != 0) {
fprintf(stderr, "Failed to initalize SDL: %s\n", SDL_GetError());
return 1;
}
window = SDL_CreateWindow("Bitmap font test", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
640, 480, SDL_WINDOW_SHOWN);
if (window == NULL) {
fprintf(stderr, "Failed to create a window: %s\n", SDL_GetError());
return 1;
}
renderer = SDL_CreateRenderer(window, -1, 0);
if (renderer == NULL) {
fprintf(stderr, "Failed to create a renderer: %s\n", SDL_GetError());
return 1;
}
SDL_Texture *font_texture = bdf_create_texture(renderer, &font);
SDL_ShowWindow(window);
const char *testmsg = "Hello, welcome to the bitmap font test!";
int is_running = 1;
while (is_running) {
static SDL_Event e;
while (SDL_PollEvent(&e)) {
switch (e.type) {
case SDL_QUIT:
is_running = 0;
break;
}
}
SDL_RenderClear(renderer);
SDL_Rect dstrect = { 0, 0, 0, 0 };
for (int i = 0; i < strlen(testmsg); i++) {
const char letter = testmsg[i];
const int char_index = font.char_index_for_code_point[letter];
BDFFontChar *glyph = &font.chars[char_index];
dstrect.w = glyph->bounds.w;
dstrect.h = glyph->bounds.h;
SDL_RenderCopy(renderer, font_texture, &glyph->bounds, &dstrect);
dstrect.x += glyph->next_glyph_offset.x;
dstrect.y += glyph->next_glyph_offset.y;
}
SDL_RenderPresent(renderer);
SDL_UpdateWindowSurface(window);
}
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}
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