1 files changed, 179 insertions, 0 deletions
diff --git a/src/font/genatlas.cpp b/src/font/genatlas.cpp
new file mode 100644
index 0000000..def571d
--- /dev/null
+++ b/src/font/genatlas.cpp
@@ -0,0 +1,179 @@
+#define STB_TRUETYPE_IMPLEMENTATION
+#include "stb_truetype.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static const int iso8859_2_to_utf32[256] = {
+    0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 
+    0x0008, 0x0009, 0x000A, 0x000B, 0x000C, 0x000D, 0x000E, 0x000F, 
+    0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017, 
+    0x0018, 0x0019, 0x001A, 0x001B, 0x001C, 0x001D, 0x001E, 0x001F, 
+    0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027, 
+    0x0028, 0x0029, 0x002A, 0x002B, 0x002C, 0x002D, 0x002E, 0x002F, 
+    0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037, 
+    0x0038, 0x0039, 0x003A, 0x003B, 0x003C, 0x003D, 0x003E, 0x003F, 
+    0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047, 
+    0x0048, 0x0049, 0x004A, 0x004B, 0x004C, 0x004D, 0x004E, 0x004F, 
+    0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, 
+    0x0058, 0x0059, 0x005A, 0x005B, 0x005C, 0x005D, 0x005E, 0x005F, 
+    0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067, 
+    0x0068, 0x0069, 0x006A, 0x006B, 0x006C, 0x006D, 0x006E, 0x006F, 
+    0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077, 
+    0x0078, 0x0079, 0x007A, 0x007B, 0x007C, 0x007D, 0x007E, 0x007F, 
+    0x0080, 0x0081, 0x0082, 0x0083, 0x0084, 0x0085, 0x0086, 0x0087, 
+    0x0088, 0x0089, 0x008A, 0x008B, 0x008C, 0x008D, 0x008E, 0x008F, 
+    0x0090, 0x0091, 0x0092, 0x0093, 0x0094, 0x0095, 0x0096, 0x0097, 
+    0x0098, 0x0099, 0x009A, 0x009B, 0x009C, 0x009D, 0x009E, 0x009F, 
+    0x00A0, 0x0104, 0x02D8, 0x0141, 0x00A4, 0x013D, 0x015A, 0x00A7, 
+    0x00A8, 0x0160, 0x015E, 0x0164, 0x0179, 0x00AD, 0x017D, 0x017B, 
+    0x00B0, 0x0105, 0x02DB, 0x0142, 0x00B4, 0x013E, 0x015B, 0x02C7, 
+    0x00B8, 0x0161, 0x015F, 0x0165, 0x017A, 0x02DD, 0x017E, 0x017C, 
+    0x0154, 0x00C1, 0x00C2, 0x0102, 0x00C4, 0x0139, 0x0106, 0x00C7, 
+    0x010C, 0x00C9, 0x0118, 0x00CB, 0x011A, 0x00CD, 0x00CE, 0x010E, 
+    0x0110, 0x0143, 0x0147, 0x00D3, 0x00D4, 0x0150, 0x00D6, 0x00D7, 
+    0x0158, 0x016E, 0x00DA, 0x0170, 0x00DC, 0x00DD, 0x0162, 0x00DF, 
+    0x0155, 0x00E1, 0x00E2, 0x0103, 0x00E4, 0x013A, 0x0107, 0x00E7, 
+    0x010D, 0x00E9, 0x0119, 0x00EB, 0x011B, 0x00ED, 0x00EE, 0x010F, 
+    0x0111, 0x0144, 0x0148, 0x00F3, 0x00F4, 0x0151, 0x00F6, 0x00F7, 
+    0x0159, 0x016F, 0x00FA, 0x0171, 0x00FC, 0x00FD, 0x0163, 0x02D9, 
+};
+
+#define CHAR_W 8
+#define CHAR_H 12
+#define EM_HEIGHT 8
+#define BASELINE 14
+
+typedef struct {
+    unsigned char data[12]; // each element is a row, bits are columns, LSB = leftmost
+    unsigned char width;
+} AtlasItem;
+
+void atlas_item_print(const AtlasItem *item) {
+    for (int y = 0; y < CHAR_H; y++) {
+        for (int x = 0; x < CHAR_W; x++) {
+            putchar((item->data[y] & (1 << x)) ? '@' : '.');
+        }
+        putchar('\n');
+    }
+    putchar('\n');
+}
+
+AtlasItem atlas_item_from_codepoint(stbtt_fontinfo *font, int codepoint) {
+    AtlasItem item = {0};
+
+    int w, h, xoff, yoff;
+
+    unsigned char *bitmap = stbtt_GetCodepointBitmap(
+        font,
+        0,
+        stbtt_ScaleForMappingEmToPixels(font, EM_HEIGHT),
+        codepoint,
+        &w,
+        &h,
+        &xoff,
+        &yoff
+    );
+
+    int out_w = w > CHAR_W ? CHAR_W : w;
+    int out_h = h > CHAR_H ? CHAR_H : h;
+
+    if (w > CHAR_W) printf("invalid width %d for glyph %lc\n",  w, codepoint);
+    if (h > CHAR_H) printf("invalid height %d for glyph %lc\n", h, codepoint);
+
+    int cell_y = BASELINE + yoff; // yoff is negative for above-baseline glyphs
+
+    for (int y = 0; y < out_h; y++) {
+        int dest_y = cell_y + y;
+        if (dest_y < 0 || dest_y >= CHAR_H) continue;
+        for (int x = 0; x < out_w; x++) {
+            if (bitmap[y * w + x] > 0x7F)
+                item.data[dest_y] |= (1 << x);
+        }
+    }
+
+    stbtt_FreeBitmap(bitmap, NULL);
+
+    item.width = (unsigned char)out_w;
+    return item;
+}
+
+char ttf_buffer[1 << 25];
+
+int main(int argc, char **argv)
+{
+    const char *font_name = argc > 1 ? argv[1] : "Minecraftia-Regular.ttf";
+
+    FILE *f = fopen(font_name, "rb");
+    if (!f) {
+        perror(font_name);
+        return 1;
+    }
+
+    fread(ttf_buffer, 1, sizeof(ttf_buffer), f);
+    fclose(f);
+
+    stbtt_fontinfo font;
+    stbtt_InitFont(
+        &font,
+        (unsigned char *)ttf_buffer,
+        stbtt_GetFontOffsetForIndex((unsigned char *)ttf_buffer, 0)
+    );
+
+    AtlasItem result[256];
+
+    for (int i = 0; i < 256; i++) {
+        memset(&result[i].data, 0xFF, sizeof(result[i].data));
+        result[i].width = 8;
+    }
+
+    memset(&result[' '].data, 0x00, sizeof(result[' '].data));
+    result[' '].width = 2;
+
+    // printable ASCII
+    for (int i = 33; i < 127; i++) {
+        result[i] = atlas_item_from_codepoint(&font, i);
+    }
+
+    unsigned char polish_iso8859_2[] = {
+        // Ą,   Ć,   Ę,   Ł,   Ń,   Ó,   Ś,   Ź,   Ż,   ą,   ć,   ę,   ł,   ń,   ó,   ś,   ź,   ż
+           161, 198, 202, 163, 209, 211, 166, 172, 175, 177, 230, 234, 179, 241, 243, 182, 188, 191
+    };
+
+    // ISO-8859-2 slop
+    for (int i = 0; i < sizeof(polish_iso8859_2); i++) {
+        int actual_index = polish_iso8859_2[i];
+        result[actual_index] = atlas_item_from_codepoint(&font, iso8859_2_to_utf32[actual_index]);
+    }
+
+
+    FILE *out = fopen("../font_atlas.c", "w");
+
+    fprintf(out, "#include <stdint.h>\n\n");
+    fprintf(out, "#define FONT_CHAR_W 8\n");
+    fprintf(out, "#define FONT_CHAR_H 12\n\n");
+    fprintf(out, "typedef struct {\n");
+    fprintf(out, "    uint8_t data[12];\n");
+    fprintf(out, "    uint8_t width;\n");
+    fprintf(out, "} FontGlyph;\n\n");
+    fprintf(out, "static const FontGlyph font_glyphs[256] = {\n");
+
+    for (int i = 0; i < 256; i++) {
+        AtlasItem *it = &result[i];
+
+        char comment[16] = "";
+        if (i >= 33 && i < 127)
+            snprintf(comment, sizeof(comment), " /* '%c' */", (char)i);
+
+        fprintf(out, "    [0x%02X] =%s { {", i, comment);
+        for (int r = 0; r < CHAR_H; r++)
+            fprintf(out, "0x%02X%s", it->data[r], r < CHAR_H - 1 ? "," : "");
+        fprintf(out, "}, %d },\n", it->width);
+    }
+
+    fprintf(out, "};\n\n");
+    fclose(out);
+
+    return 0;
+}