power_play/src/font/font_core.c

////////////////////////////////
//~ Load job

JobDef(F_LoadJob, sig, _)
{
    __prof;
    TempArena scratch = BeginScratchNoConflict();

    Readonly LocalPersist u32 font_codes[] = {
        0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,0x29,0x2A,0x2B,0x2C,0x2D,
        0x2E,0x2F,0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,
        0x3C,0x3D,0x3E,0x3F,0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,
        0x4A,0x4B,0x4C,0x4D,0x4E,0x4F,0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,
        0x58,0x59,0x5A,0x5B,0x5C,0x5D,0x5E,0x5F,0x60,0x61,0x62,0x63,0x64,0x65,
        0x66,0x67,0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,0x70,0x71,0x72,0x73,
        0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x7B,0x7C,0x7D,0x7E,0x7F,0x80,0x81,
        0x82,0x83,0x84,0x85,0x86,0x87,0x88,0x89,0x8A,0x8B,0x8C,0x8D,0x8E,0x8F,
        0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9A,0x9B,0x9C,0x9D,
        0x9E,0x9F,0xA0,0xA1,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7,0xA8,0xA9,0xAA,0xAB,
        0xAC,0xAD,0xAE,0xAF,0xB0,0xB1,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,
        0xBA,0xBB,0xBC,0xBD,0xBE,0xBF,0xC0,0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,
        0xC8,0xC9,0xCA,0xCB,0xCC,0xCD,0xCE,0xCF,0xD0,0xD1,0xD2,0xD3,0xD4,0xD5,
        0xD6,0xD7,0xD8,0xD9,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,0xE0,0xE1,0xE2,0xE3,
        0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xEB,0xEC,0xED,0xEE,0xEF,0xF0,0xF1,
        0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,0xF9,0xFA,0xFB,0xFC,0xFD,0xFE,0xFF
    };

    String path = sig->path;
    f32 point_size = sig->point_size;
    AC_Asset *asset = sig->asset;

    P_LogInfoF("Loading font \"%F\" (point size %F)", FmtString(path), FmtFloat((f64)point_size));
    i64 start_ns = TimeNs();

    Assert(StringEndsWith(path, Lit(".ttf")));
    Assert(countof(font_codes) < F_LookupTableSize);

    /* Decode */
    RES_Resource res = RES_OpenResource(path);
    if (!RES_ResourceExists(&res))
    {
        /* FIME: Load baked font instead of panicking */
        Panic(StringFormat(scratch.arena,
                             Lit("Font \"%F\" not found"),
                             FmtString(path)));
    }
    TTF_Result result = TTF_Decode(scratch.arena, RES_GetResourceData(&res), point_size, font_codes, countof(font_codes));
    RES_CloseResource(&res);

    /* Send texture to GPU */
    GPU_Resource *texture = GPU_AcquireTexture(GP_TEXTURE_FORMAT_R8G8B8A8_UNORM, 0, VEC2I32(result.image_width, result.image_height), result.image_pixels);

    /* Acquire store memory */
    F_Font *font = 0;
    {
        AC_Store store = AC_OpenStore();
        font = PushStruct(store.arena, F_Font);
        font->glyphs = PushStructsNoZero(store.arena, F_Glyph, result.glyphs_count);
        font->lookup = PushStructs(store.arena, u16, F_LookupTableSize);
        AC_CloseStore(&store);
    }

    /* Set font data */
    font->texture = texture;
    font->image_width = result.image_width;
    font->image_height = result.image_height;
    font->glyphs_count = result.glyphs_count;
    font->point_size = point_size;

    /* FIXME: Load baked font instead of panicking */
    if (font->glyphs_count <= 0)
    {
        Panic(StringFormat(scratch.arena,
                             Lit("Parsed 0 glyphs from font \"%F\"!"),
                             FmtString(path)));
    }

    /* Copy glyphs from decode result */
    StaticAssert(sizeof(*font->glyphs) == sizeof(*result.glyphs));  /* Font glyph size must match TTF glyph size for memcpy */
    CopyBytes(font->glyphs, result.glyphs, sizeof(*font->glyphs) * result.glyphs_count);

    /* Build lookup table */
    for (u64 i = 0; i < countof(font_codes); ++i)
    {
        u32 codepoint = font_codes[i];
        font->lookup[codepoint] = result.cache_indices[i];
    }

    P_LogSuccessF("Loaded font \"%F\" (point size %F) in %F seconds", FmtString(path), FmtFloat((f64)point_size), FmtFloat(SecondsFromNs(TimeNs() - start_ns)));
    AC_MarkReady(asset, font);

    EndScratch(scratch);
}

////////////////////////////////
//~ Load

/* Returns the asset from the asset cache */
AC_Asset *F_LoadAsset(String path, f32 point_size, b32 wait)
{
    __prof;
    TempArena scratch = BeginScratchNoConflict();

    /* Concatenate point_size to path for key */
    String key = StringFormat(scratch.arena,
                              Lit("%F%F_font"),
                              FmtString(path),
                              FmtFloatP((f64)point_size, 1));
    u64 hash = AC_HashFromKey(key);
    b32 is_first_touch;
    AC_Asset *asset = AC_TouchCache(key, hash, &is_first_touch);

    if (is_first_touch)
    {
        AC_MarkLoading(asset);
        F_LoadJob_Desc *desc = PushJobDesc(F_LoadJob, .pool = JobPool_Background, .priority = JobPriority_Low);
        desc->sig->asset = asset;
        desc->sig->path = PushString(desc->arena, path);
        desc->sig->point_size = point_size;
        RunJobEx((GenericJobDesc *)desc);
        if (wait)
        {
            AC_YieldOnAssetReady(asset);
        }
    }

    EndScratch(scratch);
    return asset;
}

F_Font *F_LoadFontAsync(String path, f32 point_size)
{
    __prof;
    AC_Asset *asset = F_LoadAsset(path, point_size, 0);
    F_Font *f = (F_Font *)AC_DataFromStore(asset);
    return f;
}

F_Font *F_LoadFontWait(String path, f32 point_size)
{
    __prof;
    AC_Asset *asset = F_LoadAsset(path, point_size, 1);
    AC_YieldOnAssetReady(asset);
    F_Font *f = (F_Font *)AC_DataFromStore(asset);
    return f;
}

////////////////////////////////
//~ Get glyph

F_Glyph *F_GetGlyph(F_Font *font, u32 codepoint)
{
    if (codepoint < F_LookupTableSize)
    {
        u16 index = font->lookup[codepoint];
        if (index < font->glyphs_count)
        {
            return &font->glyphs[index];
        }
    }
    if (codepoint == '?')
    {
        return &font->glyphs[font->lookup[0]];
    }
    else
    {
        return &font->glyphs[font->lookup['?']];
    }
}