Use custom fonts ini nuklear when used via sokol

sokol_nuklear_use.c

// General nuklear info
// check https://github.com/Immediate-Mode-UI/Nuklear/blob/master/nuklear.h
// row 3950 and therabouts

// 1. Setup/init
snk_setup(&(snk_desc_t){
    .dpi_scale = sapp_dpi_scale(),
    .logger.func = slog_func,
});

// Initialize the font atlas
struct nk_font_atlas atlas;
nk_font_atlas_init_default(&atlas);
nk_font_atlas_begin(&atlas);

float scale = sapp_dpi_scale();  // For DPI scaling, needed for proper hidpi
struct nk_font* font_regular = nk_font_atlas_add_from_file(&atlas, "data/fonts/DroidSans.ttf", 8 * scale, 0);
if (!font_regular) {
    fprintf(stderr, "Failed to load font from file.\n");
    exit(EXIT_FAILURE);
}
struct nk_font* font_mono = nk_font_atlas_add_from_file(&atlas, "data/fonts/SourceCodePro-Regular.ttf", 8 * scale, 0);
if (!font_mono) {
    fprintf(stderr, "Failed to load font from file.\n");
    exit(EXIT_FAILURE);
}

// Bake to texture
int font_width, font_height;
const void* font_image = nk_font_atlas_bake(&atlas, &font_width, &font_height, NK_FONT_ATLAS_RGBA32);
if (!font_image) {
    fprintf(stderr, "Failed to bake font atlas.\n");
    exit(EXIT_FAILURE);
}

// Create the font texture 
sg_image font_sg_image = sg_make_image(&(sg_image_desc){
    .width = font_width,
    .height = font_height,
    .pixel_format = SG_PIXELFORMAT_RGBA8,
    .data.subimage[0][0] = {
        .ptr = font_image,
        .size = (size_t)(font_width * font_height) * sizeof(uint32_t)
    },
    .label = "custom-font-image"
});

// Create a sampler 
sg_sampler font_sg_smp = sg_make_sampler(&(sg_sampler_desc){
    .min_filter = SG_FILTER_LINEAR,
    .mag_filter = SG_FILTER_LINEAR,
    .wrap_u = SG_WRAP_CLAMP_TO_EDGE,
    .wrap_v = SG_WRAP_CLAMP_TO_EDGE,
    .label = "custom-font-sampler",
});

// Keep in mem
app_state.font_regular = font_regular;
app_state.font_mono = font_mono;

// Check if the texture atlas sampler was created successfully
if (font_sg_smp.id == SG_INVALID_ID) {
    fprintf(stderr, "Failed to create font sampler.\n");
    exit(EXIT_FAILURE);
}

// Check if the texture atlas image was created successfully
if (font_sg_image.id == SG_INVALID_ID) {
    fprintf(stderr, "Failed to create font texture.\n");
    exit(EXIT_FAILURE);
}

// Make a image + sample pair to use as font object and keep
app_state.font_tex = snk_make_image(&(snk_image_desc_t){
    .image = font_sg_image,
    .sampler = font_sg_smp,
});

// End  atlas creation and free data, we have a texture now that we use instead
nk_font_atlas_end(&atlas, snk_nkhandle(app_state.font_tex), NULL);


// Clean up the font atlas since we will not add more fonts
nk_font_atlas_cleanup(&atlas);