chore: initial drawing window support

frontends/libretro/src/lib.rs

 #![allow(clippy::uninlined_format_args)]
 
-use std::os::raw::{c_char, c_uint};
+use std::os::raw::{c_char, c_float, c_uint, c_void};
+
+use boytacean::{
+    gb::GameBoy,
+    ppu::{DISPLAY_HEIGHT, DISPLAY_WIDTH},
+};
 
 const RETRO_API_VERSION: u32 = 1;
+const REGION_NTSC: u32 = 0;
+
+//const RETRO_MEMORY_SAVE_RAM: u32 = 0;
+//const RETRO_MEMORY_SYSTEM_RAM: u32 = 0;
+
+static mut ENVIRONMENT_CALLBACK: Option<extern "C" fn(u32, *const c_void) -> bool> = None;
+static mut VIDEO_REFRESH_CALLBACK: Option<extern "C" fn(*const u8)> = None;
+static mut AUDIO_SAMPLE_CALLBACK: Option<extern "C" fn(i16, i16)> = None;
+static mut AUDIO_SAMPLE_BATCH_CALLBACK: Option<extern "C" fn(*const i16, usize)> = None;
+static mut INPUT_POLL_CALLBACK: Option<extern "C" fn()> = None;
+static mut INPUT_STATE_CALLBACK: Option<
+    extern "C" fn(port: u32, device: u32, index: u32, id: u32) -> i16,
+> = None;
+
+#[repr(C)]
+pub struct RetroGameInfo {
+    pub path: *const c_char,
+    pub data: *const c_void,
+    pub size: usize,
+    pub meta: *const c_char,
+}
 
 #[repr(C)]
 pub struct RetroSystemInfo {
@@ -13,6 +39,27 @@ pub struct RetroSystemInfo {
     pub block_extract: bool,
 }
 
+#[repr(C)]
+pub struct RetroGameGeometry {
+    pub base_width: c_uint,
+    pub base_height: c_uint,
+    pub max_width: c_uint,
+    pub max_height: c_uint,
+    pub aspect_ratio: c_float,
+}
+
+#[repr(C)]
+pub struct RetroSystemAvInfo {
+    geometry: RetroGameGeometry,
+    timing: RetroSystemTiming,
+}
+
+#[repr(C)]
+pub struct RetroSystemTiming {
+    fps: f64,
+    sample_rate: f64,
+}
+
 #[no_mangle]
 pub extern "C" fn retro_init() {
     println!("retro_init()");
@@ -36,7 +83,7 @@ pub extern "C" fn retro_api_version() -> c_uint {
 
 #[no_mangle]
 pub extern "C" fn retro_get_system_info(info: *mut RetroSystemInfo) {
-    println!("retro_get_system_info");
+    println!("retro_get_system_info()");
     unsafe {
         (*info).library_name = "Boytacean\0".as_ptr() as *const c_char;
         (*info).library_version = "v0.9.6\0".as_ptr() as *const c_char;
@@ -47,13 +94,79 @@ pub extern "C" fn retro_get_system_info(info: *mut RetroSystemInfo) {
 }
 
 #[no_mangle]
-pub extern "C" fn retro_get_system_av_info() {
+pub extern "C" fn retro_get_system_av_info(info: *mut RetroSystemAvInfo) {
     println!("retro_get_system_av_info()");
+    unsafe {
+        (*info).geometry.base_width = DISPLAY_WIDTH as u32;
+        (*info).geometry.base_height = DISPLAY_HEIGHT as u32;
+        (*info).geometry.max_width = DISPLAY_WIDTH as u32 * 32;
+        (*info).geometry.max_height = DISPLAY_HEIGHT as u32 * 32;
+        (*info).geometry.aspect_ratio = DISPLAY_WIDTH as f32 / DISPLAY_HEIGHT as f32;
+        (*info).timing.fps = GameBoy::VISUAL_FREQ as f64;
+        (*info).timing.sample_rate = 44100.0;
+    }
 }
 
 #[no_mangle]
-pub extern "C" fn retro_set_environment() {
+pub extern "C" fn retro_set_environment(
+    callback: Option<extern "C" fn(u32, *const c_void) -> bool>,
+) {
     println!("retro_set_environment()");
+    unsafe {
+        ENVIRONMENT_CALLBACK = callback;
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn retro_set_video_refresh(callback: Option<extern "C" fn(*const u8)>) {
+    println!("retro_set_video_refresh()");
+    unsafe {
+        VIDEO_REFRESH_CALLBACK = callback;
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn retro_set_audio_sample(callback: Option<extern "C" fn(i16, i16)>) {
+    println!("retro_set_audio_sample()");
+    unsafe {
+        AUDIO_SAMPLE_CALLBACK = callback;
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn retro_set_audio_sample_batch(callback: Option<extern "C" fn(*const i16, usize)>) {
+    println!("retro_set_audio_sample_batch()");
+    unsafe {
+        AUDIO_SAMPLE_BATCH_CALLBACK = callback;
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn retro_set_input_poll(callback: Option<extern "C" fn()>) {
+    println!("retro_set_input_poll()");
+    unsafe {
+        INPUT_POLL_CALLBACK = callback;
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn retro_set_input_state(
+    callback: Option<extern "C" fn(port: u32, device: u32, index: u32, id: u32) -> i16>,
+) {
+    println!("retro_set_input_state()");
+    unsafe {
+        INPUT_STATE_CALLBACK = callback;
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn retro_load_game_special(
+    _system: u32,
+    _info: *const RetroGameInfo,
+    _num_info: usize,
+) -> bool {
+    println!("retro_load_game_special()");
+    false
 }
 
 #[no_mangle]
@@ -67,8 +180,15 @@ pub extern "C" fn retro_run() {
 }
 
 #[no_mangle]
-pub extern "C" fn retro_load_game() {
+pub extern "C" fn retro_get_region() -> u32 {
+    println!("retro_get_region()");
+    REGION_NTSC
+}
+
+#[no_mangle]
+pub extern "C" fn retro_load_game(_game: *const RetroGameInfo) -> bool {
     println!("retro_load_game()");
+    return true;
 }
 
 #[no_mangle]
@@ -77,13 +197,23 @@ pub extern "C" fn retro_unload_game() {
 }
 
 #[no_mangle]
-pub extern "C" fn retro_get_memory_data() {
+pub extern "C" fn retro_get_memory_data(memory_id: u32) -> *mut c_void {
     println!("retro_get_memory_data()");
+    match memory_id {
+        //RETRO_MEMORY_SAVE_RAM => SAVE_RAM.as_mut_ptr() as *mut c_void,
+        //RETRO_MEMORY_SYSTEM_RAM => SYSTEM_RAM.as_mut_ptr() as *mut c_void,
+        _ => std::ptr::null_mut(),
+    }
 }
 
 #[no_mangle]
-pub extern "C" fn retro_get_memory_size() {
+pub extern "C" fn retro_get_memory_size(memory_id: u32) -> usize {
     println!("retro_get_memory_size()");
+    match memory_id {
+        //RETRO_MEMORY_SAVE_RAM => 0,
+        //RETRO_MEMORY_SYSTEM_RAM => 0,
+        _ => 0,
+    }
 }
 
 #[no_mangle]