From 5af19969ce48f0d7a06c9ac307a11413b95d3773 Mon Sep 17 00:00:00 2001
From: Jairinho <t4ngz3r0@gmail.com>
Date: Wed, 23 Feb 2022 19:39:14 -0300
Subject: [PATCH] playing with libretro

---
 Makefile             | 11 +++++----
 libretro/bridge.c    | 55 ++++++++++++++++++++++++++++++++++++++++++++
 libretro/libretro.go | 38 +++++++++++++++++++++---------
 3 files changed, 88 insertions(+), 16 deletions(-)
 create mode 100644 libretro/bridge.c

diff --git a/Makefile b/Makefile
index 4b6c98b..2c761a0 100644
--- a/Makefile
+++ b/Makefile
@@ -1,16 +1,17 @@
 TARGET=chip8_libretro
 LIBRETRO_CORE=$(TARGET).so
 LIBRETRO_HEADER=$(TARGET).h
+BUILD_VERSION=$(shell git rev-parse --short HEAD)
 
 # run: $(LIBRETRO_CORE)
 # 	retroarch -v -L $(LIBRETRO_CORE) roms/test_opcode.ch8
 
-$(LIBRETRO_CORE):
-	go build -buildmode=c-shared -o $@ ./libretro
-
-test:
-	go test -v -race ./chip8
+$(LIBRETRO_CORE): clean
+	go build -buildmode=c-shared -ldflags "-X 'main.BuildVersion=$(BUILD_VERSION)'" -o $@ ./libretro
 
 clean: 
 	rm -f $(LIBRETRO_CORE) $(LIBRETRO_HEADER)
 
+test:
+	go test -v -race ./chip8
+
diff --git a/libretro/bridge.c b/libretro/bridge.c
new file mode 100644
index 0000000..3c19524
--- /dev/null
+++ b/libretro/bridge.c
@@ -0,0 +1,55 @@
+#include <string.h>
+#include "libretro.h"
+
+// RETRO_API void retro_set_environment(retro_environment_t);
+// RETRO_API void retro_set_video_refresh(retro_video_refresh_t);
+// RETRO_API void retro_set_audio_sample(retro_audio_sample_t);
+// RETRO_API void retro_set_audio_sample_batch(retro_audio_sample_batch_t);
+// RETRO_API void retro_set_input_poll(retro_input_poll_t);
+// RETRO_API void retro_set_input_state(retro_input_state_t);
+
+RETRO_API void retro_init(void)
+{
+    void Initialize(void);
+    Initialize();
+}
+
+RETRO_API void retro_deinit(void)
+{
+    void Deinitialize(void);
+    Deinitialize();
+}
+
+RETRO_API unsigned retro_api_version(void)
+{
+    return 1;
+}
+
+RETRO_API void retro_get_system_info(struct retro_system_info *info)
+{
+    memset(info, 0, sizeof(*info));
+    void GetEmulatorInfo(struct retro_system_info * info);
+    GetEmulatorInfo(info);
+}
+
+RETRO_API void retro_get_system_av_info(struct retro_system_av_info *info)
+{
+    memset(info, 0, sizeof(*info));
+    void GetEmulatorAVInfo(struct retro_system_av_info * info);
+    GetEmulatorAVInfo(info);
+}
+
+// RETRO_API void retro_set_controller_port_device(unsigned port, unsigned device);
+// RETRO_API void retro_reset(void);
+// RETRO_API void retro_run(void);
+// RETRO_API size_t retro_serialize_size(void);
+// RETRO_API bool retro_serialize(void *data, size_t size);
+// RETRO_API bool retro_unserialize(const void *data, size_t size);
+// RETRO_API void retro_cheat_reset(void);
+// RETRO_API void retro_cheat_set(unsigned index, bool enabled, const char *code);
+// RETRO_API bool retro_load_game(const struct retro_game_info *game);
+// RETRO_API bool retro_load_game_special(unsigned game_type, const struct retro_game_info *info, size_t num_info);
+// RETRO_API void retro_unload_game(void);
+// RETRO_API unsigned retro_get_region(void);
+// RETRO_API void *retro_get_memory_data(unsigned id);
+// RETRO_API size_t retro_get_memory_size(unsigned id);
\ No newline at end of file
diff --git a/libretro/libretro.go b/libretro/libretro.go
index bf75183..0a03dee 100644
--- a/libretro/libretro.go
+++ b/libretro/libretro.go
@@ -9,24 +9,40 @@ typedef struct retro_system_av_info retro_system_av_info;
 */
 import "C"
 import (
-	"fmt"
+	"github.com/tangzero/chip8-emulator/chip8"
 )
 
-const RetroAPIVersion = 1
+var BuildVersion string
+var emulator *chip8.Emulator
 
-//export retro_init
-func retro_init() {
-	fmt.Println("loading chip8 core...")
+//export Initialize
+func Initialize() {
+	emulator = chip8.NewEmulator()
 }
 
-//export retro_deinit
-func retro_deinit() {
-	fmt.Println("unloading chip8 core...")
+//export Deinitialize
+func Deinitialize() {
+	emulator = nil
 }
 
-//export retro_api_version
-func retro_api_version() uint32 {
-	return RetroAPIVersion
+//export GetEmulatorInfo
+func GetEmulatorInfo(info *C.retro_system_info) {
+	info.library_name = C.CString("CHIP-8 Emulator by TangZero")
+	info.library_version = C.CString(BuildVersion)
+	info.valid_extensions = C.CString("ch8")
+	info.need_fullpath = false
+	info.block_extract = false
+}
+
+//export GetEmulatorAVInfo
+func GetEmulatorAVInfo(info *C.retro_system_av_info) {
+	info.geometry.base_width = 64
+	info.geometry.base_height = 32
+	info.geometry.max_width = 64
+	info.geometry.max_height = 32
+	info.geometry.aspect_ratio = 0.0
+	info.timing.fps = 60
+	info.timing.sample_rate = 44100
 }
 
 func main() {}