ffi go

.gitignore

@@ -10,6 +10,8 @@ Cargo.lock
 # These are backup files generated by rustfmt
 **/*.rs.bk
 
+main_static
+
 .DS_Store
 log
 NOTES

Cargo.toml

@@ -10,7 +10,7 @@ edition = "2021"
 [lib]
 name = "gameboy"
 path = "src/lib.rs"
-crate-type = ["cdylib", "rlib"]
+crate-type = ["cdylib", "rlib", "staticlib"]
 
 [profile.release]
 opt-level = "s"

Makefile

@@ -42,3 +42,11 @@ web-publish:
 web-build:
 	cd web && npm run build
 
+# cargo install cbindgen
+ffi-build:
+	cargo build --release
+	cbindgen . -o gameboy.h --lang c
+
+ffi:
+	cp target/release/libgameboy.a examples/ffi-go/
+	cd examples/ffi-go && go build main_static.go

examples/ffi-go/main_static.go

@@ -0,0 +1,22 @@
+package main
+
+// NOTE: There should be NO space between the comments and the `import "C"` line.
+// The -ldl is sometimes necessary to fix linker errors about `dlsym`.
+
+/*
+#cgo LDFLAGS: ./libgameboy.a -ldl
+#include "../../gameboy.h"
+#include <stdlib.h>
+*/
+import "C"
+// import "unsafe"
+
+func main() {
+	// str1 := C.CString("world")
+	// str2 := C.CString("this is code from the static library")
+	// defer C.free(unsafe.Pointer(str1))
+	// defer C.free(unsafe.Pointer(str2))
+
+	// C.hello(str1)
+	// C.whisper(str2)
+}

gameboy.h

@@ -0,0 +1,43 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define CYCLES 70224
+
+#define HEIGHT 144
+
+#define WIDTH 160
+
+enum KeypadKey {
+  Right,
+  Left,
+  Up,
+  Down,
+  A,
+  B,
+  Select,
+  Start,
+};
+typedef uint8_t KeypadKey;
+
+typedef struct String String;
+
+typedef struct ImageBuffer {
+  int32_t len;
+  const uint8_t *data;
+} ImageBuffer;
+
+void load_rom(const unsigned char *bytes, uintptr_t bytes_length);
+
+void frame(void);
+
+void keydown(KeypadKey key);
+
+void keyup(KeypadKey key);
+
+struct ImageBuffer image(void);
+
+extern void log(struct String s);
+
+extern void log_u32(uint32_t a);

src/input.rs

@@ -6,7 +6,7 @@ pub struct Keypad {
 }
 
 #[derive(Copy, Clone)]
-#[repr(C)]
+#[repr(u8)]
 pub enum KeypadKey {
     Right,
     Left,

src/lib.rs

@@ -22,8 +22,7 @@ pub async fn start() {
     // TODO: Process GL
 }
 
-#[no_mangle]
-pub static GAMEBOY: OnceLock<Mutex<Option<crate::gameboy::Gameboy>>> = OnceLock::new();
+static GAMEBOY: OnceLock<Mutex<Option<crate::gameboy::Gameboy>>> = OnceLock::new();
 
 #[cfg(target_vendor = "apple")]
 unsafe impl Send for crate::gameboy::Gameboy {}
@@ -65,28 +64,6 @@ pub extern "C" fn keyup(key: KeypadKey) {
     }
 }
 
-#[no_mangle]
-pub extern "C" fn width() -> u32 {
-    if let Some(gb) = GAMEBOY.get() {
-        if let Ok(mut locked_gb) = gb.lock() {
-            return locked_gb.as_mut().unwrap().width;
-        }
-    }
-
-    0
-}
-
-#[no_mangle]
-pub extern "C" fn height() -> u32 {
-    if let Some(gb) = GAMEBOY.get() {
-        if let Ok(mut locked_gb) = gb.lock() {
-            return locked_gb.as_mut().unwrap().height;
-        }
-    }
-
-    0
-}
-
 #[repr(C)]
 pub struct ImageBuffer {
     len: i32,