add frame counter at memory location 72

examples/curlywas/tunnel.cwa

@@ -3,12 +3,14 @@ include "../include/microw8-api.cwa"
 export fn upd() {
     let i: i32;
     loop pixels {
-        let inline t = time() * 63 as f32;
-        let lazy x = (i % 320 - 160) as f32;
-        let lazy y = (i / 320 - 120) as f32;
-        let inline d = 40000 as f32 / sqrt(x * x + y * y);
-        let inline u = atan2(x, y) * (512.0 / 3.141);
-        let inline c = ((i32.trunc_sat_f32_s(d + t * 2 as f32) ^ i32.trunc_sat_f32_s(u + t)) & 255) >> 4;
+        let inline t = 16!56;
+        let inline x = (i % 320 - 160) as f32;
+        let inline y = (i #/ 320 - 120) as f32;
+        let inline d = 0xa000 as f32 / sqrt(x * x + y * y);
+        let inline a = atan2(x, y) * 163_f; // (512 / pi)
+        let inline u = i32.trunc_sat_f32_s(a) + t;
+        let inline v = i32.trunc_sat_f32_s(d) + t * 2;
+        let inline c = ((v ^ u) #/ 16) % 16;
         i?FRAMEBUFFER = c;
 
         branch_if (i := i + 1) < 320*240: pixels;

site/content/docs.md

@@ -21,7 +21,7 @@ loaded.
 00000-00040: user memory
 00040-00044: time since module start in ms
 00044-0004c: gamepad state
-0004c-00050: reserved
+0004c-00050: number of frames since module start
 00050-00070: sound data (synced to sound thread)
 00070-00078: reserved
 00078-12c78: frame buffer

src/run_native.rs

@@ -27,6 +27,7 @@ struct UW8Instance {
     end_frame: TypedFunc<(), ()>,
     update: Option<TypedFunc<(), ()>>,
     start_time: Instant,
+    frame_counter: u32,
     watchdog: Arc<Mutex<UW8WatchDog>>,
     sound_tx: Option<mpsc::SyncSender<RegisterUpdate>>,
 }
@@ -159,6 +160,7 @@ impl super::Runtime for MicroW8 {
             end_frame,
             update,
             start_time: Instant::now(),
+            frame_counter: 0,
             watchdog,
             sound_tx,
         });
@@ -191,8 +193,11 @@ impl super::Runtime for MicroW8 {
                 let mem = instance.memory.data_mut(&mut instance.store);
                 mem[64..68].copy_from_slice(&time.to_le_bytes());
                 mem[68..72].copy_from_slice(&input.gamepads);
+                mem[72..76].copy_from_slice(&instance.frame_counter.to_le_bytes());
             }
 
+            instance.frame_counter = instance.frame_counter.wrapping_add(1);
+
             instance.store.set_epoch_deadline(self.timeout as u64);
             if let Some(ref update) = instance.update {
                 if let Err(err) = update.call(&mut instance.store, ()) {

web/src/microw8.js

@@ -240,6 +240,7 @@ export default function MicroW8(screen, config = {}) {
             await audioReadyPromise;
     
             let startTime = Date.now();
+            let frameCounter = 0;
     
             const timePerFrame = 1000 / 60;
 
@@ -306,6 +307,7 @@ export default function MicroW8(screen, config = {}) {
                         let time = Date.now() - startTime;
                         u32Mem[16] = time;
                         u32Mem[17] = pad | gamepad;
+                        u32Mem[18] = frameCounter++;
                         if(instance.exports.upd) {
                             instance.exports.upd();
                         }