From 6a759884893f984776e0aa5d6deba2ac2e9797da Mon Sep 17 00:00:00 2001
From: Dennis Ranke <dennis.ranke@gmail.com>
Date: Sat, 1 Jan 2022 15:51:18 +0100
Subject: [PATCH] update rust example

---
 examples/rust/readme.txt |   8 ++++----
 examples/rust/tunnel.rs  |  14 +++++++++++---
 examples/rust/tunnel.uw8 | Bin 137 -> 119 bytes
 3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/examples/rust/readme.txt b/examples/rust/readme.txt
index 450e4dd..b21a897 100644
--- a/examples/rust/readme.txt
+++ b/examples/rust/readme.txt
@@ -5,8 +5,8 @@ A nightly rust compiler is needed for the unstable sqrtf32
 intrinsic.
 
 Simply compiling with rustc as shown in build.sh results in a
-342 byte tunnel.wasm. Using wasm-opt this can be reduced to
-243 bytes.
+371 byte tunnel.wasm. Using wasm-opt this can be reduced to
+260 bytes.
 
 When you disassemble this wasm file using wasm2wat you can see
 these globals and exports:
@@ -21,5 +21,5 @@ values that are not simple scalars (i32, f32, etc.). Since our
 code doesn't actually use any of that, we can just delete them
 in a text editor and assemble the code again with wat2wasm.
 
-This gives us a 199 byte wasm file. Running this through
-uw8-tool pack brings us to the final size of 137 bytes.
\ No newline at end of file
+This gives us a 216 byte wasm file. Running this through
+uw8 pack brings us to the final size of 119 bytes.
\ No newline at end of file
diff --git a/examples/rust/tunnel.rs b/examples/rust/tunnel.rs
index 5a7dc5d..83527fe 100644
--- a/examples/rust/tunnel.rs
+++ b/examples/rust/tunnel.rs
@@ -9,12 +9,20 @@ mod env {
     extern "C" {
         pub fn atan2(x: f32, y: f32) -> f32;
     }
+
+    extern "C" {
+        pub fn time() -> f32;
+    }
 }
 
 fn atan2(x: f32, y: f32) -> f32 {
     unsafe { env::atan2(x, y) }
 }
 
+fn time() -> f32 {
+    unsafe { env::time() }
+}
+
 fn sqrt(v: f32) -> f32 {
     unsafe { core::intrinsics::sqrtf32(v) }
 }
@@ -29,14 +37,14 @@ fn ftoi(v: f32) -> i32 {
 }
 
 #[no_mangle]
-pub fn tic(time: i32) {
+pub fn upd() {
     for i in 0..320 * 240 {
-        let t = time as f32 / 10 as f32;
+        let t = time() * 63 as f32;
         let x = (i % 320 - 160) as f32;
         let y = (i / 320 - 120) as f32;
         let d = 40000 as f32 / sqrt(x * x + y * y + 1 as f32);
         let u = atan2(x, y) * 512f32 / 3.141;
-        let c = (ftoi(d + t * 2 as f32) ^ ftoi(u + t)) as u8;
+        let c = (ftoi(d + t * 2 as f32) ^ ftoi(u + t)) as u8 >> 4;
         unsafe {
             *((120 + i) as *mut u8) = c;
         }
diff --git a/examples/rust/tunnel.uw8 b/examples/rust/tunnel.uw8
index 21c1c16a12e9549578ec6e0f2706482ff6b8f994..50c01f3f3435ee5b6c8f43743f679c17cd100ffc 100644
GIT binary patch
literal 119
zcmV--0Eqtr1#ia}{*%7ra>hbgU8bpqy|#X0LF+0s*nH{b>t`VtLE{d)%$6?ECNRU!
z^qaUOzNvK8)5AEzspQZ3njgWf=E#z09qo+t%?E+p%iI)|LBjg6m~*6PThd6Sn6$<x
ZY*wac<Sy$Ac<XdQT2s8M(xv@f<r#ctLk|D|

literal 137
zcmZSNYGq_>Vq{{jWvo|V*yPN>px`)Fk<pPsk%8Gkfx)q%fz_P_#Q4FGrN9WJAJhSf
z159~JEI=|RJ8P2?lLCul17r3kC1wFOpne9IDbA{Fo(@wdtx#ZeW^kC}rog1YG(~|~
ffqBX#pnQY<q=`VeVk@9k433OhiVQrA+}zv%AZ#A=