Got a basic image drawing program working

1 year ago · 881dd4a55e
7 changed files with 119 additions and 0 deletions
--- a/.cargo/config
+++ b/.cargo/config
@ -0,0 +1,4 @@
+
+[build]
+target = "wasm32-unknown-unknown"
+
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1,2 @@
+/target
+Cargo.lock
--- a/Cargo.toml
+++ b/Cargo.toml
@ -0,0 +1,14 @@
+[package]
+name = "wt"
+version = "0.1.0"
+authors = ["thajohns <thajohns@clarkson.edu>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+wee_alloc = "0.4.5"
+#wasm-bindgen = "0.2.59"
+
+[lib]
+crate-type = ["cdylib"]
--- a/index.html
+++ b/index.html
@ -0,0 +1,8 @@
+<html>
+  <head>
+    <script defer src="index.js"></script>
+  </head>
+  <body id="body">
+    <canvas id="canvas" height=1000 width=1500></canvas>
+  </body>
+</html>
--- a/index.js
+++ b/index.js
@ -0,0 +1,38 @@
+canvas = document.getElementById("canvas");
+ctx = canvas.getContext("2d");
+
+function get_string(memory, pointer, size)
+{
+  var array = new Int8Array(memory.buffer, pointer, size);
+  return (new TextDecoder()).decode(array);
+}
+
+function paint(memory, pointer, width, height)
+{
+  array = new Uint8ClampedArray(memory.buffer, pointer, 4 * width * height);
+  data = new ImageData(array, width, height);
+  ctx.putImageData(data, 0, 0);
+}
+
+fetch("wt.wasm").then(response => response.arrayBuffer()).then(bytes =>
+  {
+    var memory;
+    WebAssembly.instantiate(bytes, { env:
+      {
+        console_log: function(str, len)
+        {
+          console.log(get_string(memory, str, len));
+        },
+        extern_paint: function(pointer, width, height)
+        {
+          paint(memory, pointer, width, height);
+        }
+      } }).then(mod =>
+      {
+        memory = mod.instance.exports.memory;
+        mod.instance.exports.entrypoint();
+        mod.instance.exports.paint_red(canvas.width, canvas.height);
+      }
+    )
+  });
+
--- a/src/lib.rs
+++ b/src/lib.rs
@ -0,0 +1,52 @@
+
+extern crate wee_alloc;
+
+use core::mem::transmute;
+
+#[global_allocator]
+pub static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
+
+extern "C"
+{
+  #[no_mangle]
+  fn console_log(_: *const u8, _: usize);
+  #[no_mangle]
+  fn extern_paint(ptr: *const u8, w: usize, h: usize);
+}
+
+fn log(string: &str)
+{
+  unsafe
+  {
+    let (ptr, size) = transmute::<_, (*const u8, usize)>(string);
+    console_log(ptr, size);
+  }
+}
+
+fn paint(buffer: &[u8], w: usize, h: usize)
+{
+  unsafe { extern_paint(buffer.as_ptr(), w, h); }
+}
+
+#[no_mangle]
+pub extern "C" fn entrypoint()
+{
+  log("Test from Rust");
+}
+
+#[no_mangle]
+pub extern "C" fn paint_red(w: usize, h: usize)
+{
+  let mut buffer = vec![0; 4 * w * h];
+  let mut c: (u8, u8, u8) = (0, 0, 0);
+  for ii in 0 .. w * h
+  {
+    buffer[4 * ii] = c.0;
+    buffer[4 * ii + 1] = c.1;
+    buffer[4 * ii + 2] = c.2;
+    buffer[4 * ii + 3] = 255;
+    c = (c.0.wrapping_add(1), c.1.wrapping_add(254), c.2.wrapping_add(2));
+  }
+  paint(&buffer, w, h);
+}
+
--- a/wt.wasm
+++ b/wt.wasm
@ -0,0 +1 @@
+/home/primary/rust/dabble/webasm/target/wasm32-unknown-unknown/debug/wt.wasm