mach: wasm: initial implementation of Core, added js polyfill and

application html

src/mach.js

@@ -0,0 +1,77 @@
+const original_title = document.title;
+const text_decoder = new TextDecoder();
+const text_encoder = new TextEncoder();
+let log_buf = "";
+
+const mach = {
+  canvases: [],
+  wasm: undefined,
+  events: [],
+
+  init(wasm) {
+    this.wasm = wasm;
+  },
+
+  getString(str, len) {
+    const memory = mach.wasm.exports.memory.buffer;
+    return text_decoder.decode(new Uint8Array(memory, str, len));
+  },
+
+  setString(str, buf) {
+    const memory = this.wasm.exports.memory.buffer;
+    const strbuf = text_encoder.encode(str);
+    const outbuf = new Uint8Array(memory, buf, strbuf.length);
+    for (let i = 0; i < strbuf.length; i += 1) {
+        outbuf[i] = strbuf[i];
+    }
+  },
+
+  machCanvasInit(width, height, id) {
+    let canvas = document.createElement("canvas");
+    canvas.id = "#mach-canvas-" + mach.canvases.length;
+    canvas.width = width;
+    canvas.height = height;
+    canvas.tabIndex = 1;
+
+    mach.setString(canvas.id, id);
+
+    canvas.addEventListener("contextmenu", (ev) => ev.preventDefault());
+
+    document.body.appendChild(canvas);
+    return mach.canvases.push({ canvas: canvas, title: undefined }) - 1;
+  },
+
+  machCanvasDeinit(canvas) {
+    if (mach.canvases[canvas] != undefined) {
+      mach.canvases.splice(canvas, 1);
+    }
+  },
+
+  machCanvasSetTitle(canvas, title, len) {
+    const str = len > 0 ?
+      mach.getString(title, len) :
+      original_title;
+
+    mach.canvases[canvas].title = str;
+  },
+
+  machCanvasSetSize(canvas, width, height) {
+    const cv = mach.canvases[canvas];
+    if (width > 0 && height > 0) {
+      cv.canvas.width = width;
+      cv.canvas.height = height;
+    }
+  },
+
+  machCanvasGetWidth(canvas) {
+    const cv = mach.canvases[canvas];
+    return cv.canvas.width;
+  },
+
+  machCanvasGetHeight(canvas) {
+    const cv = mach.canvases[canvas];
+    return cv.canvas.height;
+  },
+};
+
+export { mach };

src/wasm.zig

@@ -4,17 +4,42 @@ const Engine = @import("Engine.zig");
 const structs = @import("structs.zig");
 const enums = @import("enums.zig");
 
-const js = struct {};
+const js = struct {
+    extern fn machCanvasInit(width: u32, height: u32, selector_id: *u8) CanvasId;
+    extern fn machCanvasDeinit(canvas: CanvasId) void;
+    extern fn machCanvasSetTitle(canvas: CanvasId, title: [*]const u8, len: u32) void;
+    extern fn machCanvasSetSize(canvas: CanvasId, width: u32, height: u32) void;
+    extern fn machCanvasGetWidth(canvas: CanvasId) u32;
+    extern fn machCanvasGetHeight(canvas: CanvasId) u32;
+};
+
+pub const CanvasId = u32;
 
 pub const CoreWasm = struct {
-    pub fn init(_: std.mem.Allocator, _: *Engine) !CoreWasm {
-        return CoreWasm{};
+    id: CanvasId,
+    selector_id: []const u8,
+
+    pub fn init(allocator: std.mem.Allocator, eng: *Engine) !CoreWasm {
+        const options = eng.options;
+        var selector = [1]u8{0} ** 15;
+        const id = js.machCanvasInit(options.width, options.height, &selector[0]);
+
+        const title = std.mem.span(options.title);
+        js.machCanvasSetTitle(id, title.ptr, title.len);
+
+        return CoreWasm{
+            .id = id,
+            .selector_id = try allocator.dupe(u8, selector[0 .. selector.len - @as(u32, if (selector[selector.len - 1] == 0) 1 else 0)]),
+        };
     }
 
     pub fn setShouldClose(_: *CoreWasm, _: bool) void {}
 
-    pub fn getFramebufferSize(_: *CoreWasm) !structs.Size {
-        return structs.Size{ .width = 0, .height = 0 };
+    pub fn getFramebufferSize(core: *CoreWasm) !structs.Size {
+        return structs.Size{
+            .width = js.machCanvasGetWidth(core.id),
+            .height = js.machCanvasGetHeight(core.id),
+        };
     }
 
     pub fn setSizeLimits(_: *CoreWasm, _: structs.SizeOptional, _: structs.SizeOptional) !void {}