mach: wasm: Add initial framework bones

src/Engine.zig

@@ -1,5 +1,6 @@
 const std = @import("std");
 const Allocator = std.mem.Allocator;
+const builtin = @import("builtin");
 const glfw = @import("glfw");
 const gpu = @import("gpu");
 const structs = @import("structs.zig");
@@ -88,9 +89,11 @@ pub fn init(allocator: std.mem.Allocator, options: structs.Options) !Engine {
 }
 
 fn GetCoreInternalType() type {
+    if (builtin.cpu.arch == .wasm32) return @import("wasm.zig").CoreWasm;
     return @import("native.zig").CoreGlfw;
 }
 
 fn GetGpuDriverInternalType() type {
+    if (builtin.cpu.arch == .wasm32) return @import("wasm.zig").GpuDriverWeb;
     return @import("native.zig").GpuDriverNative;
 }

src/Timer.zig

@@ -6,7 +6,29 @@ const Timer = @This();
 backing_timer: BackingTimerType = undefined,
 
 // TODO: verify declarations and its signatures
-const BackingTimerType = if (builtin.cpu.arch == .wasm32) void else std.time.Timer;
+const BackingTimerType = if (builtin.cpu.arch == .wasm32) struct {
+    pad0: u8 = 0,
+
+    const WasmTimer = @This();
+
+    fn start() !WasmTimer {
+        return WasmTimer{};
+    }
+
+    fn read(_: *WasmTimer) u64 {
+        return 0;
+    }
+
+    fn reset(_: *WasmTimer) void {}
+
+    fn lap(_: *WasmTimer) u64 {
+        return 0;
+    }
+
+    fn timeToNs(_: f64) u64 {
+        return 0;
+    }
+} else std.time.Timer;
 
 /// Initialize the timer.
 pub fn start() !Timer {

src/wasm.zig

@@ -0,0 +1,52 @@
+const std = @import("std");
+const App = @import("app");
+const Engine = @import("Engine.zig");
+const structs = @import("structs.zig");
+const enums = @import("enums.zig");
+
+const js = struct {};
+
+pub const CoreWasm = struct {
+    pub fn init(_: std.mem.Allocator, _: *Engine) !CoreWasm {
+        return CoreWasm{};
+    }
+
+    pub fn setShouldClose(_: *CoreWasm, _: bool) void {}
+
+    pub fn getFramebufferSize(_: *CoreWasm) !structs.Size {
+        return structs.Size{ .width = 0, .height = 0 };
+    }
+
+    pub fn setSizeLimits(_: *CoreWasm, _: structs.SizeOptional, _: structs.SizeOptional) !void {}
+
+    pub fn pollEvent(_: *CoreWasm) ?structs.Event {
+        return null;
+    }
+};
+
+pub const GpuDriverWeb = struct {
+    pub fn init(_: std.mem.Allocator, _: *Engine) !GpuDriverWeb {
+        return GpuDriverWeb{};
+    }
+};
+
+var app: App = undefined;
+var engine: Engine = undefined;
+
+export fn wasmInit() void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    const allocator = gpa.allocator();
+
+    const options = if (@hasDecl(App, "options")) App.options else structs.Options{};
+    engine = Engine.init(allocator, options) catch unreachable;
+
+    app.init(&engine) catch {};
+}
+
+export fn wasmUpdate() bool {
+    return app.update(&engine) catch false;
+}
+
+export fn wasmDeinit() void {
+    app.deinit(&engine);
+}