mach: comptime interface-like implementation of engine cores

src/Engine.zig

@@ -45,6 +45,8 @@ pub const Options = struct {
     power_preference: gpu.PowerPreference = .none,
 };
 
+const Engine = @This();
+
 /// Window, events, inputs etc.
 core: Core,
 
@@ -53,6 +55,8 @@ gpu_driver: GpuDriver,
 
 allocator: Allocator,
 
+options: Options,
+
 /// The amount of time (in seconds) that has passed since the last frame was rendered.
 ///
 /// For example, if you are animating a cube which should rotate 360 degrees every second,
@@ -63,19 +67,41 @@ delta_time_ns: u64 = 0,
 timer: std.time.Timer,
 
 pub const Core = struct {
-    internal: union {
-        window: glfw.Window,
-    },
+    internal: GetCoreInternalType(),
 };
 
 pub const GpuDriver = struct {
+    internal: GetGpuDriverInternalType(),
+
     device: gpu.Device,
     backend_type: gpu.Adapter.BackendType,
     swap_chain: ?gpu.SwapChain,
     swap_chain_format: gpu.Texture.Format,
 
-    native_instance: gpu.NativeInstance,
     surface: ?gpu.Surface,
     current_desc: gpu.SwapChain.Descriptor,
     target_desc: gpu.SwapChain.Descriptor,
 };
+
+pub fn init(allocator: std.mem.Allocator, options: Options) !Engine {
+    var engine = Engine{
+        .allocator = allocator,
+        .options = options,
+        .timer = try std.time.Timer.start(),
+        .core = undefined,
+        .gpu_driver = undefined,
+    };
+
+    engine.core.internal = try GetCoreInternalType().init(allocator, &engine);
+    engine.gpu_driver.internal = try GetGpuDriverInternalType().init(allocator, &engine);
+
+    return engine;
+}
+
+fn GetCoreInternalType() type {
+    return @import("native.zig").CoreGlfw;
+}
+
+fn GetGpuDriverInternalType() type {
+    return @import("native.zig").GpuDriverNative;
+}