From bc4421b7541b895e273634beeb3bd0c8196101f3 Mon Sep 17 00:00:00 2001
From: David Allemang <allemang.d@gmail.com>
Date: Fri, 28 Jun 2024 21:43:30 -0400
Subject: [PATCH] extract generic au.Flights

---
 src/au.zig         |  1 +
 src/au/flights.zig | 57 ++++++++++++++++++++++++++++++++++++++++++++++
 src/main.zig       | 33 ++++-----------------------
 3 files changed, 63 insertions(+), 28 deletions(-)
 create mode 100644 src/au/flights.zig

diff --git a/src/au.zig b/src/au.zig
index 4cf299f..11a1815 100644
--- a/src/au.zig
+++ b/src/au.zig
@@ -6,6 +6,7 @@ const c = @import("c.zig");
 
 pub const Bus = @import("au/Bus.zig");
 pub const SwapChain = @import("au/SwapChain.zig");
+pub const Flights = @import("au/flights.zig").Flights;
 
 pub const use_debug_messenger = switch (builtin.mode) {
     .Debug, .ReleaseSafe => true,
diff --git a/src/au/flights.zig b/src/au/flights.zig
new file mode 100644
index 0000000..65350a9
--- /dev/null
+++ b/src/au/flights.zig
@@ -0,0 +1,57 @@
+const std = @import("std");
+const vk = @import("vk");
+const au = @import("../au.zig");
+
+pub fn Flights(T: type) type {
+    return struct {
+        const Self = @This();
+
+        const Flight = struct {
+            acquire: vk.Semaphore = .null_handle,
+            complete: vk.Semaphore = .null_handle,
+            fence: vk.Fence = .null_handle,
+            pool: vk.CommandPool = .null_handle,
+            ctx: T,
+        };
+
+        alloc: std.mem.Allocator,
+        flights: []Flight,
+        idx: usize,
+
+        pub fn init(alloc: std.mem.Allocator, n: usize) !Self {
+            var self: Self = .{
+                .alloc = alloc,
+                .flights = try alloc.alloc(Flight, n),
+                .idx = 0,
+            };
+            errdefer self.deinit();
+
+            for (self.flights) |*flight| {
+                flight.acquire = try au.D.createSemaphore(&.{}, null);
+                flight.complete = try au.D.createSemaphore(&.{}, null);
+                flight.fence = try au.D.createFence(&.{ .flags = .{ .signaled_bit = true } }, null);
+                flight.pool = try au.D.createCommandPool(&.{ .queue_family_index = au.device_config.family }, null);
+                flight.ctx = try T.init();
+            }
+
+            return self;
+        }
+
+        pub fn deinit(self: Self) void {
+            for (self.flights) |flight| {
+                au.D.destroySemaphore(flight.acquire, null);
+                au.D.destroySemaphore(flight.complete, null);
+                au.D.destroyFence(flight.fence, null);
+                au.D.destroyCommandPool(flight.pool, null);
+                flight.ctx.deinit();
+            }
+            self.alloc.free(self.flights);
+        }
+
+        pub fn next(self: *Self) Flight {
+            const idx = self.idx;
+            self.idx = (self.idx + 1) % self.flights.len;
+            return self.flights[idx];
+        }
+    };
+}
diff --git a/src/main.zig b/src/main.zig
index a45bc89..a1169d5 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -50,13 +50,6 @@ const vertices = [_]Vertex{
 
 const indices = [_]Index{ 4, 5, 6, 6, 5, 7 };
 
-const Flight = struct {
-    acquire: vk.Semaphore = .null_handle,
-    complete: vk.Semaphore = .null_handle,
-    fence: vk.Fence = .null_handle,
-    pool: vk.CommandPool = .null_handle,
-    frame: Frame,
-};
 
 const Frame = struct {
     pub fn init() !Frame {
@@ -181,27 +174,11 @@ pub fn main() !void {
     var sc = try au.SwapChain.init(alloc);
     defer sc.deinit();
 
-    const flights = try alloc.alloc(Flight, 3); // FRAMES IN FLIGHT
-    defer alloc.free(flights);
+    var flights = try au.Flights(Frame).init(alloc, 3); // FRAMES IN FLIGHT
+    defer flights.deinit();
 
-    for (flights) |*flight| {
-        flight.acquire = try au.D.createSemaphore(&.{}, null);
-        flight.complete = try au.D.createSemaphore(&.{}, null);
-        flight.fence = try au.D.createFence(&.{ .flags = .{ .signaled_bit = true } }, null);
-        flight.pool = try au.D.createCommandPool(&.{ .queue_family_index = au.device_config.family }, null);
-        flight.frame = try Frame.init();
-    }
-    defer for (flights) |flight| {
-        au.D.destroySemaphore(flight.acquire, null);
-        au.D.destroySemaphore(flight.complete, null);
-        au.D.destroyFence(flight.fence, null);
-        au.D.destroyCommandPool(flight.pool, null);
-        flight.frame.deinit();
-    };
-
-    var flight_idx: usize = 0;
-    while (!au.W.should_close()) : (flight_idx = (flight_idx + 1) % flights.len) {
-        const flight = flights[flight_idx];
+    while (!au.W.should_close()) {
+        const flight = flights.next();
 
         const events = if (au.W.focused())
             au.wait_events_timeout(0.1)
@@ -243,7 +220,7 @@ pub fn main() !void {
 
         try render_cmd.beginCommandBuffer(&.{ .flags = .{ .one_time_submit_bit = true } });
 
-        try flight.frame.record_render(
+        try flight.ctx.record_render(
             render_cmd,
             image,
             view,