run rendering on another real thread (still bugs)

pkg/libuv/main.zig

@@ -1,6 +1,7 @@
 const std = @import("std");
 const stream = @import("stream.zig");
 
+pub const c = @import("c.zig");
 pub const Loop = @import("Loop.zig");
 pub const Async = @import("Async.zig");
 pub const Idle = @import("Idle.zig");

src/Window.zig

@@ -59,6 +59,12 @@ renderer: renderer.OpenGL,
 /// The render state
 renderer_state: renderer.State,
 
+/// The renderer thread manager
+renderer_thread: renderer.Thread,
+
+/// The actual thread
+renderer_thr: std.Thread,
+
 /// The underlying pty for this window.
 pty: Pty,
 
@@ -450,6 +456,15 @@ pub fn create(alloc: Allocator, loop: libuv.Loop, config: *const Config) !*Windo
     mutex.* = .{};
     errdefer alloc.destroy(mutex);
 
+    // Create the renderer thread
+    var render_thread = try renderer.Thread.init(
+        alloc,
+        window,
+        &self.renderer,
+        &self.renderer_state,
+    );
+    errdefer render_thread.deinit();
+
     self.* = .{
         .alloc = alloc,
         .alloc_io_arena = io_arena,
@@ -459,6 +474,7 @@ pub fn create(alloc: Allocator, loop: libuv.Loop, config: *const Config) !*Windo
         .cursor = cursor,
         .focused = false,
         .renderer = renderer_impl,
+        .renderer_thread = render_thread,
         .renderer_state = .{
             .mutex = mutex,
             .cursor = .{
@@ -469,6 +485,7 @@ pub fn create(alloc: Allocator, loop: libuv.Loop, config: *const Config) !*Windo
             .terminal = &self.terminal,
             .devmode = if (!DevMode.enabled) null else &DevMode.instance,
         },
+        .renderer_thr = undefined,
         .pty = pty,
         .command = cmd,
         .mouse = .{},
@@ -489,7 +506,7 @@ pub fn create(alloc: Allocator, loop: libuv.Loop, config: *const Config) !*Windo
 
     // Setup our callbacks and user data
     window.setUserPointer(self);
-    window.setSizeCallback(sizeCallback);
+    //window.setSizeCallback(sizeCallback);
     window.setCharCallback(charCallback);
     window.setKeyCallback(keyCallback);
     window.setFocusCallback(focusCallback);
@@ -537,10 +554,33 @@ pub fn create(alloc: Allocator, loop: libuv.Loop, config: *const Config) !*Windo
         DevMode.instance.window = self;
     }
 
+    // Unload our context prior to switching over to the renderer thread
+    // because OpenGL requires it to be unloaded.
+    gl.glad.unload();
+    try glfw.makeContextCurrent(null);
+
+    // Start our renderer thread
+    self.renderer_thr = try std.Thread.spawn(
+        .{},
+        renderer.Thread.threadMain,
+        .{&self.renderer_thread},
+    );
+
     return self;
 }
 
 pub fn destroy(self: *Window) void {
+    {
+        // Stop rendering thread
+        self.renderer_thread.stop.send() catch |err|
+            log.err("error notifying renderer thread to stop, may stall err={}", .{err});
+        self.renderer_thr.join();
+
+        // We need to become the active rendering thread again
+        self.renderer.threadEnter(self.window) catch unreachable;
+        self.renderer_thread.deinit();
+    }
+
     if (DevMode.enabled) {
         // Clear the window
         DevMode.instance.window = null;
@@ -1470,6 +1510,10 @@ fn cursorTimerCallback(t: *libuv.Timer) void {
 
     const win = t.getData(Window) orelse return;
 
+    // We are modifying renderer state from here on out
+    win.renderer_state.mutex.lock();
+    defer win.renderer_state.mutex.unlock();
+
     // If the cursor is currently invisible, then we do nothing. Ideally
     // in this state the timer would be cancelled but no big deal.
     if (!win.renderer_state.cursor.visible) return;
@@ -1589,9 +1633,9 @@ fn renderTimerCallback(t: *libuv.Timer) void {
 
     const win = t.getData(Window).?;
 
-    // Render
-    win.renderer.render(win.window, win.renderer_state) catch |err|
-        log.warn("error rendering err={}", .{err});
+    // Trigger a render
+    win.renderer_thread.wakeup.send() catch |err|
+        log.err("error sending render notification err={}", .{err});
 
     // Record our run
     win.render_timer.tick();

src/renderer/OpenGL.zig

@@ -325,7 +325,9 @@ pub fn deinit(self: *OpenGL) void {
 }
 
 /// Callback called by renderer.Thread when it begins.
-pub fn threadEnter(window: glfw.Window) !void {
+pub fn threadEnter(self: *const OpenGL, window: glfw.Window) !void {
+    _ = self;
+
     // We need to make the OpenGL context current. OpenGL requires
     // that a single thread own the a single OpenGL context (if any). This
     // ensures that the context switches over to our thread. Important:
@@ -350,7 +352,9 @@ pub fn threadEnter(window: glfw.Window) !void {
 }
 
 /// Callback called by renderer.Thread when it exits.
-pub fn threadExit() void {
+pub fn threadExit(self: *const OpenGL) void {
+    _ = self;
+
     gl.glad.unload();
     glfw.makeContextCurrent(null) catch {};
 }

src/renderer/State.zig

@@ -0,0 +1,40 @@
+//! This is the render state that is given to a renderer.
+
+const std = @import("std");
+const DevMode = @import("../DevMode.zig");
+const terminal = @import("../terminal/main.zig");
+
+/// The mutex that must be held while reading any of the data in the
+/// members of this state. Note that the state itself is NOT protected
+/// by the mutex and is NOT thread-safe, only the members values of the
+/// state (i.e. the terminal, devmode, etc. values).
+mutex: *std.Thread.Mutex,
+
+/// A new screen size if the screen was resized.
+resize: ?Resize = null,
+
+/// Cursor configuration for rendering
+cursor: Cursor,
+
+/// The terminal data.
+terminal: *terminal.Terminal,
+
+/// The devmode data.
+devmode: ?*const DevMode = null,
+
+pub const Cursor = struct {
+    /// Current cursor style. This can be set by escape sequences. To get
+    /// the default style, the config has to be referenced.
+    style: terminal.CursorStyle = .default,
+
+    /// Whether the cursor is visible at all. This should not be used for
+    /// "blink" settings, see "blink" for that. This is used to turn the
+    /// cursor ON or OFF.
+    visible: bool = true,
+
+    /// Whether the cursor is currently blinking. If it is blinking, then
+    /// the cursor will not be rendered.
+    blink: bool = false,
+};
+
+pub const Resize = struct {};

src/renderer/Thread.zig

@@ -10,7 +10,7 @@ const renderer = @import("../renderer.zig");
 const gl = @import("../opengl.zig");
 
 const Allocator = std.mem.Allocator;
-const log = std.log.named(.renderer_thread);
+const log = std.log.scoped(.renderer_thread);
 
 /// The main event loop for the application. The user data of this loop
 /// is always the allocator used to create the loop. This is a convenience
@@ -21,10 +21,27 @@ loop: libuv.Loop,
 /// any thread.
 wakeup: libuv.Async,
 
+/// This can be used to stop the renderer on the next loop iteration.
+stop: libuv.Async,
+
+/// The windo we're rendering to.
+window: glfw.Window,
+
+/// The underlying renderer implementation.
+renderer: *renderer.OpenGL,
+
+/// Pointer to the shared state that is used to generate the final render.
+state: *const renderer.State,
+
 /// Initialize the thread. This does not START the thread. This only sets
 /// up all the internal state necessary prior to starting the thread. It
 /// is up to the caller to start the thread with the threadMain entrypoint.
-pub fn init(alloc: Allocator) !Thread {
+pub fn init(
+    alloc: Allocator,
+    window: glfw.Window,
+    renderer_impl: *renderer.OpenGL,
+    state: *const renderer.State,
+) !Thread {
     // We always store allocator pointer on the loop data so that
     // handles can use our global allocator.
     const allocPtr = try alloc.create(Allocator);
@@ -37,10 +54,17 @@ pub fn init(alloc: Allocator) !Thread {
     loop.setData(allocPtr);
 
     // This async handle is used to "wake up" the renderer and force a render.
-    var async_h = try libuv.Async.init(alloc, loop, (struct {
-        fn callback(_: *libuv.Async) void {}
+    var wakeup_h = try libuv.Async.init(alloc, loop, renderCallback);
+    errdefer wakeup_h.close((struct {
+        fn callback(h: *libuv.Async) void {
+            const loop_alloc = h.loop().getData(Allocator).?.*;
+            h.deinit(loop_alloc);
+        }
     }).callback);
-    errdefer async_h.close((struct {
+
+    // This async handle is used to stop the loop and force the thread to end.
+    var stop_h = try libuv.Async.init(alloc, loop, stopCallback);
+    errdefer stop_h.close((struct {
         fn callback(h: *libuv.Async) void {
             const loop_alloc = h.loop().getData(Allocator).?.*;
             h.deinit(loop_alloc);
@@ -48,9 +72,12 @@ pub fn init(alloc: Allocator) !Thread {
     }).callback);
 
     return Thread{
-        .alloc = alloc,
         .loop = loop,
-        .notifier = async_h,
+        .wakeup = wakeup_h,
+        .stop = stop_h,
+        .window = window,
+        .renderer = renderer_impl,
+        .state = state,
     };
 }
 
@@ -61,6 +88,20 @@ pub fn deinit(self: *Thread) void {
     const alloc_ptr = self.loop.getData(Allocator).?;
     const alloc = alloc_ptr.*;
 
+    // Schedule our handles to close
+    self.stop.close((struct {
+        fn callback(h: *libuv.Async) void {
+            const handle_alloc = h.loop().getData(Allocator).?.*;
+            h.deinit(handle_alloc);
+        }
+    }).callback);
+    self.wakeup.close((struct {
+        fn callback(h: *libuv.Async) void {
+            const handle_alloc = h.loop().getData(Allocator).?.*;
+            h.deinit(handle_alloc);
+        }
+    }).callback);
+
     // Run the loop one more time, because destroying our other things
     // like windows usually cancel all our event loop stuff and we need
     // one more run through to finalize all the closes.
@@ -74,40 +115,54 @@ pub fn deinit(self: *Thread) void {
 }
 
 /// The main entrypoint for the thread.
-pub fn threadMain(
-    window: glfw.Window,
-    renderer_impl: *const renderer.OpenGL,
-) void {
+pub fn threadMain(self: *Thread) void {
     // Call child function so we can use errors...
-    threadMain_(
-        window,
-        renderer_impl,
-    ) catch |err| {
+    self.threadMain_() catch |err| {
         // In the future, we should expose this on the thread struct.
         log.warn("error in renderer err={}", .{err});
     };
 }
 
-fn threadMain_(
-    self: *const Thread,
-    window: glfw.Window,
-    renderer_impl: *const renderer.OpenGL,
-) !void {
-    const Renderer = switch (@TypeOf(renderer_impl)) {
-        .Pointer => |p| p.child,
-        .Struct => |s| s,
-    };
-
+fn threadMain_(self: *Thread) !void {
     // Run our thread start/end callbacks. This is important because some
     // renderers have to do per-thread setup. For example, OpenGL has to set
     // some thread-local state since that is how it works.
-    if (@hasDecl(Renderer, "threadEnter")) try renderer_impl.threadEnter(window);
-    defer if (@hasDecl(Renderer, "threadExit")) renderer_impl.threadExit();
+    const Renderer = RendererType();
+    if (@hasDecl(Renderer, "threadEnter")) try self.renderer.threadEnter(self.window);
+    defer if (@hasDecl(Renderer, "threadExit")) self.renderer.threadExit();
 
-    // Setup our timer handle which is used to perform the actual render.
-    // TODO
+    // Set up our async handler to support rendering
+    self.wakeup.setData(self);
+    defer self.wakeup.setData(null);
 
     // Run
     log.debug("starting renderer thread", .{});
-    try self.loop.run(.default);
+    defer log.debug("exiting renderer thread", .{});
+    _ = try self.loop.run(.default);
+}
+
+fn renderCallback(h: *libuv.Async) void {
+    const t = h.getData(Thread) orelse {
+        // This shouldn't happen so we log it.
+        log.warn("render callback fired without data set", .{});
+        return;
+    };
+
+    t.renderer.render(t.window, t.state.*) catch |err|
+        log.warn("error rendering err={}", .{err});
+}
+
+fn stopCallback(h: *libuv.Async) void {
+    h.loop().stop();
+}
+
+// This is unnecessary right now but is logic we'll need for when we
+// abstract renderers out.
+fn RendererType() type {
+    const self: Thread = undefined;
+    return switch (@typeInfo(@TypeOf(self.renderer))) {
+        .Pointer => |p| p.child,
+        .Struct => |s| s,
+        else => unreachable,
+    };
 }