support screen size, rip out shared state

src/Window.zig

@@ -367,8 +367,11 @@ pub fn create(alloc: Allocator, loop: libuv.Loop, config: *const Config) !*Windo
 
     // Create our terminal grid with the initial window size
     const window_size = try window.getSize();
+    const screen_size: renderer.ScreenSize = .{
+        .width = window_size.width,
+        .height = window_size.height,
+    };
     var renderer_impl = try renderer.OpenGL.init(alloc, font_group);
-    try renderer_impl.setScreenSize(.{ .width = window_size.width, .height = window_size.height });
     renderer_impl.background = .{
         .r = config.background.r,
         .g = config.background.g,
@@ -381,10 +384,7 @@ pub fn create(alloc: Allocator, loop: libuv.Loop, config: *const Config) !*Windo
     };
 
     // Calculate our grid size based on known dimensions.
-    const grid_size = renderer.GridSize.init(
-        .{ .width = window_size.width, .height = window_size.height },
-        renderer_impl.cell_size,
-    );
+    const grid_size = renderer.GridSize.init(screen_size, renderer_impl.cell_size);
 
     // Set a minimum size that is cols=10 h=4. This matches Mac's Terminal.app
     // but is otherwise somewhat arbitrary.
@@ -486,6 +486,7 @@ pub fn create(alloc: Allocator, loop: libuv.Loop, config: *const Config) !*Windo
         .renderer_thread = render_thread,
         .renderer_state = .{
             .mutex = mutex,
+            .resize_screen = screen_size,
             .cursor = .{
                 .style = .blinking_block,
                 .visible = true,
@@ -516,7 +517,7 @@ 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);
@@ -718,18 +719,15 @@ fn sizeCallback(window: glfw.Window, width: i32, height: i32) void {
         .height = px_size.height,
     };
 
-    // Update our grid so that the projections on render are correct.
     const win = window.getUserPointer(Window) orelse return;
-    win.renderer.setScreenSize(screen_size) catch |err|
-        log.err("error updating grid screen size err={}", .{err});
+
+    // Resize usually forces a redraw
+    win.render_timer.schedule() catch |err|
+        log.err("error scheduling render timer in sizeCallback err={}", .{err});
 
     // Recalculate our grid size
     win.grid_size.update(screen_size, win.renderer.cell_size);
 
-    // Update the size of our terminal state
-    win.terminal.resize(win.alloc, win.grid_size.columns, win.grid_size.rows) catch |err|
-        log.err("error updating terminal size: {}", .{err});
-
     // Update the size of our pty
     win.pty.setSize(.{
         .ws_row = @intCast(u16, win.grid_size.rows),
@@ -738,14 +736,18 @@ fn sizeCallback(window: glfw.Window, width: i32, height: i32) void {
         .ws_ypixel = @intCast(u16, height),
     }) catch |err| log.err("error updating pty screen size err={}", .{err});
 
-    // Update our viewport for this context to be the entire window.
-    // OpenGL works in pixels, so we have to use the pixel size.
-    gl.viewport(0, 0, @intCast(i32, px_size.width), @intCast(i32, px_size.height)) catch |err|
-        log.err("error updating OpenGL viewport err={}", .{err});
+    // Enter the critical area that we want to keep small
+    {
+        win.renderer_state.mutex.lock();
+        defer win.renderer_state.mutex.unlock();
 
-    // Draw
-    win.render_timer.schedule() catch |err|
-        log.err("error scheduling render timer in sizeCallback err={}", .{err});
+        // We need to setup our render state to store our new pending size
+        win.renderer_state.resize_screen = screen_size;
+
+        // Update the size of our terminal state
+        win.terminal.resize(win.alloc, win.grid_size.columns, win.grid_size.rows) catch |err|
+            log.err("error updating terminal size: {}", .{err});
+    }
 }
 
 fn charCallback(window: glfw.Window, codepoint: u21) void {

src/renderer/OpenGL.zig

@@ -359,14 +359,24 @@ pub fn threadExit(self: *const OpenGL) void {
 pub fn render(
     self: *OpenGL,
     window: glfw.Window,
-    state: renderer.State,
+    state: *renderer.State,
 ) !void {
+    // Data we extract out of the critical area.
+    const Critical = struct {
+        devmode_data: ?*imgui.DrawData,
+        screen_size: ?renderer.ScreenSize,
+    };
+
     // Update all our data as tightly as possible within the mutex.
     var gl_bg = self.background;
-    {
+    const critical: Critical = critical: {
         state.mutex.lock();
         defer state.mutex.unlock();
 
+        // If we're resizing, then handle that now.
+        if (state.resize_screen) |size| try self.setScreenSize(size);
+        defer state.resize_screen = null;
+
         // Setup our cursor state
         self.cursor_visible = state.cursor.visible and !state.cursor.blink;
         self.cursor_style = CursorStyle.fromTerminal(state.cursor.style) orelse .box;
@@ -384,9 +394,33 @@ pub fn render(
             self.foreground = bg;
         }
 
+        // Build our GPU cells
         try self.rebuildCells(state.terminal);
         try self.finalizeCells(state.terminal);
-        if (state.devmode) |dm| if (dm.visible) try dm.update();
+
+        // Build our devmode draw data
+        const devmode_data = devmode_data: {
+            if (state.devmode) |dm| {
+                if (dm.visible) {
+                    try dm.update();
+                    break :devmode_data try dm.render();
+                }
+            }
+
+            break :devmode_data null;
+        };
+
+        break :critical .{
+            .devmode_data = devmode_data,
+            .screen_size = state.resize_screen,
+        };
+    };
+
+    // If we are resizing we need to update the viewport
+    if (critical.screen_size) |size| {
+        // Update our viewport for this context to be the entire window.
+        // OpenGL works in pixels, so we have to use the pixel size.
+        try gl.viewport(0, 0, @intCast(i32, size.width), @intCast(i32, size.height));
     }
 
     // Clear the surface
@@ -402,12 +436,9 @@ pub fn render(
     try self.draw();
 
     // If we have devmode, then render that
-    if (state.devmode) |dm| {
-        if (dm.visible) {
-            const data = try dm.render();
+    if (critical.devmode_data) |data| {
         imgui.ImplOpenGL3.renderDrawData(data);
     }
-    }
 
     // Swap our window buffers
     try window.swapBuffers();
@@ -783,7 +814,7 @@ pub fn updateCell(
 
 /// Set the screen size for rendering. This will update the projection
 /// used for the shader so that the scaling of the grid is correct.
-pub fn setScreenSize(self: *OpenGL, dim: renderer.ScreenSize) !void {
+fn setScreenSize(self: *OpenGL, dim: renderer.ScreenSize) !void {
     // Update the projection uniform within our shader
     const bind = try self.program.use();
     defer bind.unbind();

src/renderer/State.zig

@@ -3,6 +3,7 @@
 const std = @import("std");
 const DevMode = @import("../DevMode.zig");
 const terminal = @import("../terminal/main.zig");
+const renderer = @import("../renderer.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
@@ -11,7 +12,7 @@ const terminal = @import("../terminal/main.zig");
 mutex: *std.Thread.Mutex,
 
 /// A new screen size if the screen was resized.
-resize: ?Resize = null,
+resize_screen: ?renderer.ScreenSize,
 
 /// Cursor configuration for rendering
 cursor: Cursor,
@@ -36,5 +37,3 @@ pub const Cursor = struct {
     /// the cursor will not be rendered.
     blink: bool = false,
 };
-
-pub const Resize = struct {};

src/renderer/Thread.zig

@@ -31,7 +31,7 @@ window: glfw.Window,
 renderer: *renderer.OpenGL,
 
 /// Pointer to the shared state that is used to generate the final render.
-state: *const renderer.State,
+state: *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
@@ -40,7 +40,7 @@ pub fn init(
     alloc: Allocator,
     window: glfw.Window,
     renderer_impl: *renderer.OpenGL,
-    state: *const renderer.State,
+    state: *renderer.State,
 ) !Thread {
     // We always store allocator pointer on the loop data so that
     // handles can use our global allocator.
@@ -148,7 +148,7 @@ fn renderCallback(h: *libuv.Async) void {
         return;
     };
 
-    t.renderer.render(t.window, t.state.*) catch |err|
+    t.renderer.render(t.window, t.state) catch |err|
         log.warn("error rendering err={}", .{err});
 }