From b5d543705de4ea42407db9e2d49ae03f3ae5cf14 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Tue, 13 Feb 2024 20:07:41 -0800
Subject: [PATCH] renderer/metal: free resources when occluded

---
 src/renderer/Metal.zig  | 18 ++++++++++++++++++
 src/renderer/Thread.zig |  3 +++
 2 files changed, 21 insertions(+)

diff --git a/src/renderer/Metal.zig b/src/renderer/Metal.zig
index 4a1f0f131..8296176d4 100644
--- a/src/renderer/Metal.zig
+++ b/src/renderer/Metal.zig
@@ -509,6 +509,19 @@ pub fn setFocus(self: *Metal, focus: bool) !void {
     self.focused = focus;
 }
 
+/// Callback when the view visibility changes, i.e. if a window is on
+/// another workspace, behind a window, etc.
+pub fn setVisible(self: *Metal, visible: bool) !void {
+    //if (true) return;
+    if (!visible) {
+        if (self.visible_resources) |*v| {
+            log.debug("view occluded, deallocating GPU resources", .{});
+            v.deinit(self.alloc);
+            self.visible_resources = null;
+        }
+    }
+}
+
 /// Set the new font size.
 ///
 /// Must be called on the render thread.
@@ -712,6 +725,7 @@ pub fn drawFrame(self: *Metal, surface: *apprt.Surface) !void {
     // Get our cached resources. If we don't have them, then we need to
     // create them. If we fail to create them, mark the renderer as unhealthy.
     const resources: *VisibleResources = if (self.visible_resources) |*v| v else resources: {
+        log.debug("view is visible, allocating GPU resources", .{});
         const resources = VisibleResources.init(self) catch |err| {
             self.setHealth(.unhealthy);
             return err;
@@ -2226,6 +2240,10 @@ const VisibleResources = struct {
         const texture_color = try initAtlasTexture(m.device, &m.font_group.atlas_color);
         errdefer deinitMTLResource(texture_color);
 
+        // Mark our atlas as modified so the textures are synced
+        m.font_group.atlas_greyscale.modified = true;
+        m.font_group.atlas_color.modified = true;
+
         return .{
             .shaders = shaders,
             .buf_cells = buf_cells,
diff --git a/src/renderer/Thread.zig b/src/renderer/Thread.zig
index 113f6761c..84f1940f5 100644
--- a/src/renderer/Thread.zig
+++ b/src/renderer/Thread.zig
@@ -250,6 +250,9 @@ fn drainMailbox(self: *Thread) !void {
                 // Set our visible state
                 self.flags.visible = v;
 
+                // Set it on the renderer
+                try self.renderer.setVisible(v);
+
                 // If we became visible then we immediately trigger a draw.
                 // We don't need to update frame data because that should
                 // still be happening.