mac/vulkan: add support for visibility check for rendering

video/out/mac_common.swift

@@ -109,6 +109,10 @@ class MacCommon: Common {
         info.pointee.last_queue_display_time = next?.time ?? -1
     }
 
+    @objc func isVisible() -> Bool {
+        return window?.occlusionState.contains(.visible) ?? false
+    }
+
     override func displayLinkCallback(_ displayLink: CVDisplayLink,
                                       _ inNow: UnsafePointer<CVTimeStamp>,
                                       _ inOutputTime: UnsafePointer<CVTimeStamp>,

video/out/vulkan/context_mac.m

@@ -55,6 +55,12 @@ static int mac_vk_color_depth(struct ra_ctx *ctx)
     return 0;
 }
 
+static bool mac_vk_check_visible(struct ra_ctx *ctx)
+{
+    struct priv *p = ctx->priv;
+    return [p->vo_mac isVisible];
+}
+
 static bool mac_vk_init(struct ra_ctx *ctx)
 {
     struct priv *p = ctx->priv = talloc_zero(ctx, struct priv);
@@ -84,6 +90,7 @@ static bool mac_vk_init(struct ra_ctx *ctx)
         .swap_buffers = mac_vk_swap_buffers,
         .get_vsync = mac_vk_get_vsync,
         .color_depth = mac_vk_color_depth,
+        .check_visible = mac_vk_check_visible,
     };
 
     VkInstance inst = vk->vkinst->instance;