From c6aab6f56ccbc41563ef12e5fa1ed47082dffec6 Mon Sep 17 00:00:00 2001
From: emersion <contact@emersion.fr>
Date: Sun, 21 Jan 2018 11:11:25 +0100
Subject: Add docs and comments

---
 include/rootston/output.h | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'include/rootston/output.h')

diff --git a/include/rootston/output.h b/include/rootston/output.h
index c0022d1a..89fe1d82 100644
--- a/include/rootston/output.h
+++ b/include/rootston/output.h
@@ -5,6 +5,11 @@
 #include <pixman.h>
 #include <wayland-server.h>
 
+/**
+ * Damage tracking requires to keep track of previous frames' damage. To allow
+ * damage tracking to work with triple buffering, an history of two frames is
+ * required.
+ */
 #define ROOTS_OUTPUT_PREVIOUS_DAMAGE_LEN 2
 
 struct roots_desktop;
@@ -20,6 +25,7 @@ struct roots_output {
 	pixman_region32_t damage;
 	bool frame_pending;
 
+	// circular queue for previous damage
 	pixman_region32_t previous_damage[ROOTS_OUTPUT_PREVIOUS_DAMAGE_LEN];
 	size_t previous_damage_idx;
 
-- 
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