SDL: Android: add comment to set render target to NULL when going to background (bug #4041)

From 0ad606b48d07122cdd9767aaae93f99cf1d18a3c Mon Sep 17 00:00:00 2001
From: Sylvain <[EMAIL REDACTED]>
Date: Mon, 14 Mar 2022 10:43:18 +0100
Subject: [PATCH] Android: add comment to set render target to NULL when going
 to background (bug #4041)

---
 docs/README-android.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/docs/README-android.md b/docs/README-android.md
index 9ad8627b330..39db67ad6d0 100644
--- a/docs/README-android.md
+++ b/docs/README-android.md
@@ -206,6 +206,9 @@ You should not use the SDL renderer API while the app going in background:
     after you read this message, GL context gets backed-up and you should not
     use the SDL renderer API.
 
+    When this event is received, you have to set the render target to NULL, if you're using it.
+    (eg call SDL_SetRenderTarget(renderer, NULL))
+
 - SDL_APP_DIDENTERFOREGROUND:
    GL context is restored, and the SDL renderer API is available (unless you
    receive SDL_RENDER_DEVICE_RESET).