From 3fbcfeeb4b80e6c068aa9497e00d54878b791e3f Mon Sep 17 00:00:00 2001
From: Loek Le Blansch <loek@pipeframe.xyz>
Date: Mon, 19 Aug 2024 16:31:54 +0200
Subject: more successful message fiddling

---
 src/frontend/qt_sdl/LocalMP.cpp | 40 +++++++++++++++++++++-------------------
 1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/src/frontend/qt_sdl/LocalMP.cpp b/src/frontend/qt_sdl/LocalMP.cpp
index 906f4d4..0ca5921 100644
--- a/src/frontend/qt_sdl/LocalMP.cpp
+++ b/src/frontend/qt_sdl/LocalMP.cpp
@@ -463,10 +463,6 @@ int SendPacketGeneric(u32 type, u8* packet, int len, u64 timestamp)
     pktheader.Length = len;
     pktheader.Timestamp = timestamp;
 
-#ifdef VSR_MESSAGE_FIDDLING
-    static int package_idx = 0;
-#endif
-
     type &= 0xFFFF;
     int nfifo = (type == 2) ? 1 : 0;
     // NOTE: this is the ni-fi packet header, altering this header in any way
@@ -481,24 +477,30 @@ int SendPacketGeneric(u32 type, u8* packet, int len, u64 timestamp)
 #ifdef VSR_MESSAGE_FIDDLING
         // if message packet (has size 222 w/o ni-fi header)
         if (fiddle && len == 222) {
-            // if fresh message (do not count resends)
-            if (packet[0x02] == 0x02) {
-                // corrupt all pixels in every nth package
-                package_idx = (package_idx + 1) % 10;
+            const u8 fill = 0x33; // hot pink (#eb00eb)
+            unsigned safe = 0;
+
+            // if content offset == 0 there is some very important info at the
+            // start of the message which must stay intact 
+            u16 content_offset = *(u16*)(packet + 0x32);
+            if (content_offset == 0) {
+                safe = 0x24; // don't touch the first 0x24 bytes
             }
 
-            if (true || package_idx == 0) {
-                // mainWindow->osdAddMessage(0x00ff00, "oops!");
-                // NOTE: packet indexes are after NIFI header!
-                for (size_t i = 0; i < 0x80; i++) {
-                    packet[0x3e + i] = 0x11;
-                }
-                // packet[0x3e + 0x00] = 0x13;
-                // packet[0x3e + 0x01] = 0x13;
-
-                // packet[0x3e + 0x02] = 0x33;
-                // packet[0x3e + 0x04] = 0x33;
+            for (size_t i = safe; i < 0xa0; i++) {
+                packet[0x36 + i] = fill;
             }
+
+            // // mainWindow->osdAddMessage(0x00ff00, "oops!");
+            // // NOTE: packet indexes are after NIFI header!
+            // for (size_t i = 0; i < 0x80; i++) {
+            //     packet[0x3e + i] = 0x11;
+            // }
+            // // packet[0x3e + 0x00] = 0x13;
+            // // packet[0x3e + 0x01] = 0x13;
+
+            // // packet[0x3e + 0x02] = 0x33;
+            // // packet[0x3e + 0x04] = 0x33;
         }
 #endif
 
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