SDL: Fix touchid assertion faliure on emscripten

From 4022682c284a049ba696ad49777ac39da7de36fb Mon Sep 17 00:00:00 2001
From: Cyao <[EMAIL REDACTED]>
Date: Thu, 23 May 2024 18:05:57 +0200
Subject: [PATCH] Fix touchid assertion faliure on emscripten

---
 src/video/emscripten/SDL_emscriptenevents.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/video/emscripten/SDL_emscriptenevents.c b/src/video/emscripten/SDL_emscriptenevents.c
index 868be8b3d9567..a1b1dbdaf4410 100644
--- a/src/video/emscripten/SDL_emscriptenevents.c
+++ b/src/video/emscripten/SDL_emscriptenevents.c
@@ -762,7 +762,7 @@ static EM_BOOL Emscripten_HandleTouch(int eventType, const EmscriptenTouchEvent
             continue;
         }
 
-        id = touchEvent->touches[i].identifier;
+        id = touchEvent->touches[i].identifier + 1;
         if (client_w <= 1) {
             x = 0.5f;
         } else {