From 21338e61784eebea1ae850a1cdb3bcf049de5924 Mon Sep 17 00:00:00 2001
From: Yuval Tassa <tassa@google.com>
Date: Wed, 23 Mar 2022 11:40:29 -0700
Subject: [PATCH] Fix bug in simulate where pressing '[' or ']' when a model is
 not loaded will causes a crash.

PiperOrigin-RevId: 436791755
Change-Id: I0bfec45eecef4bbb8db8f47f0d1e8a0276399b8f
---
 sample/simulate.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sample/simulate.cc b/sample/simulate.cc
index 34a28045..ff0f15ef 100644
--- a/sample/simulate.cc
+++ b/sample/simulate.cc
@@ -1554,7 +1554,7 @@ void uiEvent(mjuiState* state) {
       break;
 
     case ']':                   // cycle up fixed cameras
-      if (m->ncam) {
+      if (m && m->ncam) {
         cam.type = mjCAMERA_FIXED;
         // settings.camera = {0 or 1} are reserved for the free and tracking cameras
         if (settings.camera < 2 || settings.camera == 2 + m->ncam-1) {
@@ -1568,7 +1568,7 @@ void uiEvent(mjuiState* state) {
       break;
 
     case '[':                   // cycle down fixed cameras
-      if (m->ncam) {
+      if (m && m->ncam) {
         cam.type = mjCAMERA_FIXED;
         // settings.camera = {0 or 1} are reserved for the free and tracking cameras
         if (settings.camera <= 2) {