From 1ccff12b541a23c06eab8a32dcafe0d76a6478ea Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <tridge@samba.org>
Date: Fri, 17 Aug 2012 14:21:43 +1000
Subject: [PATCH] SITL: added SIM_ENGINE_MUL

this allows for simulated engine failures
---
 libraries/Desktop/support/sitl.cpp | 6 ++++++
 libraries/SITL/SITL.cpp            | 1 +
 libraries/SITL/SITL.h              | 1 +
 3 files changed, 8 insertions(+)

diff --git a/libraries/Desktop/support/sitl.cpp b/libraries/Desktop/support/sitl.cpp
index 069dbca932..efc39c930a 100644
--- a/libraries/Desktop/support/sitl.cpp
+++ b/libraries/Desktop/support/sitl.cpp
@@ -187,6 +187,12 @@ static void sitl_simulator_output(void)
 	}
 
 	if (!desktop_state.quadcopter) {
+		// add in engine multiplier
+		if (pwm[2] > 1000) {
+			pwm[2] = ((pwm[2]-1000) * sitl.engine_mul) + 1000;
+			if (pwm[2] > 2000) pwm[2] = 2000;
+		}
+
 		// 400kV motor, 16V
 		sitl_motor_speed[0] = ((pwm[2]-1000)/1000.0) * 400 * 16 / 60.0;
 	} else {
diff --git a/libraries/SITL/SITL.cpp b/libraries/SITL/SITL.cpp
index 31fc24d8a5..491f7253c5 100644
--- a/libraries/SITL/SITL.cpp
+++ b/libraries/SITL/SITL.cpp
@@ -23,6 +23,7 @@ const AP_Param::GroupInfo SITL::var_info[] PROGMEM = {
     AP_GROUPINFO("DRIFT_SPEED",5, SITL,  drift_speed, 0.2),
     AP_GROUPINFO("DRIFT_TIME", 6, SITL,  drift_time,  5),
     AP_GROUPINFO("GPS_DELAY",  7, SITL,  gps_delay,   4),
+    AP_GROUPINFO("ENGINE_MUL", 8, SITL,  engine_mul,  1),
     AP_GROUPEND
 };
 
diff --git a/libraries/SITL/SITL.h b/libraries/SITL/SITL.h
index c1c7c1f14d..9f7e65488c 100644
--- a/libraries/SITL/SITL.h
+++ b/libraries/SITL/SITL.h
@@ -50,6 +50,7 @@ public:
 
 	AP_Float drift_speed; // degrees/second/minute
 	AP_Float drift_time;  // period in minutes
+    AP_Float engine_mul;  // engine multiplier
 	AP_Int8  gps_disable; // disable simulated GPS
 	AP_Int8  gps_delay;   // delay in samples