From f157f01f71bda8ffe96b8f884d3954f358e01368 Mon Sep 17 00:00:00 2001
From: Ramen2X <rmn@legoisland.org>
Date: Thu, 28 Mar 2024 10:27:44 -0400
Subject: [PATCH] implement/match UpdateLightPosition() (#744)

---
 LEGO1/lego/legoomni/include/legoutils.h      |  2 +-
 LEGO1/lego/legoomni/src/common/legoutils.cpp | 34 +++++++++++++++++---
 LEGO1/lego/legoomni/src/worlds/isle.cpp      |  4 +--
 3 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/LEGO1/lego/legoomni/include/legoutils.h b/LEGO1/lego/legoomni/include/legoutils.h
index cf8e57ea..5d495665 100644
--- a/LEGO1/lego/legoomni/include/legoutils.h
+++ b/LEGO1/lego/legoomni/include/legoutils.h
@@ -25,7 +25,7 @@ void FUN_1003ef00(MxBool);
 void SetAppCursor(WPARAM p_wparam);
 MxBool FUN_1003ef60();
 MxBool RemoveFromWorld(MxAtomId& p_entityAtom, MxS32 p_entityId, MxAtomId& p_worldAtom, MxS32 p_worldEntityId);
-MxS32 FUN_1003f050(MxS32);
+MxS32 UpdateLightPosition(MxS32 p_value);
 void SetLightPosition(MxU32);
 LegoNamedTexture* ReadNamedTexture(LegoFile* p_file);
 void FUN_1003f540(LegoFile* p_file, const char* p_filename);
diff --git a/LEGO1/lego/legoomni/src/common/legoutils.cpp b/LEGO1/lego/legoomni/src/common/legoutils.cpp
index fc0585f6..8491f736 100644
--- a/LEGO1/lego/legoomni/src/common/legoutils.cpp
+++ b/LEGO1/lego/legoomni/src/common/legoutils.cpp
@@ -339,11 +339,37 @@ MxBool FUN_1003ef60()
 	return FALSE;
 }
 
-// STUB: LEGO1 0x1003f050
-MxS32 FUN_1003f050(MxS32)
+// FUNCTION: LEGO1 0x1003f050
+MxS32 UpdateLightPosition(MxS32 p_value)
 {
-	// TODO
-	return 0;
+	// This function updates the light position
+	// relatively by the amount passed in p_value.
+	// Because it operates relatively, it does not set
+	// the light position to an arbitrary value.
+
+	MxS32 lightPosition = atoi(VariableTable()->GetVariable("lightposition"));
+
+	if (p_value > 0) {
+		lightPosition += 1;
+		if (lightPosition > 5) {
+			lightPosition = 5;
+		}
+	}
+	else {
+		lightPosition -= 1;
+		if (lightPosition < 0) {
+			lightPosition = 0;
+		}
+	}
+
+	SetLightPosition(lightPosition);
+
+	char lightPositionBuffer[32];
+	sprintf(lightPositionBuffer, "%d", lightPosition);
+
+	VariableTable()->SetVariable("lightposition", lightPositionBuffer);
+
+	return lightPosition;
 }
 
 // STUB: LEGO1 0x1003f0d0
diff --git a/LEGO1/lego/legoomni/src/worlds/isle.cpp b/LEGO1/lego/legoomni/src/worlds/isle.cpp
index cf692fd9..bf5f85a8 100644
--- a/LEGO1/lego/legoomni/src/worlds/isle.cpp
+++ b/LEGO1/lego/legoomni/src/worlds/isle.cpp
@@ -399,11 +399,11 @@ MxLong Isle::HandleClick(LegoControlManagerEvent& p_param)
 			FUN_10031590();
 			break;
 		case IsleScript::c_Observe_GlobeLArrow_Ctl:
-			FUN_1003f050(-1);
+			UpdateLightPosition(-1);
 			FUN_10031590();
 			break;
 		case IsleScript::c_Observe_GlobeRArrow_Ctl:
-			FUN_1003f050(1);
+			UpdateLightPosition(1);
 			FUN_10031590();
 			break;
 		case IsleScript::c_Observe_Draw1_Ctl: