From 1b69fe485f455d160abd0d4c9c69d14ec98e21c6 Mon Sep 17 00:00:00 2001
From: jensj12 <jensheuseveldt@gmail.com>
Date: Thu, 13 Jul 2017 17:31:37 +0200
Subject: [PATCH] Show error if too high/low

Behaviour now matches that of the non-mountain land tool. Provide define
for min/max land height and fix a bug where the mountain tool would
incorrect raise/lower land.
---
 src/openrct2/world/map.c | 24 ++++++++++++++++++++----
 src/openrct2/world/map.h |  3 +++
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/openrct2/world/map.c b/src/openrct2/world/map.c
index 0e85e0621d..bfc7e927ee 100644
--- a/src/openrct2/world/map.c
+++ b/src/openrct2/world/map.c
@@ -1512,21 +1512,21 @@ static money32 map_set_land_height(sint32 flags, sint32 x, sint32 y, sint32 heig
         return MONEY32_UNDEFINED;
     }
 
-    if (height < 2) {
+    if (height < MINIMUM_LAND_HEIGHT) {
         gGameCommandErrorText = STR_TOO_LOW;
         return MONEY32_UNDEFINED;
     }
 
     // Divide by 2 and subtract 7 to get the in-game units.
-    if (height > 142) {
+    if (height > MAXIMUM_LAND_HEIGHT) {
         gGameCommandErrorText = STR_TOO_HIGH;
         return MONEY32_UNDEFINED;
-    } else if (height > 140 && (style & 0x1F) != 0) {
+    } else if (height > MAXIMUM_LAND_HEIGHT - 2 && (style & 0x1F) != 0) {
         gGameCommandErrorText = STR_TOO_HIGH;
         return MONEY32_UNDEFINED;
     }
 
-    if (height == 140 && (style & 0x10)) {
+    if (height == MAXIMUM_LAND_HEIGHT - 2 && (style & 0x10)) {
         gGameCommandErrorText = STR_TOO_HIGH;
         return MONEY32_UNDEFINED;
     }
@@ -2220,10 +2220,18 @@ static money32 smooth_land(sint32 flags, sint32 centreX, sint32 centreY, sint32
         if (commandType == GAME_COMMAND_RAISE_LAND) {
             minHeight += 2;
             maxHeight += 2;
+            if (minHeight > MAXIMUM_LAND_HEIGHT) {
+                gGameCommandErrorText = STR_TOO_HIGH;
+                return MONEY32_UNDEFINED;
+            }
         }
         else {
             maxHeight -= 2;
             minHeight -= 2;
+            if (maxHeight < MINIMUM_LAND_HEIGHT) {
+                gGameCommandErrorText = STR_TOO_LOW;
+                return MONEY32_UNDEFINED;
+            }
         }
     }
     else
@@ -2237,6 +2245,10 @@ static money32 smooth_land(sint32 flags, sint32 centreX, sint32 centreY, sint32
                 newBaseZ += 2;
                 newSlope &= ~0x20;
             }
+			if (map_get_corner_height(newBaseZ, newSlope, command & 0xFF) > MAXIMUM_LAND_HEIGHT) {
+				gGameCommandErrorText = STR_TOO_HIGH;
+				return MONEY32_UNDEFINED;
+			}
         }
         else {
             newSlope = map_element_lower_styles[command & 0xFF][newSlope];
@@ -2244,6 +2256,10 @@ static money32 smooth_land(sint32 flags, sint32 centreX, sint32 centreY, sint32
                 newBaseZ -= 2;
                 newSlope &= ~0x20;
             }
+			if (newBaseZ < MINIMUM_LAND_HEIGHT) {
+				gGameCommandErrorText = STR_TOO_LOW;
+				return MONEY32_UNDEFINED;
+			}
         }
     }
 
diff --git a/src/openrct2/world/map.h b/src/openrct2/world/map.h
index bac15d97ba..487938da0c 100644
--- a/src/openrct2/world/map.h
+++ b/src/openrct2/world/map.h
@@ -273,6 +273,9 @@ enum
 #define MAP_ELEM_TRACK_SEQUENCE_SEQUENCE_MASK 0x0F
 #define MAP_ELEM_TRACK_SEQUENCE_TAKING_PHOTO_MASK 0xF0
 
+#define MINIMUM_LAND_HEIGHT 2
+#define MAXIMUM_LAND_HEIGHT 142
+
 #define MINIMUM_MAP_SIZE_TECHNICAL 15
 #define MAXIMUM_MAP_SIZE_TECHNICAL 256
 #define MINIMUM_MAP_SIZE_PRACTICAL (MINIMUM_MAP_SIZE_TECHNICAL-2)