From fffdf4a6dd69f16176698f8b42db7dfe2a054e26 Mon Sep 17 00:00:00 2001
From: Arne Dußin
Date: Thu, 4 Feb 2021 21:57:09 +0100
Subject: Fix crash when drawing rect with no area

---
 src/client/tool/rect_room_tool.rs | 37 +++++++++++++++++++++----------------
 src/math/rect.rs                  |  9 +++++++++
 2 files changed, 30 insertions(+), 16 deletions(-)

(limited to 'src')

diff --git a/src/client/tool/rect_room_tool.rs b/src/client/tool/rect_room_tool.rs
index 41f2a91..60bf246 100644
--- a/src/client/tool/rect_room_tool.rs
+++ b/src/client/tool/rect_room_tool.rs
@@ -6,9 +6,11 @@ use super::Tool;
 use crate::client::colours::DEFAULT_COLOURS;
 use crate::client::map::Map;
 use crate::client::transform::Transform;
+use crate::client::FLOAT_MARGIN;
 use crate::math::{Rect, Vec2};
 use crate::net::{Cargo, Connection};
 use crate::world::Room;
+use float_cmp::ApproxEq;
 use raylib::core::drawing::{RaylibDraw, RaylibDrawHandle};
 
 /// The tool to create simple, rectangular rooms.
@@ -29,6 +31,19 @@ impl RectRoomTool {
     }
 }
 
+/* Try to create a rectangle from the given points, but only if they don't create
+ * a rectangle with no area.
+ */
+fn try_into_bounding_rect(pos1: Vec2<f64>, pos2: Vec2<f64>) -> Option<Rect<f64>> {
+    let bounding_rect = Rect::bounding_rect(pos1, pos2);
+
+    if !bounding_rect.area().approx_eq(0., FLOAT_MARGIN) {
+        Some(bounding_rect)
+    } else {
+        None
+    }
+}
+
 impl Tool for RectRoomTool {
     fn deactivate(&mut self) {
         self.unfinished_rect = None;
@@ -57,15 +72,10 @@ impl Tool for RectRoomTool {
     ) {
         // Try to finish the rectangle if it has been started.
         if let Some((pos1, pos2)) = self.unfinished_rect {
-            if pos1 == pos2 {
-                warn!("Cannot place rectangle with start and endpoint being the same");
-                return;
+            if let Some(rect) = try_into_bounding_rect(pos1, pos2) {
+                server.send(Cargo::AddRoom(Room::new(rect.into())));
+                self.unfinished_rect = None;
             }
-
-            server.send(Cargo::AddRoom(Room::new(
-                Rect::bounding_rect(pos1, pos2).into(),
-            )));
-            self.unfinished_rect = None;
         } else {
             self.unfinished_rect = Some((*mouse_pos_m, *mouse_pos_m));
         }
@@ -73,15 +83,10 @@ impl Tool for RectRoomTool {
 
     fn finish(&mut self, _map: &mut Map, server: &Connection<Cargo>) {
         if let Some((pos1, pos2)) = self.unfinished_rect {
-            if pos1 == pos2 {
-                warn!("Cannot place rectangle with start and endpoint being the same");
-                return;
+            if let Some(rect) = try_into_bounding_rect(pos1, pos2) {
+                server.send(Cargo::AddRoom(Room::new(rect.into())));
+                self.unfinished_rect = None;
             }
-
-            server.send(Cargo::AddRoom(Room::new(
-                Rect::bounding_rect(pos1, pos2).into(),
-            )));
-            self.unfinished_rect = None;
         }
     }
 
diff --git a/src/math/rect.rs b/src/math/rect.rs
index a8326bc..288c19d 100644
--- a/src/math/rect.rs
+++ b/src/math/rect.rs
@@ -3,6 +3,7 @@
 use super::{ExactSurface, LineSegment, Polygon, Vec2};
 //use alga::general::{Additive, Identity};
 use nalgebra::{RealField, Scalar};
+use num_traits::sign::{self, Signed};
 use num_traits::{NumCast, ToPrimitive, Zero};
 use serde::{Deserialize, Serialize};
 use std::ops::{Add, AddAssign, Sub};
@@ -147,6 +148,14 @@ impl<T: Scalar + Copy> Rect<T> {
             Vec2::new(T::zero(), move_y)
         }
     }
+
+    /// Calculate the area of the rectangle.
+    pub fn area(&self) -> T
+    where
+        T: Signed,
+    {
+        sign::abs(self.w) * sign::abs(self.h)
+    }
 }
 
 impl<T: Scalar + Copy> ExactSurface<T> for Rect<T>
-- 
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