From 53d376eaeef991850d35318b147f75c8f103319d Mon Sep 17 00:00:00 2001
From: Arne Dußin
Date: Sun, 27 Dec 2020 21:54:31 +0100
Subject: Change to polygongraph instead of polygon in roomtool

The polygon room tool used a convoluted process for determining what the
user actually wants to draw. I have changed to the polygon graph
instead, which makes the checks easier and restricts the user a bit
less. In the process however I found a serious problem with my handling
float, so everything needed to change to margin compares (which I of
course should have done in the beginning. Guys, take the warning
seriously and don't ignore it for ten years like I did. It will come
back to haunt you.. apparently) instead of direct equality.
---
 src/math/surface.rs | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 52 insertions(+), 3 deletions(-)

(limited to 'src/math/surface.rs')

diff --git a/src/math/surface.rs b/src/math/surface.rs
index ab1c703..088ac47 100644
--- a/src/math/surface.rs
+++ b/src/math/surface.rs
@@ -1,10 +1,34 @@
 //! Surfaces, which are areas at a certain position in a vector space.
 
 use super::{LineSegment, Polygon, Rect, Vec2};
-use nalgebra::Scalar;
+use float_cmp::ApproxEq;
+use nalgebra::RealField;
 
-/// Trait that describes an area in the vector space on the field of T
-pub trait Surface<T: Scalar + Copy> {
+/// Trait that describes an area in the vector space on the field of T, with T unable to be
+/// used without rounding.
+pub trait Surface<T: RealField, M>
+where
+    T: ApproxEq<Margin = M>,
+{
+    /// Checks if a point lies on this surface.
+    fn contains_point(&self, point: &Vec2<T>, margin: M) -> bool;
+
+    /// Checks if a line segment is entirely contained by this surface.
+    fn contains_line_segment(&self, line_segment: &LineSegment<T>, margin: M) -> bool;
+
+    /// Checks if a rectangle is entirely contained inside this surface.
+    fn contains_rect(&self, rect: &Rect<T>, margin: M) -> bool;
+
+    /// Checks if a polygon is contained wholly by this surface.
+    fn contains_polygon(&self, polygon: &Polygon<T>, margin: M) -> bool;
+
+    /// Checks if this surface is contained by the rect in it's entirety. Think of it as the reverse
+    /// operation for contains_... on a rectangle.
+    fn is_inside_rect(&self, rect: &Rect<T>) -> bool;
+}
+
+/// The same as Surface, but the vector space will be assumed to be perfectly divideable or checkable.
+pub trait ExactSurface<T: RealField> {
     /// Checks if a point lies on this surface.
     fn contains_point(&self, point: &Vec2<T>) -> bool;
 
@@ -21,3 +45,28 @@ pub trait Surface<T: Scalar + Copy> {
     /// operation for contains_... on a rectangle.
     fn is_inside_rect(&self, rect: &Rect<T>) -> bool;
 }
+
+/*
+// Every exact surface must also be an approximate surface, with margin 0 to be exact.
+impl<T, S> Surface<T> for S where S: ExactSurface<T> {
+    fn contains_point<M>(&self, point: &Vec2<T>, _margin: M) -> bool {
+        ExactSurface::contains_point(&self, point)
+    }
+
+    fn contains_line_segment<M>(&self, line_segment: &LineSegment<T>, margin: M) -> bool {
+        ExactSurface::contains_line_segment(&self, line_segment)
+    }
+
+    fn contains_rect<M>(&self, rect: &Rect<T>, margin: M) -> bool {
+        ExactSurface::contains_rect(&self, rect)
+    }
+
+    fn contains_polygon<M>(&self, polygon: &Polygon<T>, margin: M) -> bool {
+        ExactSurface::contains_polygon(&self, polygon)
+    }
+
+    fn is_inside_rect(&self, rect: &Rect<T>) -> bool {
+        ExactSurface::is_inside_rect(&self, rect)
+    }
+}
+*/
-- 
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