WIP: Wall intersection

diff --git a/src/common/geometry.rs b/src/common/geometry.rs
index 5a03ffb..455e600 100644 (file)
--- a/src/common/geometry.rs
+++ b/src/common/geometry.rs
@@ -1,5 +1,7 @@
 use std::ops::{Add, AddAssign, Sub, SubAssign, Mul, MulAssign, Div, DivAssign, Neg};
 
+////////// POINT ///////////////////////////////////////////////////////////////
+
 #[macro_export]
 macro_rules! point {
     ( $x:expr, $y:expr ) => {
@@ -181,6 +183,36 @@ impl Radians {
     }
 }
 
+////////// INTERSECTION ////////////////////////////////////////////////////////
+
+#[derive(Debug)]
+pub enum Intersection {
+    Point(Point<f64>),
+    //Line(Point<f64>, Point<f64>), // TODO: overlapping collinear
+    None,
+}
+
+impl Intersection {
+    pub fn lines(p1: Point<f64>, p2: Point<f64>, p3: Point<f64>, p4: Point<f64>) -> Intersection {
+       let s1 = p2 - p1;
+       let s2 = p4 - p3;
+
+       let denomimator = -s2.x * s1.y + s1.x * s2.y;
+       if denomimator != 0.0 {
+           let s = (-s1.y * (p1.x - p3.x) + s1.x * (p1.y - p3.y)) / denomimator;
+           let t = ( s2.x * (p1.y - p3.y) - s2.y * (p1.x - p3.x)) / denomimator;
+
+           if s >= 0.0 && s <= 1.0 && t >= 0.0 && t <= 1.0 {
+               return Intersection::Point(p1 + (s1 * t))
+           }
+       }
+
+       Intersection::None
+    }
+}
+
+////////// DIMENSION ///////////////////////////////////////////////////////////
+
 #[macro_export]
 macro_rules! dimen {
     ( $w:expr, $h:expr ) => {
@@ -210,16 +242,7 @@ impl<T> From<(T, T)> for Dimension<T> {
     }
 }
 
-#[macro_export]
-macro_rules! hashmap {
-    ($($k:expr => $v:expr),*) => {
-       {
-           let mut map = std::collections::HashMap::new();
-           $(map.insert($k, $v);)*
-           map
-       }
-    }
-}
+////////// TESTS ///////////////////////////////////////////////////////////////
 
 #[cfg(test)]
 mod tests {
@@ -296,4 +319,18 @@ mod tests {
         assert_eq!(r.area(), 30 * 20);
         // let a = Dimension::from(("a".to_string(), "b".to_string())).area(); // this doesn't work, because area() is not implemented for String
     }
+
+    #[test]
+    fn intersection_of_lines() {
+        let p1 = point!(0.0, 0.0);
+        let p2 = point!(2.0, 2.0);
+        let p3 = point!(0.0, 2.0);
+        let p4 = point!(2.0, 0.0);
+       let r = Intersection::lines(p1, p2, p3, p4);
+       if let Intersection::Point(p) = r {
+            assert_eq!(p, point!(1.0, 1.0));
+       } else {
+           panic!();
+       }
+    }
 }

diff --git a/src/common/mod.rs b/src/common/mod.rs
index 9c39453..505860d 100644 (file)
--- a/src/common/mod.rs
+++ b/src/common/mod.rs
@@ -1,8 +1,22 @@
 mod geometry;
-pub use common::geometry::Point;
-pub use common::geometry::Dimension;
-pub use common::geometry::Radians;
-pub use common::geometry::Degrees;
+pub use common::geometry::{
+    Point,
+    Dimension,
+    Radians,
+    Degrees,
+    Intersection,
+};
 
 mod time;
 pub use common::time::ScopeTimer;
+
+#[macro_export]
+macro_rules! hashmap {
+    ($($k:expr => $v:expr),*) => {
+       {
+           let mut map = std::collections::HashMap::new();
+           $(map.insert($k, $v);)*
+           map
+       }
+    }
+}

diff --git a/src/core/game.rs b/src/core/game.rs
index 554bde7..386057b 100644 (file)
--- a/src/core/game.rs
+++ b/src/core/game.rs
@@ -4,7 +4,7 @@ use common::{Point, Radians};
 use core::app::StateChange;
 use core::controller::Controller;
 use core::controller::ControllerManager;
-use core::level::{Level, LevelGenerator};
+use core::level::{Level, LevelGenerator, Wall, IntersectResult::Intersection};
 use core::render::Renderer;
 use point;
 use sdl2::event::Event;
@@ -271,12 +271,11 @@ impl Object for Boll {
        self.vel += lvl.gravity;
        self.pos += self.vel;
 
-       let x = (self.pos.x / lvl.grid.cell_size.width as f64).min(lvl.grid.size.width as f64 - 1.0).max(0.0) as usize;
-       let y = (self.pos.y / lvl.grid.cell_size.height as f64).min(lvl.grid.size.height as f64 - 1.0).max(0.0) as usize;
-       if lvl.grid.cells[x][y] {
+       if let Intersection(wall, pos) = lvl.intersect_walls(self.pos - self.vel, self.pos) {
            if self.bounces == 0 {
                return Dead
            }
+           self.pos = pos;
            self.vel *= -0.25;
            self.pos += self.vel;
            self.bounces -= 1;
@@ -288,6 +287,23 @@ impl Object for Boll {
                ..*self
            }));
        }
+       // let x = (self.pos.x / lvl.grid.cell_size.width as f64).min(lvl.grid.size.width as f64 - 1.0).max(0.0) as usize;
+       // let y = (self.pos.y / lvl.grid.cell_size.height as f64).min(lvl.grid.size.height as f64 - 1.0).max(0.0) as usize;
+       // if lvl.grid.cells[x][y] {
+       //     if self.bounces == 0 {
+       //      return Dead
+       //     }
+       //     self.vel *= -0.25;
+       //     self.pos += self.vel;
+       //     self.bounces -= 1;
+       //     use rand::distributions::{Distribution, Normal};
+       //     let mut rng = rand::thread_rng();
+       //     let a = Radians(self.vel.to_radians().0 + Normal::new(0.0, 0.75).sample(&mut rng));
+       //     objects.push(Box::new(Boll {
+       //      vel: Point::from(a) * Normal::new(1.0, 0.25).sample(&mut rng) * self.vel.length(),
+       //      ..*self
+       //     }));
+       // }
 
        Alive
     }

diff --git a/src/core/level/mod.rs b/src/core/level/mod.rs
index 3945776..2a90739 100644 (file)
--- a/src/core/level/mod.rs
+++ b/src/core/level/mod.rs
@@ -1,4 +1,4 @@
-use common::{Point, Dimension};
+use common::{Point, Dimension, Intersection};
 use core::render::Renderer;
 use sprites::SpriteManager;
 use std::rc::Rc;
@@ -96,6 +96,26 @@ impl Level {
            }
        }
     }
+
+    pub fn intersect_walls(&self, p1: Point<f64>, p2: Point<f64>) -> IntersectResult {
+       let c = point!(p2.x as isize / self.wall_grid.cell_size.width as isize, p2.y as isize / self.wall_grid.cell_size.height as isize);
+       if let Some(walls) = self.wall_grid.at(c) {
+           for w in walls {
+               if let Intersection::Point(p) = Intersection::lines(p1, p2, w.p1, w.p2) {
+                   let wall = Wall {
+                       edge: Rc::clone(&w),
+                   };
+                   return IntersectResult::Intersection(wall, p)
+               }
+           }
+       }
+       IntersectResult::None
+    }
+}
+
+pub enum IntersectResult {
+    Intersection(Wall, Point<f64>),
+    None
 }
 
 ////////// GRID ////////////////////////////////////////////////////////////////
@@ -107,6 +127,19 @@ pub struct Grid<T> {
     pub cells: Vec<Vec<T>>,
 }
 
+impl<T> Grid<T> {
+    pub fn at<C>(&self, c: C) -> Option<&T>
+    where C: Into<(isize, isize)>
+    {
+       let c = c.into();
+       if c.0 >= 0 && c.0 < self.size.width as isize && c.1 >= 0 && c.1 < self.size.height as isize {
+           Some(&self.cells[c.0 as usize][c.1 as usize])
+       } else {
+           None
+       }
+    }
+}
+
 ////////// WALL REGION /////////////////////////////////////////////////////////
 
 #[derive(Debug)]
@@ -116,7 +149,7 @@ pub struct WallRegion {
 
 impl WallRegion {
     pub fn new(points: Vec<Point<f64>>) -> Rc<Self> {
-       let mut edges = vec!();
+       let mut edges = Vec::with_capacity(points.len());
 
        for i in 0..points.len() {
            let edge = Rc::new(WallEdge {
@@ -151,3 +184,10 @@ struct WallEdge {
     pub p1: Point<f64>,
     pub p2: Point<f64>,
 }
+
+////////// WALL ////////////////////////////////////////////////////////////////
+
+pub struct Wall {
+//    region: Rc<WallRegion>,
+    edge: Rc<WallEdge>,
+}