1 files changed, 76 insertions, 0 deletions
diff --git a/game_server/src/collide.rs b/game_server/src/collide.rs
new file mode 100644
index 0000000..21ec99c
--- /dev/null
+++ b/game_server/src/collide.rs
@@ -0,0 +1,76 @@
+use crate::maths::{Vec2, AABox, RBox};
+
+pub trait Collide<Rhs> {
+    fn collides(&self, other: &Rhs) -> bool;
+}
+
+impl Collide<Vec2> for Vec2 {
+    fn collides(&self, other: &Self) -> bool {
+        self == other
+    }
+}
+
+impl Collide<Vec2> for AABox {
+    fn collides(&self, other: &Vec2) -> bool {
+        self.pos < *other && other < &(self.pos + self.size) 
+    }
+}
+
+impl Collide<AABox> for AABox {
+    fn collides(&self, other: &Self) -> bool {
+        self.collides(&other.pos)
+        || self.collides(&(other.pos + Vec2{x: other.size.x, y: 0.0}))
+        || self.collides(&(other.pos + Vec2{x: 0.0, y: other.size.y}))
+        || self.collides(&(other.pos + other.size))
+
+        || other.collides(&(self.pos))
+        || other.collides(&(self.pos + Vec2{x: self.size.x, y: 0.0}))
+        || other.collides(&(self.pos + Vec2{x: 0.0, y: self.size.y}))
+        || other.collides(&(self.pos + self.size))
+    }
+}
+
+impl Collide<Vec2> for RBox {
+    fn collides(&self, other: &Vec2) -> bool {
+
+        let da = self.size.norm();
+        let dax = other.x - self.pos.x;
+        let day = other.y - self.pos.y;
+        
+        let dot = dax * da.x + day * da.y;
+        let px = self.pos.x + dx * dot;
+        let py = self.pos.y + da.y * dot;
+       
+        let p = Vec2{x: px, y: py};
+        if !(self.pos < p && p < self.pos + self.size) {
+            return false; 
+        } 
+
+        let ddx = other.x-px; 
+        let ddy = other.y-py;
+        let manhattenDistance = ddx + ddy;
+
+        manhattenDistance < self.w 
+    }
+}
+
+impl Collide<AABox> for RBox {
+    fn collides(&self, other: &Box) -> bool {
+        self.collides(&other.pos)
+        || self.collides(&(other.pos + Vec2{x: other.size.x, y: 0.0}))
+        || self.collides(&(other.pos + Vec2{x: 0.0, y: other.size.y}))
+        || self.collides(&(other.pos + other.size))
+
+        || other.collides(&(self.pos))
+        || other.collides(&(self.pos + Vec2{x: self.size.x, y: 0.0}))
+        || other.collides(&(self.pos + Vec2{x: 0.0, y: self.size.y}))
+        || other.collides(&(self.pos + self.size))
+        
+    }
+}
+
+impl<S, T: Collide<S>> Collide<S> for Vec<T> {
+    fn collides(&self, other: &S) -> bool {
+        self.iter().any(|x| x.collides(other))
+    }
+}