rstnode: implement viewport scrolling and zooming

games/rstnode/rst-client/src/graphics/vector2.rs

@@ -1,5 +1,5 @@
 use std::fmt::{self, Display, Formatter};
-use std::ops::{Add, Mul, Sub, SubAssign};
+use std::ops::{Add, AddAssign, Div, Mul, MulAssign, Sub, SubAssign};
 
 /// Just a vector
 #[derive(Debug, Default, Copy, Clone, PartialEq, PartialOrd)]
@@ -27,6 +27,29 @@ impl Vector2 {
     }
 }
 
+
+impl Add for Vector2 {
+    type Output = Vector2;
+
+    fn add(self, o: Vector2) -> Self::Output {
+        Vector2 {
+            x: self.x + o.x,
+            y: self.y + o.y,
+        }
+    }
+}
+
+
+impl AddAssign for Vector2 {
+    fn add_assign(&mut self, o: Self) {
+        *self = Self {
+            x: self.x + o.x,
+            y: self.y + o.y,
+        }
+    }
+}
+
+
 impl Sub for Vector2 {
     type Output = Vector2;
 
@@ -47,22 +70,43 @@ impl SubAssign for Vector2 {
     }
 }
 
-impl Add for Vector2 {
+
+impl Mul for Vector2 {
     type Output = Vector2;
 
-    fn add(self, o: Vector2) -> Self::Output {
+    fn mul(self, o: Vector2) -> Self::Output {
         Vector2 {
-            x: self.x + o.x,
-            y: self.y + o.y,
+            x: self.x * o.x,
+            y: self.y * o.y,
         }
     }
 }
 
-impl Mul for Vector2 {
+impl Div<f32> for Vector2 {
     type Output = Vector2;
 
-    fn mul(self, o: Vector2) -> Self::Output {
+    fn div(self, o: f32) -> Self::Output {
         Vector2 {
+            x: self.x / o,
+            y: self.y / o,
+        }
+    }
+}
+
+impl Mul<f32> for Vector2 {
+    type Output = Vector2;
+
+    fn mul(self, o: f32) -> Self::Output {
+        Self {
+            x: self.x * o,
+            y: self.y * o,
+        }
+    }
+}
+
+impl MulAssign for Vector2 {
+    fn mul_assign(&mut self, o: Self) {
+        *self = Self {
             x: self.x * o.x,
             y: self.y * o.y,
         }

games/rstnode/rst-client/src/input.rs

@@ -18,6 +18,8 @@ pub struct InputHandle {
     pub right_pressed: bool,
     /// Set when pressing left mouse and unset when releasing it
     pub drag_point: Option<Vector2>,
+    /// Get the scroll-wheel position this frame
+    pub scroll_offset: f32,
 }
 
 impl InputHandle {
@@ -28,6 +30,7 @@ impl InputHandle {
             middle_pressed: false,
             right_pressed: false,
             drag_point: None,
+            scroll_offset: 1.0,
         }
     }
 
@@ -55,6 +58,11 @@ impl EventHandler for InputHandle {
 
         Ok(())
     }
+
+    fn mouse_wheel_event(&mut self, _ctx: &mut Context, _: f32, y: f32) {
+        self.scroll_offset += y * 0.1;
+    }
+
     fn draw(&mut self, _: &mut Context) -> GameResult<()> {
         panic!("Don't draw the input handle!");
     }

games/rstnode/rst-client/src/state.rs

@@ -55,7 +55,7 @@ impl ClientState {
     pub fn viewport(&mut self) -> &mut Viewport {
         &mut self.vp
     }
-    
+
     pub fn assets(&self) -> &Assets {
         &self.assets
     }
@@ -76,6 +76,13 @@ impl EventHandler for ClientState {
         Ok(())
     }
 
+    fn mouse_wheel_event(&mut self, ctx: &mut Context, x: f32, y: f32) {
+        self.input.mouse_wheel_event(ctx, x, y);
+        let zoom = self.input.scroll_offset;
+        self.viewport().zoom(zoom);
+            
+    }
+
     fn draw(&mut self, ctx: &mut Context) -> GameResult<()> {
         graphics::clear(ctx, graphics::Color::from_rgb(15, 15, 15));
 

games/rstnode/rst-client/src/viewport.rs

@@ -12,6 +12,7 @@ pub struct Viewport {
     start: Vector2,
     prev_start: Vector2,
     size: Vector2,
+    orig_size: Vector2,
 }
 
 impl Viewport {
@@ -19,10 +20,6 @@ impl Viewport {
         Self::default()
     }
 
-    pub fn start(&self) -> &Vector2 {
-        &self.start
-    }
-
     /// Must be called at least once before calling
     /// [`update`](Self::update)
     pub fn init(&mut self, ctx: &mut Context) {
@@ -30,6 +27,7 @@ impl Viewport {
         self.start = Vector2::new(x, y);
         self.prev_start = self.start;
         self.size = Vector2::new(w, h);
+        self.orig_size = self.size;
     }
 
     /// Update the game state with the curent viewport data
@@ -49,15 +47,25 @@ impl Viewport {
 
     /// Apply changes from the input handle to the viewport
     pub fn apply(&mut self, _: &mut Context, input: &InputHandle) -> GameResult<()> {
+
+        // Move the viewport around
         if input.middle_pressed {
             let drag = input.drag_point.as_ref().unwrap().clone();
             let pos = input.mouse_pos.clone();
             self.start = self.prev_start + (drag - pos);
-            debug!("Changing VP start: {}", self.start);
         } else {
             self.prev_start = self.start;
         }
 
+        // Compute the scroll level
         Ok(())
     }
+
+    /// Called when the input handler scroll event is handled
+    pub fn zoom(&mut self, zoom: f32) {
+        let new_size = self.orig_size * zoom;
+        let diff = self.size - new_size;
+        self.start += diff / 2.0;
+        self.size = new_size;
+    }
 }