1 files changed, 79 insertions, 0 deletions
diff --git a/src/snapping.rs b/src/snapping.rs
new file mode 100644
index 0000000..325b62e
--- /dev/null
+++ b/src/snapping.rs
@@ -0,0 +1,79 @@
+//! Responsible for snapping a position with a granularity
+//!
+//! Most of us are not capable of adjusting everything with sub-pixel accuracy. For us filthy casuals,
+//! Snapping was invented. However I hate programs where there is only one option for granularity, so
+//! I thought it should be changeable. This module is responsible for snapping and managing the user
+//! instructions telling the program what granularity should currently be used, if any.
+
+use crate::gui::DecimalNumBox;
+use crate::math::{self, Vec2};
+use raylib::drawing::RaylibDrawHandle;
+use raylib::ffi::KeyboardKey;
+use raylib::RaylibHandle;
+
+/// The struct containing the current snapping information of the program.
+pub struct Snapper {
+    grain: f64,
+    grain_gui: DecimalNumBox<f64>,
+}
+
+impl Snapper {
+    /// Create a new snapper with the default granularity.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Update the grain according to the input the program receives.
+    pub fn update(&mut self, rl: &mut RaylibHandle) {
+        if !self.grain_gui.active() && rl.is_key_pressed(KeyboardKey::KEY_G) {
+            self.grain_gui.set_active(true);
+        }
+
+        if !self.grain_gui.active() {
+            return;
+        }
+
+        self.grain_gui.update(rl);
+
+        if rl.is_key_pressed(KeyboardKey::KEY_ENTER) {
+            self.grain_gui.set_active(false);
+            self.grain = self.grain_gui.value();
+            self.grain_gui.set_value(self.grain);
+        } else if rl.is_key_pressed(KeyboardKey::KEY_ESCAPE) {
+            self.grain_gui.set_active(false);
+            self.grain_gui.set_value(self.grain);
+        }
+    }
+
+    /// Draw the snapper gui
+    pub fn draw(&self, rld: &mut RaylibDrawHandle) {
+        self.grain_gui.draw(
+            rld,
+            "m",
+            &Vec2::new(15., (rld.get_screen_height() - 25) as f64),
+        );
+    }
+
+    /// Get the current granularity of the world snapping in meters. Snapping always starts at (0, 0)
+    pub fn grain(&self) -> f64 {
+        self.grain
+    }
+
+    /// Snap a vector to the grid with the factor being the sub-grid accuracy. For instance, 0.5 will
+    /// snap to half a grid cell, while 2.0 would snap to every second grid cell.
+    pub fn snap(&self, pos: Vec2<f64>) -> Vec2<f64> {
+        Vec2::new(
+            math::round(pos.x, self.grain),
+            math::round(pos.y, self.grain),
+        )
+    }
+}
+
+impl Default for Snapper {
+    fn default() -> Self {
+        Self {
+            grain: 0.5,
+            grain_gui: DecimalNumBox::new(0.5),
+        }
+    }
+}