1 files changed, 56 insertions, 0 deletions
diff --git a/src/client/grid.rs b/src/client/grid.rs
new file mode 100644
index 0000000..17d537d
--- /dev/null
+++ b/src/client/grid.rs
@@ -0,0 +1,56 @@
+//! The grid used to divide the map into evenly sized chunks.
+
+use crate::client::colours::DEFAULT_COLOURS;
+use crate::client::transform::Transform;
+use crate::math;
+use raylib::drawing::RaylibDraw;
+
+/// Draw an infinite grid that can be moved around on the screen and zoomed in and out of.
+pub fn draw_grid<D>(rld: &mut D, screen_width: i32, screen_height: i32, transform: &Transform)
+where
+    D: RaylibDraw,
+{
+    /* Calculate the first whole meter that can be seen on the grid. This is the first meter that
+     * will be seen on screen.
+     */
+    let mut first_cell = *transform.translation_px() / -transform.pixels_per_m();
+    first_cell.x = first_cell.x.floor();
+    first_cell.y = first_cell.y.floor();
+
+    let mut cell = first_cell;
+    let mut draw_y = transform.point_m_to_px(&cell).y;
+    loop {
+        draw_y = math::round(draw_y, 1.);
+        rld.draw_line(
+            0,
+            draw_y as i32,
+            screen_width,
+            draw_y as i32,
+            DEFAULT_COLOURS.grid_lines,
+        );
+        cell.y += 1.;
+        draw_y = transform.point_m_to_px(&cell).y;
+
+        if draw_y as i32 > screen_height {
+            break;
+        }
+    }
+
+    let mut draw_x = transform.point_m_to_px(&cell).x;
+    loop {
+        draw_x = math::round(draw_x, 1.);
+        rld.draw_line(
+            draw_x as i32,
+            0,
+            draw_x as i32,
+            screen_height,
+            DEFAULT_COLOURS.grid_lines,
+        );
+        cell.x += 1.;
+        draw_x = transform.point_m_to_px(&cell).x;
+
+        if draw_x as i32 > screen_width {
+            break;
+        }
+    }
+}