Make zoom-levels whole numbers to combat round-err

The grid was offset at certain zoom-levels and lower positions, so for
now I just made only whole zoom-levels possible, which removes the
offset. However, I consider this a band-aid-solution. Maybe change from
f32 to f64 and try out if that fixes it? Otherwise, a different
algorithm might work.

2 files changed, 28 insertions, 2 deletions

diff --git a/src/grid.rs b/src/grid.rs
index 1ec49a3..d5fac6d 100644
--- a/src/grid.rs
+++ b/src/grid.rs
@@ -22,13 +22,34 @@ where
     let translation_y_px: i32 =
         transform.translation_px().y as i32 % transform.pixels_per_m() as i32;
 
+    /*
+    let mut row = 0;
+    loop {
+        let line_y = translation_y_px + (transform.pixels_per_m() * row as f32) as i32;
+        if line_y > screen_height {
+            break;
+        }
+        rld.draw_line(0, line_y as i32, screen_width, line_y as i32, LINE_COLOUR);
+        row += 1;
+    }
+
+    let mut column = 0;
+    loop {
+        let line_x = translation_x_px + (transform.pixels_per_m() * column as f32) as i32;
+        if line_x > screen_width {
+            break;
+        }
+        rld.draw_line(line_x as i32, 0, line_x as i32, screen_height, LINE_COLOUR);
+        column += 1;
+    }
+    */
+
     // Draw the row lines.
     let mut line_y: f32 = translation_y_px as f32;
     while line_y <= screen_height as f32 {
         rld.draw_line(0, line_y as i32, screen_width, line_y as i32, LINE_COLOUR);
         line_y += transform.pixels_per_m();
     }
-
     // Draw the column lines.
     let mut line_x: f32 = translation_x_px as f32;
     while line_x <= screen_width as f32 {
diff --git a/src/transform.rs b/src/transform.rs
index f44888b..ca359f0 100644
--- a/src/transform.rs
+++ b/src/transform.rs
@@ -6,7 +6,7 @@
 use crate::math::{Rect, Vec2};
 
 const STANDARD_PIXELS_PER_M: f32 = 64.;
-const MIN_PIXELS_PER_M: f32 = 0.5;
+const MIN_PIXELS_PER_M: f32 = 5.;
 const MAX_PIXELS_PER_M: f32 = 10_000.;
 
 pub struct Transform {
@@ -82,6 +82,11 @@ impl Transform {
      * pass the standard zoom factor.
      */
     fn normalise_zoom(&mut self) {
+        self.pixels_per_m = self.pixels_per_m as u32 as f32;
+        if self.pixels_per_m < MIN_PIXELS_PER_M {
+            self.pixels_per_m = MIN_PIXELS_PER_M;
+        }
+
         if self.pixels_per_m > STANDARD_PIXELS_PER_M - 5.
             && self.pixels_per_m < STANDARD_PIXELS_PER_M + 5.
         {