fix texture bleeding and object jittering

src/shared_game_state.rs

@@ -22,7 +22,7 @@ use crate::sound::SoundManager;
 use crate::stage::StageData;
 use crate::str;
 use crate::text_script::{ScriptMode, TextScriptExecutionState, TextScriptVM};
-use crate::texture_set::TextureSet;
+use crate::texture_set::{TextureSet, g_mag};
 use crate::touch_controls::TouchControls;
 
 #[derive(PartialEq, Eq, Copy, Clone)]
@@ -169,6 +169,8 @@ impl SharedGameState {
     pub fn new(ctx: &mut Context) -> GameResult<SharedGameState> {
         let screen_size = graphics::drawable_size(ctx);
         let scale = screen_size.1.div(235.0).floor().max(1.0);
+        unsafe { g_mag = scale };
+
         let canvas_size = (screen_size.0 / scale, screen_size.1 / scale);
 
         let mut constants = EngineConstants::defaults();
@@ -344,6 +346,7 @@ impl SharedGameState {
         self.screen_size = graphics::drawable_size(ctx);
         self.scale = self.screen_size.1.div(240.0).floor().max(1.0);
         self.canvas_size = (self.screen_size.0 / self.scale, self.screen_size.1 / self.scale);
+        unsafe { g_mag = self.scale };
 
         graphics::set_screen_coordinates(ctx, graphics::Rect::new(0.0, 0.0, self.screen_size.0, self.screen_size.1))?;
 

src/texture_set.rs

@@ -17,6 +17,8 @@ use crate::engine_constants::EngineConstants;
 use crate::shared_game_state::{Season, Settings};
 use crate::str;
 
+pub static mut g_mag: f32 = 1.0;
+
 pub struct SizedBatch {
     pub batch: SpriteBatch,
     width: usize,
@@ -76,11 +78,16 @@ impl SizedBatch {
         self.add_rect_scaled(x, y, self.scale_x, self.scale_y, rect)
     }
 
-    pub fn add_rect_scaled(&mut self, x: f32, y: f32, scale_x: f32, scale_y: f32, rect: &common::Rect<u16>) {
+    pub fn add_rect_scaled(&mut self, mut x: f32, mut y: f32, scale_x: f32, scale_y: f32, rect: &common::Rect<u16>) {
         if (rect.right - rect.left) == 0 || (rect.bottom - rect.top) == 0 {
             return;
         }
 
+        unsafe {
+            x = (x * g_mag).floor() / g_mag;
+            y = (y * g_mag).floor() / g_mag;
+        }
+
         let param = DrawParam::new()
             .src(Rect::new(rect.left as f32 / self.width as f32,
                            rect.top as f32 / self.height as f32,