Add a way to specify padding/ margins between sprites in a TextureAtl…

…as. (bevyengine#460)

Add a way to specify padding between sprites in a TextureAtlas

crates/bevy_sprite/src/texture_atlas.rs

@@ -63,29 +63,56 @@ impl TextureAtlas {
     }
 
     /// Generate a `TextureAtlas` by splitting a texture into a grid where each
-    /// cell of the grid is one of the textures in the atlas
+    /// cell of the grid  of `tile_size` is one of the textures in the atlas
     pub fn from_grid(
         texture: Handle<Texture>,
-        size: Vec2,
+        tile_size: Vec2,
         columns: usize,
         rows: usize,
     ) -> TextureAtlas {
-        let texture_width = size.x() / columns as f32;
-        let texture_height = size.y() / rows as f32;
+        Self::from_grid_with_padding(texture, tile_size, columns, rows, Vec2::new(0f32, 0f32))
+    }
+
+    /// Generate a `TextureAtlas` by splitting a texture into a grid where each
+    /// cell of the grid of `tile_size` is one of the textures in the atlas and is separated by
+    /// some `padding` in the texture
+    pub fn from_grid_with_padding(
+        texture: Handle<Texture>,
+        tile_size: Vec2,
+        columns: usize,
+        rows: usize,
+        padding: Vec2,
+    ) -> TextureAtlas {
         let mut sprites = Vec::new();
+        let mut x_padding = 0.0;
+        let mut y_padding = 0.0;
+
         for y in 0..rows {
+            if y > 0 {
+                y_padding = padding.y();
+            }
             for x in 0..columns {
+                if x > 0 {
+                    x_padding = padding.x();
+                }
+
+                let rect_min = Vec2::new(
+                    (tile_size.x() + x_padding) * x as f32,
+                    (tile_size.y() + y_padding) * y as f32,
+                );
+
                 sprites.push(Rect {
-                    min: Vec2::new(x as f32 * texture_width, y as f32 * texture_height),
-                    max: Vec2::new(
-                        (x + 1) as f32 * texture_width,
-                        (y + 1) as f32 * texture_height,
-                    ),
+                    min: rect_min,
+                    max: Vec2::new(rect_min.x() + tile_size.x(), rect_min.y() + tile_size.y()),
                 })
             }
         }
+
         TextureAtlas {
-            size,
+            size: Vec2::new(
+                ((tile_size.x() + x_padding) * columns as f32) - x_padding,
+                ((tile_size.y() + y_padding) * rows as f32) - y_padding,
+            ),
             textures: sprites,
             texture,
             texture_handles: None,

examples/2d/sprite_sheet.rs

@@ -32,8 +32,8 @@ fn setup(
             "assets/textures/rpg/chars/gabe/gabe-idle-run.png",
         )
         .unwrap();
-    let texture = textures.get(&texture_handle).unwrap();
-    let texture_atlas = TextureAtlas::from_grid(texture_handle, texture.size, 7, 1);
+
+    let texture_atlas = TextureAtlas::from_grid(texture_handle, Vec2::new(24.0, 24.0), 7, 1);
     let texture_atlas_handle = texture_atlases.add(texture_atlas);
     commands
         .spawn(Camera2dComponents::default())