Sprite visibility (#80)

* Expose sprite visibility

* expose context clearing in graphics intf

* Add sprite visibility example to hello_world

Crank.toml

@@ -1,6 +1,10 @@
 [[target]]
     name = "hello_world"
 
+    assets = [
+        "examples/assets/heart.png",
+    ]
+
     [target.metadata]
     name = "Hello World"
     version = "0.1.0"

examples/hello_world.rs

@@ -2,6 +2,9 @@
 
 extern crate alloc;
 
+use crankstart::log_to_console;
+use crankstart::sprite::{Sprite, SpriteManager};
+use crankstart_sys::{LCDBitmapFlip, PDButtons};
 use {
     alloc::boxed::Box,
     anyhow::Error,
@@ -19,21 +22,37 @@ use {
 struct State {
     location: ScreenPoint,
     velocity: ScreenVector,
+    sprite: Sprite,
+}
+
+fn load_sprite() -> Result<Sprite, Error> {
+    let sprite_manager = SpriteManager::get_mut();
+    let mut sprite = sprite_manager.new_sprite()?;
+    let image = Graphics::get().load_bitmap("examples/assets/heart")?;
+    sprite.set_image(image, LCDBitmapFlip::kBitmapUnflipped)?;
+    sprite.move_to(200.0, 120.0)?;
+    sprite.set_z_index(10)?;
+    sprite.set_opaque(false)?;
+    sprite_manager.add_sprite(&sprite)?;
+    Ok(sprite)
 }
 
 impl State {
     pub fn new(_playdate: &Playdate) -> Result<Box<Self>, Error> {
         crankstart::display::Display::get().set_refresh_rate(20.0)?;
+        let sprite = load_sprite()?;
         Ok(Box::new(Self {
             location: point2(INITIAL_X, INITIAL_Y),
             velocity: vec2(1, 2),
+            sprite,
         }))
     }
 }
 
 impl Game for State {
     fn update(&mut self, _playdate: &mut Playdate) -> Result<(), Error> {
         let graphics = Graphics::get();
+        graphics.clear_context()?;
         graphics.clear(LCDColor::Solid(LCDSolidColor::kColorWhite))?;
         graphics.draw_text("Hello World Rust", self.location)?;
 
@@ -47,10 +66,27 @@ impl Game for State {
             self.velocity.y = -self.velocity.y;
         }
 
+        let (_, pushed, _) = System::get().get_button_state()?;
+        if (pushed & PDButtons::kButtonA).0 != 0 {
+            log_to_console!("Button A pushed");
+            self.sprite
+                .set_visible(!self.sprite.is_visible().unwrap_or(false))
+                .unwrap();
+        }
+
         System::get().draw_fps(0, 0)?;
 
         Ok(())
     }
+
+    fn update_sprite(
+        &mut self,
+        sprite: &mut Sprite,
+        _playdate: &mut Playdate,
+    ) -> Result<(), Error> {
+        sprite.mark_dirty()?;
+        Ok(())
+    }
 }
 
 const INITIAL_X: i32 = (400 - TEXT_WIDTH) / 2;

src/graphics.rs

@@ -500,6 +500,11 @@ impl Graphics {
         pd_func_caller!((*self.0).pushContext, raw_bitmap)
     }
 
+    /// Clear the context stack for graphics to make all drawing go to the display framebuffer.
+    pub fn clear_context(&self) -> Result<(), Error> {
+        pd_func_caller!((*self.0).pushContext, core::ptr::null_mut())
+    }
+
     /// Internal function; use `with_context`.
     fn pop_context(&self) -> Result<(), Error> {
         pd_func_caller!((*self.0).popContext)

src/sprite.rs

@@ -239,6 +239,27 @@ impl SpriteInner {
         pd_func_caller!((*self.playdate_sprite).getTag, self.raw_sprite)
     }
 
+    pub fn set_visible(&mut self, visible: bool) -> Result<(), Error> {
+        pd_func_caller!(
+            (*self.playdate_sprite).setVisible,
+            self.raw_sprite,
+            visible as i32
+        )
+    }
+
+    pub fn is_visible(&self) -> Result<bool, Error> {
+        let visible = pd_func_caller!((*self.playdate_sprite).isVisible, self.raw_sprite)?;
+        Ok(visible != 0)
+    }
+
+    pub fn set_opaque(&self, opaque: bool) -> Result<(), Error> {
+        pd_func_caller!(
+            (*self.playdate_sprite).setOpaque,
+            self.raw_sprite,
+            opaque as i32
+        )
+    }
+
     pub fn move_to(&mut self, x: f32, y: f32) -> Result<(), Error> {
         pd_func_caller!((*self.playdate_sprite).moveTo, self.raw_sprite, x, y)
     }
@@ -423,6 +444,24 @@ impl Sprite {
             .move_to(x, y)
     }
 
+    pub fn set_visible(&mut self, visible: bool) -> Result<(), Error> {
+        self.inner
+            .try_borrow_mut()
+            .map_err(Error::msg)?
+            .set_visible(visible)
+    }
+
+    pub fn is_visible(&self) -> Result<bool, Error> {
+        self.inner.try_borrow().map_err(Error::msg)?.is_visible()
+    }
+
+    pub fn set_opaque(&self, opaque: bool) -> Result<(), Error> {
+        self.inner
+            .try_borrow_mut()
+            .map_err(Error::msg)?
+            .set_opaque(opaque)
+    }
+
     pub fn get_position(&self) -> Result<(f32, f32), Error> {
         self.inner.try_borrow().map_err(Error::msg)?.get_position()
     }