feat(demo): exercise background and sprite mosaic controls

src/mosaic_demo.rs

@@ -0,0 +1,39 @@
+//! Original tile scene with CPU-controlled background and sprite mosaic sizes.
+
+use crate::{
+    graphics_demo::{GraphicsDemo, GraphicsError},
+    input::Buttons,
+    machine::Machine,
+    memory::MemoryError,
+    video::Framebuffer,
+};
+
+/// Completed updates and nine-bit horizontal/vertical scroll, as three words.
+pub const MOSAIC_STATE: u32 = crate::tile_demo::TILE_STATE;
+
+pub struct MosaicDemo {
+    runner: GraphicsDemo,
+}
+
+impl MosaicDemo {
+    pub fn new() -> Result<Self, MemoryError> {
+        Ok(Self {
+            runner: GraphicsDemo::with_program(crate::tile_demo::mosaic_program())?,
+        })
+    }
+
+    pub fn machine(&self) -> &Machine {
+        self.runner.machine()
+    }
+
+    /// Block dimensions cycle from 1 to 16 pixels, changing every eight updates.
+    /// Z bypasses BG mosaic; X bypasses OBJ mosaic. Q/W rotate/zoom the sprite.
+    /// Arrows scroll; Enter resets scrolling. The host only supplies input.
+    pub fn frame(
+        &mut self,
+        buttons: Buttons,
+        output: &mut Framebuffer,
+    ) -> Result<usize, GraphicsError> {
+        self.runner.frame_with_control(buttons, output, 0x1340)
+    }
+}