Print the CPU usage for the stereo sound example

agb/examples/stereo_sound.rs

@@ -1,16 +1,41 @@
 #![no_std]
 #![no_main]
 
-use agb::sound::mixer::SoundChannel;
-use agb::{include_wav, Gba};
+use agb::{
+    display::{
+        tiled::{RegularBackgroundSize, RegularMap, TileSetting, VRamManager},
+        Font, Priority,
+    },
+    include_font, include_wav,
+    sound::mixer::SoundChannel,
+    Gba,
+};
+
+use core::fmt::Write;
 
 // Music - "Let it in" by Josh Woodward, free download at http://joshwoodward.com
 const LET_IT_IN: &[u8] = include_wav!("examples/JoshWoodward-LetItIn.wav");
 
+const FONT: Font = include_font!("examples/font/yoster.ttf", 12);
+
 #[agb::entry]
 fn main(mut gba: Gba) -> ! {
     let vblank_provider = agb::interrupt::VBlank::get();
 
+    let (gfx, mut vram) = gba.display.video.tiled0();
+    let mut bg = gfx.background(Priority::P0, RegularBackgroundSize::Background32x32);
+
+    init_background(&mut bg, &mut vram);
+
+    let mut writer = FONT.render_text((0u16, 3u16).into(), 1, 0, &mut bg, &mut vram);
+
+    writeln!(&mut writer, "Let it in by Josh Woodward").unwrap();
+
+    writer.commit();
+
+    bg.commit(&mut vram);
+    bg.show();
+
     let timer_controller = gba.timers.timers();
     let mut timer = timer_controller.timer2;
     timer.set_enabled(true);
@@ -23,8 +48,11 @@ fn main(mut gba: Gba) -> ! {
     mixer.play_sound(channel).unwrap();
 
     let mut frame_counter = 0i32;
+    let mut has_written_frame_time = false;
     loop {
         vblank_provider.wait_for_vblank();
+        bg.commit(&mut vram);
+
         let before_mixing_cycles = timer.value();
         mixer.after_vblank();
         mixer.frame();
@@ -32,15 +60,40 @@ fn main(mut gba: Gba) -> ! {
 
         frame_counter = frame_counter.wrapping_add(1);
 
-        if frame_counter % 128 == 0 {
+        if frame_counter % 128 == 0 && !has_written_frame_time {
             let total_cycles = after_mixing_cycles.wrapping_sub(before_mixing_cycles) as u32;
 
             let percent = (total_cycles * 100) / 280896;
-            agb::println!(
-                "Took {} cycles to calculate mixer ~= {}% of total frame",
-                total_cycles,
-                percent
-            );
+
+            let mut writer = FONT.render_text((0u16, 6u16).into(), 2, 0, &mut bg, &mut vram);
+            writeln!(&mut writer, "{total_cycles} cycles").unwrap();
+            writeln!(&mut writer, "{percent} percent").unwrap();
+
+            writer.commit();
+
+            has_written_frame_time = true;
         }
     }
 }
+
+fn init_background(bg: &mut RegularMap, vram: &mut VRamManager) {
+    let background_tile = vram.new_dynamic_tile().fill_with(0);
+
+    vram.set_background_palette_raw(&[
+        0x0000, 0x0ff0, 0x00ff, 0xf00f, 0xf0f0, 0x0f0f, 0xaaaa, 0x5555, 0x0000, 0x0000, 0x0000,
+        0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+    ]);
+
+    for y in 0..20u16 {
+        for x in 0..30u16 {
+            bg.set_tile(
+                vram,
+                (x, y).into(),
+                &background_tile.tile_set(),
+                TileSetting::from_raw(background_tile.tile_index()),
+            );
+        }
+    }
+
+    vram.remove_dynamic_tile(background_tile);
+}