Day 10, puzzle 2

src/bin/d10p2.rs

@@ -0,0 +1,14 @@
+use aoc22::{day10, util};
+
+pub fn main() {
+    let instructions = day10::parse_instructions(&util::parse_input());
+    let mut cpu = day10::CPU::new(instructions);
+    let mut crt = day10::CRT::new();
+
+    for _ in 0..240 {
+        crt.render(&cpu);
+        cpu.do_cycle().expect("No more instructions?");
+    }
+
+    crt.draw();
+}

src/day10.rs

@@ -1,7 +1,7 @@
 #[derive(Debug)]
 pub enum Instruction {
     Noop,
-    Addx(i32),
+    Addx(isize),
 }
 
 pub fn parse_instructions(input: &String) -> Vec<Instruction> {
@@ -21,8 +21,9 @@ pub fn parse_instructions(input: &String) -> Vec<Instruction> {
     result
 }
 
+#[derive(Debug)]
 pub struct CPU {
-    pub x: i32,
+    pub x: isize,
     pub cycle: isize,
     instructions: Vec<Instruction>,
     pc: usize,
@@ -63,6 +64,41 @@ impl CPU {
     }
 
     pub fn signal_strength(&self) -> isize {
-        return (self.x as isize) * (self.cycle + 1);
+        return self.x * (self.cycle + 1);
+    }
+}
+
+pub struct CRT {
+    pub pixels: [[char; 40]; 6],
+}
+
+impl CRT {
+    pub fn new() -> CRT {
+        CRT {
+            pixels: [['.'; 40]; 6],
+        }
+    }
+
+    pub fn render(&mut self, cpu: &CPU) {
+        let c = cpu.cycle;
+        assert!(c >= 0 && c < 240);
+        let x = c % 40;
+        let y = c / 40;
+        let sprite_pos = cpu.x - 1;
+        let px = &mut self.pixels[y as usize][x as usize];
+        if x >= sprite_pos && x < sprite_pos + 3 {
+            *px = '#';
+        } else {
+            *px = '.';
+        }
+    }
+
+    pub fn draw(&self) {
+        for y in 0..6 {
+            for x in 0..40 {
+                print!("{}", self.pixels[y][x]);
+            }
+            print!("\n");
+        }
     }
 }