From 668d2a18d54819d6b16fca2bbb2dabf1838d1372 Mon Sep 17 00:00:00 2001
From: Denis Nutiu <denis.nutiu@gmail.com>
Date: Sun, 24 Nov 2024 21:00:32 +0200
Subject: [PATCH] Add terminal display.rs

---
 Cargo.toml      |  3 +++
 src/display.rs  | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/emulator.rs | 16 ++++++++++------
 src/main.rs     |  4 +++-
 4 files changed, 66 insertions(+), 7 deletions(-)
 create mode 100644 src/display.rs

diff --git a/Cargo.toml b/Cargo.toml
index 0fa5b53..06b0ba7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,6 +3,9 @@ name = "Chip8Emulator"
 version = "0.1.0"
 edition = "2021"
 
+[lints.rust]
+dead_code = "allow"
+
 [dependencies]
 log = "0.4.22"
 env_logger = "0.11.5"
diff --git a/src/display.rs b/src/display.rs
new file mode 100644
index 0000000..9a29593
--- /dev/null
+++ b/src/display.rs
@@ -0,0 +1,50 @@
+
+/// Represents the display's width in pixels.
+const DISPLAY_WIDTH: usize = 64;
+
+/// Represents the display's height pixels.
+const DISPLAY_HEIGHT: usize = 32;
+
+/// Display trait
+pub trait Display {
+    /// Re-draws the display.
+    fn redraw(&self);
+    /// Draws the display.
+    fn draw(&mut self);
+}
+
+/// Display models the Chip8's display.
+pub struct TerminalDisplay {
+    /// Holds the display data, each bit corresponds to a pixel.
+    display_data: [bool; DISPLAY_WIDTH * DISPLAY_HEIGHT],
+}
+
+impl TerminalDisplay {
+    pub fn new() -> TerminalDisplay {
+        TerminalDisplay {
+            display_data: [false; DISPLAY_WIDTH * DISPLAY_HEIGHT]
+        }
+    }
+}
+
+impl Display for TerminalDisplay {
+    /// Re-draws the display.
+    fn redraw(&self) {
+        // ANSI Escape code to move cursor to row 1 column 1
+        // See https://stackoverflow.com/a/4062051
+        print!("{esc}[2J{esc}[1;1H", esc = 27 as char);
+    }
+    /// Draws the display.
+    fn draw(&mut self) {
+        for row in 0..32 {
+            for column in 0..64 {
+                if self.display_data[row * DISPLAY_WIDTH + column] {
+                    print!("█")
+                } else {
+                    print!(" ")
+                }
+            }
+            print!("\n")
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/emulator.rs b/src/emulator.rs
index 17d771a..82c2696 100644
--- a/src/emulator.rs
+++ b/src/emulator.rs
@@ -2,7 +2,8 @@ use anyhow::anyhow;
 use log::{debug, info};
 use std::fs::File;
 use std::io::Read;
-use std::path::Path;
+use std::path::{Path};
+use crate::display::{Display, TerminalDisplay};
 
 const MEMORY_SIZE: usize = 4096;
 const NUMBER_OF_REGISTERS: usize = 16;
@@ -42,15 +43,18 @@ pub struct Emulator {
     sound_timer: u8,
     /// The stack pointer register.
     stack_pointer: u8,
+    /// The display_data holds all the data associated with the display
+    display: Box<dyn Display>
 }
 
 impl Emulator {
     /// Creates a new `Emulator` instance.
     ///
-    pub fn new() -> Emulator {
+    pub fn new(display: Box<dyn Display>) -> Emulator {
         let mut emulator = Emulator {
-            memory: [0; 4096],
-            registers: [0; 16],
+            memory: [0; MEMORY_SIZE],
+            registers: [0; NUMBER_OF_REGISTERS],
+            display,
             index_register: 0,
             program_counter: 0,
             delay_timer: 0,
@@ -113,7 +117,7 @@ mod tests {
 
     #[test]
     fn test_load_font_data() {
-        let emulator = Emulator::new();
+        let emulator = Emulator::new(Box::from(TerminalDisplay::new()));
         assert_eq!(emulator.memory[0xf0..0xf0 + 80], FONT_SPRITES)
     }
 
@@ -126,7 +130,7 @@ mod tests {
             .expect("Failed to read test ROM");
 
         // Test
-        let mut emulator = Emulator::new();
+        let mut emulator = Emulator::new(Box::from(TerminalDisplay::new()));
         emulator
             .load_rom("roms/ibm-logo.ch8")
             .expect("failed to load ROM");
diff --git a/src/main.rs b/src/main.rs
index c40446e..f8288ed 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,12 +1,14 @@
 use crate::emulator::Emulator;
 use env_logger;
+use crate::display::TerminalDisplay;
 
 mod emulator;
+mod display;
 
 fn main() -> Result<(), anyhow::Error> {
     env_logger::init();
 
-    let mut emulator = Emulator::new();
+    let mut emulator = Emulator::new(Box::from(TerminalDisplay::new()));
 
     emulator.emulate(String::from("./roms/ibm-logo.ch8"))?;