General cleanup and dependency removal

.cargo/config.toml

@@ -1,2 +1,2 @@
-[target.x86_64-pc-windows-msvc]
+[target.'cfg(windows)']
 rustflags = ["-C", "link-arg=/STACK:8388608"]

Cargo.toml

@@ -13,18 +13,19 @@ name = "rbgb"
 path = "src/lib.rs"
 
 [[bin]]
-name = "emulator_executable"
+name = "rbgb"
 path = "src/main.rs"
+required-features = ["gui"]
 
 [dependencies]
-debug_print = "1.0.0"
-lazy_static = "1.5.0"
-sdl2 = "0.37.0"
-time = "0.3.41"
+sdl2 = { version = "0.37.0", optional = true }
+
+[features]
+gui = ["sdl2"]
 
 # Easiest to bundle on windows since theres not a super easy way to install
 [target.'cfg(windows)'.dependencies]
-sdl2 = { version = "0.37.0", features = ["bundled"] }
+sdl2 = { version = "0.37.0", features = ["bundled"], optional = true }
 
 [dev-dependencies]
 ntest = "0.9.3"

README.md

@@ -8,6 +8,7 @@ A simple Game Boy emulator written in Rust.
 - Shared Memory bank
 - Basic graphics rendering
 - ROM loading
+- Dependency free (emulator lib)
 
 ## Repo Basics
 
@@ -29,7 +30,7 @@ Before running this project ensure SDL2 is installed if you are not running with
 3. Run the emulator:
 
     ```bash
-    cargo run --release
+    cargo run --release --features gui
     ```
 
 4. Select a ROM \
@@ -67,7 +68,7 @@ To build and run tests locally:
 
 ## Acknowledgements
 
-Much of this was written and based off of [Codeslinger Gameboy](http://www.codeslinger.co.uk/pages/projects/gameboy/beginning.html). I needed this guide to get through most of this. Additionally, I learned about how the RZ80 worked from [RZ80](https://floooh.github.io/) and modified the CPU implementation of the LR35902 from  [rboy](https://github.com/mvdnes/rboy). Getting the CPU emulation to work was the hardest part of this project.
+Much of this was written and based off of [Codeslinger Gameboy](http://www.codeslinger.co.uk/pages/projects/gameboy/beginning.html). I needed this guide to get through most of this. Additionally, I learned about how the RZ80 worked from [RZ80](https://floooh.github.io/) and modified the CPU implementation of the LR35902 from  [rboy](https://github.com/mvdnes/rboy). Getting the CPU emulation to work was the hardest part of this project. Additionally this project includes the `debug_println` macro from the [debug_print](https://docs.rs/debug_print/latest/debug_print/) crate in order to make it dependency free for the library.
 
 ## License
 

src/emulator.rs

@@ -3,8 +3,8 @@ use std::{
     time::{Duration, Instant},
 };
 
+use crate::debug_println;
 use crate::types::{GameInput, KeyState};
-use debug_print::debug_println;
 
 mod cpu;
 mod graphics;
@@ -76,10 +76,8 @@ impl Emulator {
             return;
         }
         let frame_start = Instant::now();
-        // debug_println!("Main Loop");
         let mut num_cycles: u32 = 0;
         while num_cycles < Self::MAXCYCLES {
-            //debug_println!("Program Counter: 0x{:X}", self.cpu.registers.val_pc());
             let cycles = self.cpu.execute_next_opcode(false);
             num_cycles += cycles as u32;
             self.cpu.timers.update_timers(cycles as i32);

src/emulator/graphics.rs

@@ -1,7 +1,3 @@
-#![allow(dead_code)]
-#[allow(unused_imports)]
-use debug_print::debug_println;
-
 use crate::emulator::mem::*;
 use crate::types::*;
 
@@ -26,70 +22,18 @@ impl Screen {
         }
     }
 
-    pub fn clear(&mut self, color: u8) {
-        let (r, g, b) = Self::color_to_rgb(color);
-        for chunk in self.buffer.chunks_mut(3) {
-            chunk[0] = r;
-            chunk[1] = g;
-            chunk[2] = b;
-        }
-    }
-
-    pub fn set_pixel(&mut self, x: usize, y: usize, color: u8) {
-        if x >= SCREEN_WIDTH as usize || y >= SCREEN_HEIGHT as usize {
-            return;
-        }
-        let idx = (y * SCREEN_WIDTH as usize + x) * 3;
-        let (r, g, b) = Self::color_to_rgb(color);
-        self.buffer[idx] = r;
-        self.buffer[idx + 1] = g;
-        self.buffer[idx + 2] = b;
-    }
-
-    pub fn get_pixel(&self, x: usize, y: usize) -> u8 {
-        if x >= SCREEN_WIDTH as usize || y >= SCREEN_HEIGHT as usize {
-            return 0;
-        }
-        let idx = (y * SCREEN_WIDTH as usize + x) * 3;
-        let r = self.buffer[idx];
-        let g = self.buffer[idx + 1];
-        let b = self.buffer[idx + 2];
-        Self::rgb_to_color(r, g, b)
-    }
-    fn color_to_rgb(color: u8) -> (u8, u8, u8) {
-        match color {
-            0 => (255, 255, 255),
-            1 => (0xCC, 0xCC, 0xCC),
-            2 => (0x77, 0x77, 0x77),
-            _ => (0, 0, 0),
-        }
-    }
-
-    fn rgb_to_color(r: u8, g: u8, b: u8) -> u8 {
-        match (r, g, b) {
-            (255, 255, 255) => 0,
-            (0xCC, 0xCC, 0xCC) => 1,
-            (0x77, 0x77, 0x77) => 2,
-            _ => 3,
-        }
-    }
-
     pub fn update_screen(&mut self, cycles: i32) {
-        // debug_println!("Screen update!");
-
         self.set_lcd_status();
 
         if self.is_lcd_enabled() {
             self.scanline_counter -= cycles;
         } else {
             // LCD is not enabled so do nothing
-            //debug_println!("LCD Disabled");
             return;
         }
 
         let mut mem = self.device_memory.lock().unwrap();
 
-        // debug_println!("Check scanlines!");
         if self.scanline_counter <= 0 {
             // Time to move onto the next scanline
             let scanline = mem.read_byte(CURRENT_SCANLINE).wrapping_add(1);
@@ -98,7 +42,6 @@ impl Screen {
             self.scanline_counter = 456;
 
             // we are now in the vertical blank period
-            // debug_println!("Current Scanline is {scanline}");
             if scanline == 144 {
                 mem.request_interrupt(0);
             }
@@ -132,7 +75,6 @@ impl Screen {
     }
 
     fn render_tiles(&mut self, control: Byte) {
-        // debug_println!("Rendering tile, control: {:b}", control);
         let mem = self.device_memory.lock().unwrap();
 
         let mut unsigned = true;
@@ -211,7 +153,6 @@ impl Screen {
             }
 
             let idx = (current_line as usize * SCREEN_WIDTH as usize + pixel as usize) * 3;
-            //debug_println!("Writing idx: {idx}");
             self.buffer[idx] = red;
             self.buffer[idx + 1] = green;
             self.buffer[idx + 2] = blue;
@@ -333,8 +274,6 @@ impl Screen {
     }
 
     fn set_lcd_status(&mut self) {
-        // debug_println!("Updating LCD Status!");
-
         let lcd_enabled = self.is_lcd_enabled();
         // Gets lock on memory
         let mut mem = self.device_memory.lock().unwrap();
@@ -359,8 +298,6 @@ impl Screen {
         let mode;
         let mut require_interrupt = false;
 
-        // debug_println!("Current scanline is {current_line} and mode is {current_mode}");
-
         // in vblank so mode is set to 1
         if current_line >= 144 {
             mode = 1;
@@ -408,11 +345,8 @@ impl Screen {
 
     fn is_lcd_enabled(&mut self) -> bool {
         // Check bit 7 of LCD Control register (0xFF40)
-        // debug_println!("Checking if LCD is enabled");
         let mem = self.device_memory.lock().unwrap();
-        // debug_println!("Lock aquired");
         mem.read_byte(LCD_CONTROL) & (1 << 7) != 0
-        // debug_println!("Check complete");
     }
 
     // TODO: Add more methods for drawing, sprites, etc.

src/emulator/joypad.rs

@@ -1,7 +1,4 @@
 //! Contains all code for interfacing io to the gameboy
-
-use debug_print::debug_println;
-
 use crate::types::{GameInput, KeyState};
 
 use super::mem::SharedMemory;
@@ -34,7 +31,6 @@ impl Joypad {
 
     /// Takes the input and affects the associated memory value with what it should be
     pub fn log_input(&mut self, input: GameInput, val: KeyState) {
-        debug_println!("Registering input: {:?}", input);
         match input {
             // mode 0 buttons
             GameInput::A => self.a = val,

src/emulator/mem.rs

@@ -5,8 +5,6 @@ use std::{
 
 /// Functions and storage for operating on device memory
 use crate::types::*;
-#[allow(unused_imports)]
-use debug_print::debug_println;
 
 pub type SharedMemory = Arc<Mutex<Memory>>;
 
@@ -229,10 +227,7 @@ impl Memory {
         //turns off the lower 5 bits of the banking mode
         let lower5: Byte = value & 31;
         let current = self.rom_banks.value();
-        // debug_println!("Current Banking Type: {:#?}", current);
-        // debug_println!("Maked Lower 5: {:#?}", lower5);
         let masked = (current & 224) | lower5;
-        // debug_println!("Post Banking Type: {:#?}", masked);
         self.rom_banks = CurrentRomBank::from(masked);
         if self.rom_banks == CurrentRomBank::Bank(0) {
             self.rom_banks = CurrentRomBank::Bank(1);
@@ -311,7 +306,6 @@ impl Memory {
     pub fn request_interrupt(&mut self, interrupt: Byte) {
         let mut request = self.read_byte(IF);
         request |= 1 << interrupt; // Sets the bit of the request
-        // debug_println!("Writing Interrupt {}", request);
         self.write_byte(IF, request);
     }
 
@@ -404,7 +398,6 @@ impl Memory {
         // the existing enables.
         let mut enabled = self.read_byte(IE);
         enabled |= 1 << interrupt; // Sets the bit of the request
-        // debug_println!("Enabling Interrupt {}", enabled);
         self.write_byte(IE, enabled);
     }
 
@@ -587,7 +580,6 @@ mod test {
         assert!(!mem.ram_write_enable);
 
         //Change rom bank
-        // debug_println!("\nCORRECTLY SET BANKS");
         mem.write_byte(0x2001, 0x0);
         assert_eq!(mem.rom_banks, CurrentRomBank::Bank(1));
         mem.write_byte(0x2001, 0x1);
@@ -605,7 +597,6 @@ mod test {
         assert_eq!(mem.rom_banks, CurrentRomBank::Bank(35));
 
         //Test banking set failure
-        // debug_println!("\nINCORRECTLY SET BANKS");
         mem.write_byte(0x2001, 0x40);
         assert_eq!(mem.rom_banks, CurrentRomBank::Bank(32));
 

src/lib.rs

@@ -1,3 +1,33 @@
+//! Game Boy emulator core.
+//!
+//! This crate provides the core emulation loop and subsystems for a classic
+//! Game Boy. The primary entry point is [`Emulator`], a struct that owns the
+//! CPU, memory, graphics, and input devices and drives them per frame.
+//!
+//! High-level flow:
+//! - Create an [`Emulator`] (starts paused).
+//! - Load a ROM with [`Emulator::load_rom`], which resets memory and CPU state.
+//! - Call [`Emulator::update`] once per frame to advance CPU, timers, and video.
+//! - Provide input through [`Emulator::game_input`], and read pixels from
+//!   [`Emulator::get_display_buffer`].
+//!
+//! The emulation state is backed by shared memory (`Arc<Mutex<...>>`) so the
+//! CPU, graphics, and joypad stay in sync with memory-mapped I/O.
+//!
+//! # Example
+//! ```no_run
+//! use rbgb::Emulator;
+//!
+//! fn main() -> Result<(), String> {
+//!     let mut emu = Emulator::new();
+//!     emu.load_rom("path/to/game.gb")?;
+//!     loop {
+//!         emu.update();
+//!         let _pixels = emu.get_display_buffer();
+//!         // Render pixels and handle input here.
+//!     }
+//! }
+//! ```
 pub mod emulator;
 mod types;
 

src/main.rs

@@ -1,3 +1,4 @@
+#[cfg(feature = "gui")]
 extern crate sdl2;
 
 mod emulator;