feat: add engine library base

6 files changed, 188 insertions, 1 deletions

diff --git a/Cargo.lock b/Cargo.lock
index dc88aa4..8199337 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -82,6 +82,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a26ae43d7bcc3b814de94796a5e736d4029efb0ee900c12e2d54c993ad1a1e07"
 
 [[package]]
+name = "engine"
+version = "0.1.0"
+dependencies = [
+ "gl",
+ "glfw",
+ "thiserror",
+]
+
+[[package]]
 name = "errno"
 version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -107,6 +116,26 @@ name = "game-newest"
 version = "0.1.0"
 
 [[package]]
+name = "gl"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a94edab108827d67608095e269cf862e60d920f144a5026d3dbcfd8b877fb404"
+dependencies = [
+ "gl_generator",
+]
+
+[[package]]
+name = "gl_generator"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a95dfc23a2b4a9a2f5ab41d194f8bfda3cabec42af4e39f08c339eb2a0c124d"
+dependencies = [
+ "khronos_api",
+ "log",
+ "xml-rs",
+]
+
+[[package]]
 name = "glfw"
 version = "0.1.0"
 dependencies = [
@@ -131,6 +160,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "khronos_api"
+version = "3.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2db585e1d738fc771bf08a151420d3ed193d9d895a36df7f6f8a9456b911ddc"
+
+[[package]]
 name = "lazy_static"
 version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -422,3 +457,9 @@ name = "windows_x86_64_msvc"
 version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ed94fce61571a4006852b7389a063ab983c02eb1bb37b47f8272ce92d06d9538"
+
+[[package]]
+name = "xml-rs"
+version = "0.8.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fcb9cbac069e033553e8bb871be2fbdffcab578eb25bd0f7c508cedc6dcd75a"
diff --git a/Cargo.toml b/Cargo.toml
index 96fc084..44b6558 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,6 +4,6 @@ version = "0.1.0"
 edition = "2021"
 
 [workspace]
-members = ["glfw"]
+members = ["glfw", "engine"]
 
 [dependencies]
diff --git a/engine/Cargo.toml b/engine/Cargo.toml
new file mode 100644
index 0000000..7b42cab
--- /dev/null
+++ b/engine/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "engine"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+glfw = { path = "../glfw" }
+thiserror = "1.0.49"
+gl = "0.14.0"
diff --git a/engine/src/lib.rs b/engine/src/lib.rs
new file mode 100644
index 0000000..618bc75
--- /dev/null
+++ b/engine/src/lib.rs
@@ -0,0 +1,74 @@
+#![deny(clippy::all, clippy::pedantic)]
+
+use glfw::Window;
+pub use glfw::WindowSize;
+
+mod renderer;
+
+pub mod vector;
+
+pub struct Engine
+{
+    window: Window,
+}
+
+impl Engine
+{
+    /// Creates and initializes a new engine.
+    ///
+    /// # Errors
+    /// Will return `Err` if window creation or window configuration fails.
+    pub fn new(window_size: &WindowSize, window_title: &str) -> Result<Self, Error>
+    {
+        let window = Window::create(window_size, window_title)
+            .map_err(Error::CreateWindowFailed)?;
+
+        window
+            .make_context_current()
+            .map_err(Error::ConfigureWindowFailed)?;
+
+        crate::renderer::initialize(&window).map_err(Error::InitializeRendererFailed)?;
+
+        Ok(Self { window })
+    }
+
+    /// Starts the engine.
+    ///
+    /// # Errors
+    /// Will return `Err` if updating the window fails.
+    pub fn start(&self, mut func: impl FnMut()) -> Result<(), Error>
+    {
+        while !self.window.should_close() {
+            func();
+
+            crate::renderer::render();
+
+            self.window
+                .swap_buffers()
+                .map_err(Error::UpdateWindowFailed)?;
+
+            self.window
+                .poll_events()
+                .map_err(Error::UpdateWindowFailed)?;
+        }
+
+        Ok(())
+    }
+}
+
+/// Engine Error
+#[derive(Debug, thiserror::Error)]
+pub enum Error
+{
+    #[error("Failed to create window")]
+    CreateWindowFailed(#[source] glfw::Error),
+
+    #[error("Failed to configure window")]
+    ConfigureWindowFailed(#[source] glfw::Error),
+
+    #[error("Failed to initialize renderer")]
+    InitializeRendererFailed(#[source] renderer::Error),
+
+    #[error("Failed to update window")]
+    UpdateWindowFailed(#[source] glfw::Error),
+}
diff --git a/engine/src/renderer/mod.rs b/engine/src/renderer/mod.rs
new file mode 100644
index 0000000..c34441c
--- /dev/null
+++ b/engine/src/renderer/mod.rs
@@ -0,0 +1,57 @@
+use std::ffi::{c_void, CString};
+use std::process::abort;
+
+use crate::vector::Vec2;
+
+pub fn initialize(window: &glfw::Window) -> Result<(), Error>
+{
+    gl::load_with(|symbol| {
+        let proc_name = unsafe { CString::from_vec_unchecked(symbol.into()) };
+
+        match window.get_proc_address(proc_name.as_c_str()) {
+            Ok(addr) => addr as *const c_void,
+            Err(err) => {
+                println!(
+                    "FATAL ERROR: Failed to get adress of OpenGL function {}. {}",
+                    symbol, err
+                );
+
+                abort();
+            }
+        }
+    });
+
+    let window_size = window.size().map_err(Error::GetWindowSizeFailed)?;
+
+    set_viewport(&Vec2 { x: 0, y: 0 }, &window_size);
+
+    Ok(())
+}
+
+pub fn render()
+{
+    unsafe {
+        gl::Clear(gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT);
+    }
+}
+
+/// Renderer error.
+#[derive(Debug, thiserror::Error)]
+pub enum Error
+{
+    #[error("Failed to get window size")]
+    GetWindowSizeFailed(#[source] glfw::Error),
+}
+
+fn set_viewport(position: &Vec2<u32>, size: &crate::WindowSize)
+{
+    unsafe {
+        #[allow(clippy::cast_possible_wrap)]
+        gl::Viewport(
+            position.x as i32,
+            position.y as i32,
+            size.width as i32,
+            size.height as i32,
+        );
+    }
+}
diff --git a/engine/src/vector.rs b/engine/src/vector.rs
new file mode 100644
index 0000000..92192bf
--- /dev/null
+++ b/engine/src/vector.rs
@@ -0,0 +1,6 @@
+#[derive(Debug)]
+pub struct Vec2<Value>
+{
+    pub x: Value,
+    pub y: Value,
+}