From d1be0566969974bd70f2d77915b6936095c894c6 Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Fri, 6 Oct 2023 23:09:57 +0200
Subject: feat: add engine library base

---
 engine/src/lib.rs          | 74 ++++++++++++++++++++++++++++++++++++++++++++++
 engine/src/renderer/mod.rs | 57 +++++++++++++++++++++++++++++++++++
 engine/src/vector.rs       |  6 ++++
 3 files changed, 137 insertions(+)
 create mode 100644 engine/src/lib.rs
 create mode 100644 engine/src/renderer/mod.rs
 create mode 100644 engine/src/vector.rs

(limited to 'engine/src')

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,
+}
-- 
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