From d89a0c92aa0d89829a638e89a49f160de4ddeab0 Mon Sep 17 00:00:00 2001
From: David Johnson <john01dav@gmail.com>
Date: Sun, 16 Jan 2022 08:03:20 -0600
Subject: [PATCH] Added windows support and made example render something
 fancier

---
 Cargo.toml        |  5 ++++
 examples/winit.rs | 12 ++++++++-
 src/lib.rs        |  9 +++++--
 src/win32.rs      | 65 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 88 insertions(+), 3 deletions(-)
 create mode 100644 src/win32.rs

diff --git a/Cargo.toml b/Cargo.toml
index 83fa30c..da20db4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,7 +5,12 @@ edition = "2021"
 
 [dependencies]
 raw-window-handle = "0.4.2"
+
+[target.'cfg(target_os = "linux")'.dependencies]
 x11-dl = "2.19.1"
 
+[target.'cfg(target_os = "windows")'.dependencies]
+winapi = "0.3.9"
+
 [dev-dependencies]
 winit = "0.26.1"
\ No newline at end of file
diff --git a/examples/winit.rs b/examples/winit.rs
index 1fa128a..094e5c9 100644
--- a/examples/winit.rs
+++ b/examples/winit.rs
@@ -17,7 +17,17 @@ fn main() {
                     let size = graphics_context.window().inner_size();
                     (size.width, size.height)
                 };
-                let buffer = vec![0x00FF00FF; (width * height) as usize];
+                let buffer = (0..((width*height) as usize)).map(|index|{
+                    let y = index / (width as usize);
+                    let x = index % (width as usize);
+                    let red = x % 255;
+                    let green = y % 255;
+                    let blue = (x*y) % 255;
+
+                    let color = blue | (green << 8) | (red << 16);
+
+                    color as u32
+                }).collect::<Vec<_>>();
 
                 graphics_context.set_buffer(&buffer, width as u16, height as u16);
             }
diff --git a/src/lib.rs b/src/lib.rs
index 9f35689..37451a7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,7 +1,9 @@
+#[cfg(target_os = "linux")]
 mod x11;
+#[cfg(target_os = "windows")]
+mod win32;
 
 use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
-use crate::x11::X11Impl;
 
 pub struct GraphicsContext<W: HasRawWindowHandle>{
     window: W,
@@ -13,7 +15,10 @@ impl<W: HasRawWindowHandle> GraphicsContext<W> {
     pub unsafe fn new(window: W) -> Self{
         let raw_handle = window.raw_window_handle();
         let imple = match raw_handle{
-            RawWindowHandle::Xlib(xlib_handle) => Box::new(X11Impl::new(xlib_handle)),
+            #[cfg(target_os = "linux")]
+            RawWindowHandle::Xlib(xlib_handle) => Box::new(x11::X11Impl::new(xlib_handle)),
+            #[cfg(target_os = "windows")]
+            RawWindowHandle::Win32(win32_handle) => Box::new(win32::Win32Impl::new(&win32_handle)),
             unimplemented_handle_type => unimplemented!("Unsupported window handle type: {}.", window_handle_type_name(&unimplemented_handle_type))
         };
 
diff --git a/src/win32.rs b/src/win32.rs
new file mode 100644
index 0000000..a78f7db
--- /dev/null
+++ b/src/win32.rs
@@ -0,0 +1,65 @@
+use std::os::raw::c_int;
+use raw_window_handle::Win32Handle;
+use crate::GraphicsContextImpl;
+use winapi::um::wingdi::{BITMAPINFOHEADER, BI_BITFIELDS, RGBQUAD, StretchDIBits};
+use winapi::um::winuser::{ValidateRect, GetDC};
+use winapi::shared::windef::{HWND, HDC};
+
+pub struct Win32Impl{
+    window: HWND,
+    dc: HDC
+}
+
+// Wrap this so we can have a proper number of bmiColors to write in
+// From minifb
+#[repr(C)]
+struct BitmapInfo {
+    pub bmi_header: BITMAPINFOHEADER,
+    pub bmi_colors: [RGBQUAD; 3],
+}
+
+impl Win32Impl {
+
+    pub unsafe fn new(handle: &Win32Handle) -> Self{
+        let dc = GetDC(handle.hwnd as HWND);
+        Self{
+            dc,
+            window: handle.hwnd as HWND
+        }
+    }
+
+}
+
+impl GraphicsContextImpl for Win32Impl {
+    unsafe fn set_buffer(&mut self, buffer: &[u32], width: u16, height: u16) {
+        let mut bitmap_info: BitmapInfo = std::mem::zeroed();
+
+        bitmap_info.bmi_header.biSize = std::mem::size_of::<BITMAPINFOHEADER>() as u32;
+        bitmap_info.bmi_header.biPlanes = 1;
+        bitmap_info.bmi_header.biBitCount = 32;
+        bitmap_info.bmi_header.biCompression = BI_BITFIELDS;
+        bitmap_info.bmi_header.biWidth = width as i32;
+        bitmap_info.bmi_header.biHeight = -(height as i32);
+        bitmap_info.bmi_colors[0].rgbRed = 0xff;
+        bitmap_info.bmi_colors[1].rgbGreen = 0xff;
+        bitmap_info.bmi_colors[2].rgbBlue = 0xff;
+
+        StretchDIBits(
+            self.dc,
+            0,
+            0,
+            width as c_int,
+            height as c_int,
+            0,
+            0,
+            width as c_int,
+            height as c_int,
+            std::mem::transmute(buffer.as_ptr()),
+            std::mem::transmute(&bitmap_info),
+            winapi::um::wingdi::DIB_RGB_COLORS,
+            winapi::um::wingdi::SRCCOPY
+        );
+
+        ValidateRect(self.window, std::ptr::null_mut());
+    }
+}
\ No newline at end of file