Change Vsync setting to use Fifo present mode (#93)

And add a method to set `Mailbox` or other explicit modes.

Closes #88

examples/conway/src/main.rs

@@ -15,7 +15,7 @@ fn main() -> Result<(), Error> {
     env_logger::init();
     let event_loop = EventLoop::new();
     let mut input = WinitInputHelper::new();
-    let (window, surface, p_width, p_height, mut hidpi_factor) =
+    let (window, surface, p_width, p_height, mut _hidpi_factor) =
         create_window("Conway's Game of Life", &event_loop);
 
     let surface_texture = SurfaceTexture::new(p_width, p_height, surface);
@@ -110,7 +110,7 @@ fn main() -> Result<(), Error> {
             }
             // Adjust high DPI factor
             if let Some(factor) = input.scale_factor_changed() {
-                hidpi_factor = factor;
+                _hidpi_factor = factor;
             }
             // Resize the window
             if let Some(size) = input.window_resized() {

examples/invaders/src/main.rs

@@ -25,7 +25,7 @@ fn main() -> Result<(), Error> {
         .parse()
         .unwrap_or(false);
 
-    let (window, surface, width, height, mut hidpi_factor) =
+    let (window, surface, width, height, mut _hidpi_factor) =
         create_window("pixel invaders", &event_loop);
     let surface_texture = SurfaceTexture::new(width, height, surface);
     let mut pixels = Pixels::new(SCREEN_WIDTH as u32, SCREEN_HEIGHT as u32, surface_texture)?;
@@ -99,7 +99,7 @@ fn main() -> Result<(), Error> {
 
             // Adjust high DPI factor
             if let Some(factor) = input.scale_factor_changed() {
-                hidpi_factor = factor;
+                _hidpi_factor = factor;
             }
 
             // Resize the window

examples/minimal-winit/src/main.rs

@@ -34,7 +34,6 @@ fn main() -> Result<(), Error> {
             .build(&event_loop)
             .unwrap()
     };
-    let mut hidpi_factor = window.scale_factor();
 
     let mut pixels = {
         let surface = Surface::create(&window);
@@ -65,11 +64,6 @@ fn main() -> Result<(), Error> {
                 return;
             }
 
-            // Adjust high DPI factor
-            if let Some(factor) = input.scale_factor_changed() {
-                hidpi_factor = factor;
-            }
-
             // Resize the window
             if let Some(size) = input.window_resized() {
                 pixels.resize(size.width, size.height);

src/lib.rs

@@ -418,7 +418,7 @@ impl<'req> PixelsBuilder<'req> {
             width,
             height,
             pixel_aspect_ratio: 1.0,
-            present_mode: wgpu::PresentMode::Mailbox,
+            present_mode: wgpu::PresentMode::Fifo,
             surface_texture,
             texture_format: wgpu::TextureFormat::Rgba8UnormSrgb,
             renderer_factories: Vec::new(),
@@ -469,18 +469,30 @@ impl<'req> PixelsBuilder<'req> {
         self
     }
 
-    /// Enable or disable vsync.
+    /// Enable or disable Vsync.
     ///
     /// Vsync is enabled by default.
+    ///
+    /// The `wgpu` present mode will be set to `Fifo` when Vsync is enabled, or `Immediate` when
+    /// Vsync is disabled. To set the present mode to `Mailbox` or another value, use the
+    /// [`present_mode`] method.
     pub fn enable_vsync(mut self, enable_vsync: bool) -> PixelsBuilder<'req> {
         self.present_mode = if enable_vsync {
-            wgpu::PresentMode::Mailbox
+            wgpu::PresentMode::Fifo
         } else {
             wgpu::PresentMode::Immediate
         };
         self
     }
 
+    /// Set the `wgpu` present mode.
+    ///
+    /// This differs from [`enable_vsync`] by allowing the present mode to be set to any value.
+    pub fn present_mode(mut self, present_mode: wgpu::PresentMode) -> PixelsBuilder<'req> {
+        self.present_mode = present_mode;
+        self
+    }
+
     /// Set the texture format.
     ///
     /// The default value is [`wgpu::TextureFormat::Rgba8UnormSrgb`], which is 4 unsigned bytes in