Add minimal-sdl2 example (#48)

Cargo.lock

@@ -91,6 +91,17 @@ name = "base-x"
 version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "beryllium"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "fermium 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "objc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "phantom-fields 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "raw-window-handle 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -245,6 +256,16 @@ dependencies = [
  "termcolor 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "fermium"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "fnv"
 version = "1.0.6"
@@ -765,10 +786,21 @@ name = "percent-encoding"
 version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "phantom-fields"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.44 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "pixels"
 version = "0.0.2"
 dependencies = [
+ "beryllium 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "getrandom 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1514,6 +1546,7 @@ dependencies = [
 "checksum backtrace 0.3.40 (registry+https://github.com/rust-lang/crates.io-index)" = "924c76597f0d9ca25d762c25a4d369d51267536465dc5064bdf0eb073ed477ea"
 "checksum backtrace-sys 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)" = "5d6575f128516de27e3ce99689419835fce9643a9b215a14d2b5b685be018491"
 "checksum base-x 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "1b20b618342cf9891c292c4f5ac2cde7287cc5c87e87e9c769d617793607dec1"
+"checksum beryllium 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1c821518d537a3ac0299396c4cfe84a877c0d83c494fd5c4310ec87873711d12"
 "checksum bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 "checksum block 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "0d8c1fef690941d3e7788d328517591fecc684c084084702d6ff1641e993699a"
 "checksum bumpalo 2.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ad807f2fc2bf185eeb98ff3a901bd46dc5ad58163d0fa4577ba0d25674d71708"
@@ -1535,6 +1568,7 @@ dependencies = [
 "checksum dlib 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "77e51249a9d823a4cb79e3eca6dcd756153e8ed0157b6c04775d04bf1b13b76a"
 "checksum downcast-rs 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "52ba6eb47c2131e784a38b726eb54c1e1484904f013e576a25354d0124161af6"
 "checksum env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
+"checksum fermium 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6989d270a6fa93ffa2c4c1c7c2ef56c8315d2aa099e000e413665808a4c68050"
 "checksum fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "2fad85553e09a6f881f739c29f0b00b0f01357c743266d478b68951ce23285f3"
 "checksum foreign-types 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f6f339eb8adc052cd2ca78910fda869aefa38d22d5cb648e6485e4d3fc06f3b1"
 "checksum foreign-types-shared 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "00b0228411908ca8685dba7fc2cdd70ec9990a6e753e89b6ac91a84c40fbaf4b"
@@ -1590,6 +1624,7 @@ dependencies = [
 "checksum parking_lot_core 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b876b1b9e7ac6e1a74a6da34d25c42e17e8862aa409cbbbdcfc8d86c6f3bc62b"
 "checksum pcx 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "1b00b062973776578e7863f8395f86e821760d827384f1ad9371d0893c87481a"
 "checksum percent-encoding 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d4fd5641d01c8f18a23da7b6fe29298ff4b55afcccdf78973b24cf3175fee32e"
+"checksum phantom-fields 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "cc7d5c2ec53ed64f6d636d44717906952de3d7930178b680b272c62fdd7e7968"
 "checksum pkg-config 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)" = "05da548ad6865900e60eaba7f589cc0783590a92e940c26953ff81ddbab2d677"
 "checksum proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)" = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
 "checksum proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "9c9e470a8dc4aeae2dee2f335e8f533e2d4b347e1434e5671afc49b054592f27"

Cargo.toml

@@ -27,6 +27,7 @@ wgpu = "0.4"
 
 # These are only used by the examples, and enabled with features
 # See: https://github.com/rust-lang/cargo/issues/1982
+beryllium = { version = " 0.1", optional = true }
 byteorder = { version = "1.3", optional = true }
 env_logger = { version = "0.7", optional = true }
 getrandom = { version = "0.1", optional = true }
@@ -50,6 +51,10 @@ required-features = ["conway"]
 name = "invaders"
 required-features = ["invaders"]
 
+[[example]]
+name = "minimal-sdl2"
+required-features = ["minimal-sdl2"]
+
 [[example]]
 name = "minimal-winit"
 required-features = ["minimal-winit"]
@@ -58,10 +63,12 @@ required-features = ["minimal-winit"]
 default = []
 log-deps = ["env_logger", "log"]
 random-deps = ["byteorder", "getrandom", "randomize"]
+sdl2-deps = ["beryllium"]
 winit-deps = ["winit", "winit_input_helper"]
 
 conway = ["line_drawing", "log-deps", "random-deps", "winit-deps"]
 invaders = ["gilrs", "log-deps", "random-deps", "simple-invaders", "winit-deps"]
+minimal-sdl2 = ["log-deps", "sdl2-deps"]
 minimal-winit = ["log-deps", "winit-deps"]
 
 [workspace]

examples/minimal-sdl2/README.md

@@ -0,0 +1,17 @@
+# Hello Pixels
+
+![Hello Pixels](../../img/minimal-sdl2.png)
+
+Minimal example with SDL2 using `beryllium`.
+
+## Running
+
+```bash
+cargo run --release --example minimal-sdl2 --features minimal-sdl2
+```
+
+## About
+
+This example demonstrates the absolute minimum for creating an SDL2 window and pixel buffer. It animates a purple box moving on a blue background, just for _something_ interesting to display.
+
+The example currently does not run on macOS. See [#47](https://github.com/parasyte/pixels/issues/47) for details.

examples/minimal-sdl2/main.rs

@@ -0,0 +1,120 @@
+#![deny(clippy::all)]
+#![forbid(unsafe_code)]
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
+
+use beryllium::*;
+use pixels::{wgpu::Surface, Pixels, SurfaceTexture};
+
+const WIDTH: u32 = 320;
+const HEIGHT: u32 = 240;
+const BOX_SIZE: i16 = 64;
+
+/// Representation of the application state. In this example, a box will bounce around the screen.
+struct World {
+    box_x: i16,
+    box_y: i16,
+    velocity_x: i16,
+    velocity_y: i16,
+}
+
+fn main() -> Result<(), String> {
+    env_logger::init();
+    let sdl = beryllium::init()?;
+    let window = sdl.create_window(
+        "Hello Pixels",
+        WINDOW_POSITION_CENTERED,
+        WINDOW_POSITION_CENTERED,
+        WIDTH as i32,
+        HEIGHT as i32,
+        WindowFlags::default(),
+    )?;
+    window.set_minimum_size(WIDTH as i32, HEIGHT as i32);
+    window.set_resizable(true);
+
+    let mut pixels = {
+        let surface = Surface::create(&window);
+        let surface_texture = SurfaceTexture::new(WIDTH, HEIGHT, surface);
+        Pixels::new(WIDTH, HEIGHT, surface_texture).map_err(|e| format!("{:?}", e))?
+    };
+    let mut world = World::new();
+
+    'game_loop: loop {
+        while let Some(event) = sdl.poll_event() {
+            match event {
+                // Close events
+                Event::Quit { .. } => break 'game_loop,
+                Event::Keyboard {
+                    key_info:
+                        KeyInfo {
+                            keycode: Some(key), ..
+                        },
+                    ..
+                } if key == Keycode::Escape => break 'game_loop,
+
+                // Resize the window
+                Event::WindowSizeChanged { width, height, .. } => {
+                    pixels.resize(width as u32, height as u32)
+                }
+
+                _ => (),
+            }
+        }
+
+        // Update internal state
+        world.update();
+
+        // Draw the current frame
+        world.draw(pixels.get_frame());
+        pixels.render();
+    }
+
+    Ok(())
+}
+
+impl World {
+    /// Create a new `World` instance that can draw a moving box.
+    fn new() -> Self {
+        Self {
+            box_x: 24,
+            box_y: 16,
+            velocity_x: 1,
+            velocity_y: 1,
+        }
+    }
+
+    /// Update the `World` internal state; bounce the box around the screen.
+    fn update(&mut self) {
+        if self.box_x <= 0 || self.box_x + BOX_SIZE - 1 >= WIDTH as i16 {
+            self.velocity_x *= -1;
+        }
+        if self.box_y <= 0 || self.box_y + BOX_SIZE - 1 >= HEIGHT as i16 {
+            self.velocity_y *= -1;
+        }
+
+        self.box_x += self.velocity_x;
+        self.box_y += self.velocity_y;
+    }
+
+    /// Draw the `World` state to the frame buffer.
+    ///
+    /// Assumes the default texture format: [`wgpu::TextureFormat::Rgba8UnormSrgb`]
+    fn draw(&self, frame: &mut [u8]) {
+        for (i, pixel) in frame.chunks_exact_mut(4).enumerate() {
+            let x = (i % WIDTH as usize) as i16;
+            let y = (i / WIDTH as usize) as i16;
+
+            let inside_the_box = x >= self.box_x
+                && x < self.box_x + BOX_SIZE
+                && y >= self.box_y
+                && y < self.box_y + BOX_SIZE;
+
+            let rgba = if inside_the_box {
+                [0x5e, 0x48, 0xe8, 0xff]
+            } else {
+                [0x48, 0xb2, 0xe8, 0xff]
+            };
+
+            pixel.copy_from_slice(&rgba);
+        }
+    }
+}