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use std::result;
use std::thread;
use std::time::{Duration, Instant};
use crate::graphics::{self, GraphicsContext};
use crate::input::{self, InputContext};
use crate::platform::{self, GraphicsDevice, Window};
use crate::time::{self, TimeContext, Timestep};
use crate::{Result, State, TetraError};
#[cfg(feature = "audio")]
use crate::audio::AudioDevice;
/// A struct containing all of the 'global' state within the framework.
pub struct Context {
pub(crate) window: Window,
pub(crate) device: GraphicsDevice,
#[cfg(feature = "audio")]
pub(crate) audio: AudioDevice,
pub(crate) graphics: GraphicsContext,
pub(crate) input: InputContext,
pub(crate) time: TimeContext,
pub(crate) running: bool,
pub(crate) quit_on_escape: bool,
pub(crate) fps_limit: bool,
}
impl Context {
pub(crate) fn new(settings: &ContextBuilder) -> Result<Context> {
// This needs to be initialized ASAP to avoid https://github.com/tomaka/rodio/issues/214
#[cfg(feature = "audio")]
let audio = AudioDevice::new();
let (window, gl_context, window_width, window_height) = Window::new(settings)?;
let mut device = GraphicsDevice::new(gl_context)?;
if settings.debug_info {
let device_info = device.get_info();
println!("OpenGL Vendor: {}", device_info.vendor);
println!("OpenGL Renderer: {}", device_info.renderer);
println!("OpenGL Version: {}", device_info.opengl_version);
println!("GLSL Version: {}", device_info.glsl_version);
}
let graphics = GraphicsContext::new(&mut device, window_width, window_height)?;
let input = InputContext::new();
let time = TimeContext::new(settings.timestep);
Ok(Context {
window,
device,
#[cfg(feature = "audio")]
audio,
graphics,
input,
time,
running: false,
quit_on_escape: settings.quit_on_escape,
fps_limit: settings.fps_limit
})
}
/// Runs the game.
///
/// The `init` parameter takes a function or closure that creates a
/// `State` implementation. A common pattern is to use method references
/// to pass in your state's constructor directly - see the example below
/// for how this works.
///
/// The error type returned by your `init` closure currently must match the error
/// type returned by your [`State`] methods. This limitation may be lifted
/// in the future.
///
/// # Errors
///
/// If the [`State`] returns an error from [`update`](State::update), [`draw`](State::draw)
/// or [`event`](State::event), the game will stop running and this method will
/// return the error.
///
/// # Examples
///
/// ```no_run
/// use tetra::{Context, ContextBuilder, State};
///
/// struct GameState;
///
/// impl GameState {
/// fn new(ctx: &mut Context) -> tetra::Result<GameState> {
/// Ok(GameState)
/// }
/// }
///
/// impl State for GameState { }
///
/// fn main() -> tetra::Result {
/// // Because GameState::new takes `&mut Context` and returns a `State` implementation
/// // wrapped in a `Result`, you can use it without a closure wrapper:
/// ContextBuilder::new("Hello, world!", 1280, 720)
/// .build()?
/// .run(GameState::new)
/// }
/// ```
///
pub fn run<S, F, E>(&mut self, init: F) -> result::Result<(), E>
where
S: State<E>,
F: FnOnce(&mut Context) -> result::Result<S, E>,
E: From<TetraError>,
{
let state = &mut init(self)?;
time::reset(self);
self.running = true;
self.window.set_visible(true);
let mut output = Ok(());
if let Err(e) = self.game_loop(state) {
output = Err(e);
}
self.running = false;
self.window.set_visible(false);
output
}
pub(crate) fn game_loop<S, E>(&mut self, state: &mut S) -> result::Result<(), E>
where
S: State<E>,
E: From<TetraError>,
{
let mut last_time = Instant::now();
while self.running {
let curr_time = Instant::now();
let diff_time = curr_time - last_time;
last_time = curr_time;
self.time.fps_tracker.push(diff_time);
platform::handle_events(self, state)?;
match self.time.tick_rate {
Some(tick_rate) => {
self.time.delta_time = tick_rate;
self.time.accumulator = (self.time.accumulator + diff_time).min(tick_rate * 8);
while self.time.accumulator >= tick_rate {
state.update(self)?;
input::clear(self);
self.time.accumulator -= tick_rate;
}
self.time.delta_time = diff_time;
}
None => {
self.time.delta_time = diff_time;
state.update(self)?;
input::clear(self);
}
}
state.draw(self)?;
graphics::present(self);
// This provides a sensible FPS limit when running without vsync, and
// avoids CPU usage skyrocketing on some systems.
if self.fps_limit {
thread::sleep(Duration::from_millis(1));
}
}
Ok(())
}
}
/// Settings that can be configured when starting up a game.
///
/// # Serde
///
/// Serialization and deserialization of this type (via [Serde](https://serde.rs/))
/// can be enabled via the `serde_support` feature.
///
/// Note that the available settings could change between releases of
/// Tetra (semver permitting). If you need a config file schema that will
/// be stable in the long term, consider making your own and then mapping
/// it to Tetra's API, rather than relying on `ContextBuilder` to not
/// change.
#[derive(Debug, Clone)]
#[cfg_attr(
feature = "serde_support",
derive(serde::Serialize, serde::Deserialize)
)]
pub struct ContextBuilder {
pub(crate) title: String,
pub(crate) window_width: i32,
pub(crate) window_height: i32,
pub(crate) vsync: bool,
pub(crate) timestep: Timestep,
pub(crate) fullscreen: bool,
pub(crate) maximized: bool,
pub(crate) minimized: bool,
pub(crate) resizable: bool,
pub(crate) borderless: bool,
pub(crate) multisampling: u8,
pub(crate) stencil_buffer: bool,
pub(crate) high_dpi: bool,
pub(crate) screen_saver_enabled: bool,
pub(crate) key_repeat: bool,
pub(crate) show_mouse: bool,
pub(crate) grab_mouse: bool,
pub(crate) relative_mouse_mode: bool,
pub(crate) quit_on_escape: bool,
pub(crate) fps_limit: bool,
pub(crate) debug_info: bool,
}
impl ContextBuilder {
/// Create a new `ContextBuilder`, with a title and window size.
pub fn new<S>(title: S, window_width: i32, window_height: i32) -> ContextBuilder
where
S: Into<String>,
{
ContextBuilder {
title: title.into(),
window_width,
window_height,
..ContextBuilder::default()
}
}
/// Sets the title of the window.
///
/// Defaults to `"Tetra"`.
pub fn title<S>(&mut self, title: S) -> &mut ContextBuilder
where
S: Into<String>,
{
self.title = title.into();
self
}
/// Sets the size of the window.
///
/// Defaults to `1280` by `720`.
pub fn size(&mut self, width: i32, height: i32) -> &mut ContextBuilder {
self.window_width = width;
self.window_height = height;
self
}
/// Enables or disables vsync.
///
/// Setting this flag does not guarantee that the requested vsync mode will be used -
/// some platforms do not support vsync, and others *enforce* vsync. If you want to
/// find out which vsync mode was actually chosen, you can call
/// [`window::is_vsync_enabled`](crate::window::is_vsync_enabled).
///
/// Defaults to `true`.
pub fn vsync(&mut self, vsync: bool) -> &mut ContextBuilder {
self.vsync = vsync;
self
}
/// Enables or disables the 1000 FPS limit.
///
/// The framework will sleep for 1 millisecond on the main thread if this flag is set to true
/// to provide a sensible FPS limit when running without vsync, and to avoid CPU usage
/// skyrocketing on some systems.
///
/// Defaults to `true`.
pub fn fps_limit(&mut self, fps_limit: bool) -> &mut ContextBuilder {
self.fps_limit = fps_limit;
self
}
/// Sets the game's timestep.
///
/// Defaults to `Timestep::Fixed(60.0)`.
pub fn timestep(&mut self, timestep: Timestep) -> &mut ContextBuilder {
self.timestep = timestep;
self
}
/// Sets whether or not the window should start in fullscreen.
///
/// Defaults to `false`.
pub fn fullscreen(&mut self, fullscreen: bool) -> &mut ContextBuilder {
self.fullscreen = fullscreen;
self
}
/// Sets whether or not the window should start maximized.
///
/// Defaults to `false`.
pub fn maximized(&mut self, maximized: bool) -> &mut ContextBuilder {
self.maximized = maximized;
self
}
/// Sets whether or not the window should start minimized.
///
/// Defaults to `false`.
pub fn minimized(&mut self, minimized: bool) -> &mut ContextBuilder {
self.minimized = minimized;
self
}
/// Sets whether or not the window should be resizable.
///
/// Defaults to `false`.
pub fn resizable(&mut self, resizable: bool) -> &mut ContextBuilder {
self.resizable = resizable;
self
}
/// Sets whether or not the window should be borderless.
///
/// Defaults to `false`.
pub fn borderless(&mut self, borderless: bool) -> &mut ContextBuilder {
self.borderless = borderless;
self
}
/// Sets the number of samples that should be used for multisample anti-aliasing.
///
/// The number of samples that can be used varies between graphics cards - `2`, `4` and `8` are reasonably
/// well supported. Setting the number of samples to `0` will disable multisampling.
///
/// Note that this setting only applies to the main backbuffer - multisampled canvases can
/// be created via [`Canvas::builder`](crate::graphics::Canvas::builder).
///
/// Defaults to `0`.
pub fn multisampling(&mut self, multisampling: u8) -> &mut ContextBuilder {
self.multisampling = multisampling;
self
}
/// Sets whether or not the window should have a stencil buffer.
///
/// If this is enabled, you can use the stencil functions in the
/// [`graphics`](crate::graphics) module when rendering to the main backbuffer.
///
/// Note that this setting only applies to the main backbuffer - to create a canvas with
/// a stencil buffer, use [`Canvas::builder`](crate::graphics::Canvas::builder).
///
/// Defaults to `false`.
pub fn stencil_buffer(&mut self, stencil_buffer: bool) -> &mut ContextBuilder {
self.stencil_buffer = stencil_buffer;
self
}
/// Sets whether or not the window should use a high-DPI backbuffer, on platforms
/// that support it (e.g. MacOS with a retina display).
///
/// Note that you may also need some platform-specific config to enable high-DPI
/// rendering:
///
/// * On Windows, set [`dpiAware`](https://docs.microsoft.com/en-gb/windows/win32/sbscs/application-manifests#dpiaware)
/// to `true/pm` and [`dpiAwareness`](https://docs.microsoft.com/en-gb/windows/win32/sbscs/application-manifests#dpiawareness)
/// to `permonitorv2` in your application manifest. This should enable the best behaviour available, regardless of how
/// old the user's version of Windows is.
/// * The [`embed-resource`](https://crates.io/crates/embed-resource) crate can be used to automate embedding
/// an application manifest.
/// * Alternatively, you can use the [`SetProcessDPIAware`](https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setprocessdpiaware)
/// or [`SetProcessDpiAwareness`](https://docs.microsoft.com/en-us/windows/desktop/api/shellscalingapi/nf-shellscalingapi-setprocessdpiawareness)
/// Windows API functions to change these settings programatically, but Microsoft recommend not to do this.
/// * On Mac, set [`NSHighResolutionCapable`](https://developer.apple.com/documentation/bundleresources/information_property_list/nshighresolutioncapable)
/// to `true` in your Info.plist. This is the default on Catalina and higher.
///
/// Defaults to `false`.
pub fn high_dpi(&mut self, high_dpi: bool) -> &mut ContextBuilder {
self.high_dpi = high_dpi;
self
}
/// Sets whether or not the user's screen saver can be displayed while the game is running.
///
/// Defaults to `false`.
pub fn screen_saver_enabled(&mut self, screen_saver_enabled: bool) -> &mut ContextBuilder {
self.screen_saver_enabled = screen_saver_enabled;
self
}
/// Sets whether or not key repeat should be enabled.
///
/// Normally, a [`KeyPressed`](crate::Event::KeyPressed) event will only be fired once, when
/// the key is initially pressed. Enabling key repeat causes `KeyPressed` events to be fired
/// continuously while the key is held down.
///
/// Defaults to `false`.
pub fn key_repeat(&mut self, key_repeat: bool) -> &mut ContextBuilder {
self.key_repeat = key_repeat;
self
}
/// Sets whether or not the mouse cursor should be visible when it is within the
/// game window.
///
/// Defaults to `false`.
pub fn show_mouse(&mut self, show_mouse: bool) -> &mut ContextBuilder {
self.show_mouse = show_mouse;
self
}
/// Sets whether or not the mouse cursor should be grabbed by the game window
/// at startup.
///
/// Defaults to `false`.
pub fn grab_mouse(&mut self, grab_mouse: bool) -> &mut ContextBuilder {
self.grab_mouse = grab_mouse;
self
}
/// Sets whether or not relative mouse mode should be enabled.
///
/// While the mouse is in relative mode, the cursor is hidden and can move beyond the
/// bounds of the window. The `delta` field of [`Event::MouseMoved`](crate::lifecycle::Event::MouseMoved)
/// can then be used to track the cursor's changes in position. This is useful
/// when implementing control schemes that require the mouse to be able to
/// move infinitely in any direction (for example, FPS-style movement).
///
/// While this mode is enabled, the absolute position of the mouse may not be updated -
/// as such, you should not rely on it.
///
/// Defaults to `false`.
pub fn relative_mouse_mode(&mut self, relative_mouse_mode: bool) -> &mut ContextBuilder {
self.relative_mouse_mode = relative_mouse_mode;
self
}
/// Sets whether or not the game should close when the Escape key is pressed.
///
/// Defaults to `false`.
pub fn quit_on_escape(&mut self, quit_on_escape: bool) -> &mut ContextBuilder {
self.quit_on_escape = quit_on_escape;
self
}
/// Sets whether or not the game should print out debug info at startup.
/// Please include this if you're submitting a bug report!
pub fn debug_info(&mut self, debug_info: bool) -> &mut ContextBuilder {
self.debug_info = debug_info;
self
}
/// Builds the context.
///
/// # Errors
///
/// * [`TetraError::PlatformError`] will be returned if the context cannot be initialized.
pub fn build(&self) -> Result<Context> {
Context::new(self)
}
}
impl Default for ContextBuilder {
fn default() -> ContextBuilder {
ContextBuilder {
title: "Tetra".into(),
window_width: 1280,
window_height: 720,
vsync: true,
timestep: Timestep::Fixed(60.0),
fullscreen: false,
maximized: false,
minimized: false,
resizable: false,
borderless: false,
multisampling: 0,
stencil_buffer: false,
high_dpi: false,
screen_saver_enabled: false,
key_repeat: false,
show_mouse: false,
grab_mouse: false,
relative_mouse_mode: false,
quit_on_escape: false,
fps_limit: true,
debug_info: false,
}
}
}