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use core::specs::prelude::{Dispatcher, DispatcherBuilder, System, World};
use core::{ArcThreadPool, SystemBundle};
use error::{Error, Result};
use renderer::pipe::pass::Pass;
use std::path::Path;
/// Initialise trait for game data
pub trait DataInit<T> {
/// Build game data
fn build(self, world: &mut World) -> T;
}
/// Default game data
pub struct GameData<'a, 'b> {
dispatcher: Dispatcher<'a, 'b>,
}
impl<'a, 'b> GameData<'a, 'b> {
/// Create new game data
pub fn new(dispatcher: Dispatcher<'a, 'b>) -> Self {
GameData { dispatcher }
}
/// Update game data
pub fn update(&mut self, world: &World) {
self.dispatcher.dispatch(&world.res);
}
}
/// Builder for default game data
pub struct GameDataBuilder<'a, 'b> {
disp_builder: DispatcherBuilder<'a, 'b>,
}
impl<'a, 'b> Default for GameDataBuilder<'a, 'b> {
fn default() -> Self {
GameDataBuilder::new()
}
}
impl<'a, 'b> GameDataBuilder<'a, 'b> {
/// Create new builder
pub fn new() -> Self {
GameDataBuilder {
disp_builder: DispatcherBuilder::new(),
}
}
/// Inserts a barrier which assures that all systems added before the
/// barrier are executed before the ones after this barrier.
///
/// Does nothing if there were no systems added since the last call to
/// `with_barrier()`. Thread-local systems are not affected by barriers;
/// they're always executed at the end.
///
/// # Returns
///
/// This function returns GameDataBuilder after it has modified it.
///
/// # Examples
///
/// ~~~no_run
/// use amethyst::prelude::*;
/// use amethyst::ecs::prelude::System;
///
/// struct NopSystem;
/// impl<'a> System<'a> for NopSystem {
/// type SystemData = ();
/// fn run(&mut self, (): Self::SystemData) {}
/// }
///
/// // Three systems are added in this example. The "tabby cat" & "tom cat"
/// // systems will both run in parallel. Only after both cat systems have
/// // run is the "doggo" system permitted to run them.
/// GameDataBuilder::default()
/// .with(NopSystem, "tabby cat", &[])
/// .with(NopSystem, "tom cat", &[])
/// .with_barrier()
/// .with(NopSystem, "doggo", &[]);
/// ~~~
pub fn with_barrier(mut self) -> Self {
self.disp_builder.add_barrier();
self
}
/// Adds a given system.
///
/// __Note:__ all dependencies must be added before you add the system.
///
/// # Parameters
///
/// - `system`: The system that is to be added to the game loop.
/// - `name`: A unique string to identify the system by. This is used for
/// dependency tracking. This name may be empty `""` string in which
/// case it cannot be referenced as a dependency.
/// - `dependencies`: A list of named system that _must_ have completed running
/// before this system is permitted to run.
/// This may be an empty list if there is no dependencies.
///
/// # Returns
///
/// This function returns GameDataBuilder after it has modified it.
///
/// # Type Parameters
///
/// - `S`: A type that implements the `System` trait.
///
/// # Panics
///
/// If two system are added that share an identical name, this function will panic.
/// Empty names are permitted, and this function will not panic if more then two are added.
///
/// If a dependency is referenced (by name), but has not previously been added this
/// function will panic.
///
/// # Examples
///
/// ~~~no_run
/// use amethyst::prelude::*;
/// use amethyst::ecs::prelude::System;
///
/// struct NopSystem;
/// impl<'a> System<'a> for NopSystem {
/// type SystemData = ();
/// fn run(&mut self, _: Self::SystemData) {}
/// }
///
/// GameDataBuilder::default()
/// // This will add the "foo" system to the game loop, in this case
/// // the "foo" system will not depend on any systems.
/// .with(NopSystem, "foo", &[])
/// // The "bar" system will only run after the "foo" system has completed
/// .with(NopSystem, "bar", &["foo"])
/// // It is legal to register a system with an empty name
/// .with(NopSystem, "", &[]);
/// ~~~
pub fn with<S>(mut self, system: S, name: &str, dependencies: &[&str]) -> Self
where
for<'c> S: System<'c> + Send + 'a,
{
self.disp_builder.add(system, name, dependencies);
self
}
/// Add a given thread-local system.
///
/// A thread-local system is one that _must_ run on the main thread of the
/// game. A thread-local system would be necessary typically to work
/// around vendor APIs that have thread dependent designs; an example
/// being OpenGL which uses a thread-local state machine to function.
///
/// All thread-local systems are executed sequentially after all
/// non-thread-local systems.
///
/// # Parameters
///
/// - `system`: The system that is to be added to the game loop.
///
/// # Returns
///
/// This function returns GameDataBuilder after it has modified it.
///
/// # Type Parameters
///
/// - `S`: A type that implements the `System` trait.
///
/// # Examples
///
/// ~~~no_run
/// use amethyst::prelude::*;
/// use amethyst::ecs::prelude::System;
///
/// struct NopSystem;
/// impl<'a> System<'a> for NopSystem {
/// type SystemData = ();
/// fn run(&mut self, _: Self::SystemData) {}
/// }
///
/// GameDataBuilder::default()
/// // the Nop system is registered here
/// .with_thread_local(NopSystem);
/// ~~~
pub fn with_thread_local<S>(mut self, system: S) -> Self
where
for<'c> S: System<'c> + 'b,
{
self.disp_builder.add_thread_local(system);
self
}
/// Add a given ECS bundle to the game loop.
///
/// A bundle is a container for registering a bunch of ECS systems at once.
///
/// # Parameters
///
/// - `bundle`: The bundle to add
///
/// # Returns
///
/// This function returns GameDataBuilder after it has modified it, this is
/// wrapped in a `Result`.
///
/// # Errors
///
/// This function creates systems, which use any number of dependent crates or APIs, which
/// could result in any number of errors.
/// See each individual bundle for a description of the errors it could produce.
///
pub fn with_bundle<B>(mut self, bundle: B) -> Result<Self>
where
B: SystemBundle<'a, 'b>,
{
bundle
.build(&mut self.disp_builder)
.map_err(|err| Error::Core(err))?;
Ok(self)
}
/// Create a basic renderer with a single given `Pass`, and optional support for the `DrawUi` pass.
///
/// Will set the clear color to black.
///
/// ### Parameters:
///
/// - `path`: Path to the `DisplayConfig` configuration file
/// - `pass`: The single pass in the render graph
/// - `with_ui`: If set to true, will add the UI render pass
pub fn with_basic_renderer<A, P>(self, path: A, pass: P, with_ui: bool) -> Result<Self>
where
A: AsRef<Path>,
P: Pass + 'b,
{
use config::Config;
use renderer::{DisplayConfig, Pipeline, RenderBundle, Stage};
use ui::DrawUi;
let config = DisplayConfig::load(path);
if with_ui {
let pipe = Pipeline::build().with_stage(
Stage::with_backbuffer()
.clear_target([0.0, 0.0, 0.0, 1.0], 1.0)
.with_pass(pass)
.with_pass(DrawUi::new()),
);
self.with_bundle(RenderBundle::new(pipe, Some(config)))
} else {
let pipe = Pipeline::build().with_stage(
Stage::with_backbuffer()
.clear_target([0.0, 0.0, 0.0, 1.0], 1.0)
.with_pass(pass),
);
self.with_bundle(RenderBundle::new(pipe, Some(config)))
}
}
}
impl<'a, 'b> DataInit<GameData<'a, 'b>> for GameDataBuilder<'a, 'b> {
fn build(self, world: &mut World) -> GameData<'a, 'b> {
#[cfg(not(no_threading))]
let pool = world.read_resource::<ArcThreadPool>().clone();
#[cfg(not(no_threading))]
let mut dispatcher = self.disp_builder.with_pool(pool).build();
#[cfg(no_threading)]
let mut dispatcher = self.disp_builder.build();
dispatcher.setup(&mut world.res);
GameData::new(dispatcher)
}
}
impl DataInit<()> for () {
fn build(self, _: &mut World) -> () {
()
}
}