我正在尝试使用Piston进行一些游戏编程，但我正在努力使用Copy，因为它没有派生Clone或extern crate piston_window;
extern crate piston;
extern crate graphics;
extern crate opengl_graphics;
use opengl_graphics::Texture as Tex;
use piston_window::*;
use std::path::Path;
use opengl_graphics::GlGraphics;
#[derive(PartialEq)]
enum ObjectType {
Blocking,
Passing,
}
struct Object {
sprite: Tex,
obj_type: ObjectType,
position: Position,
}
struct Game {
gl: GlGraphics,
images: Vec<Object>,
player: Player,
}
struct Player {
sprite: Tex,
position: Position,
}
struct Position {
x: i32,
y: i32,
}
impl Game {
fn render(&mut self, args: &RenderArgs) {
let iter = self.images.iter();
let player = &self.player;
self.gl.draw(args.viewport(), |c, g| {
clear([1.0, 1.0, 1.0, 1.0], g);
for img in iter {
let pos = img.get_position();
let transform = c.transform.trans(((pos.x * 64)) as f64, ((pos.y * 64)) as f64);
image(img.get_sprite(), transform, g);
}
image(player.get_sprite(),
c.transform.trans((player.get_position().x * 64) as f64,
(player.get_position().y * 64) as f64),
g);
});
}
fn update(&mut self, args: &UpdateArgs) {}
}
。
fn main() {
let (width, height) = (64*10, 64*10);
let opengl = OpenGL::V3_2;
let mut window: PistonWindow =
WindowSettings::new("piston", (width, height))
.exit_on_esc(true)
.opengl(opengl)
.build()
.unwrap();
window.hide();
println!("Loading...");
let mut player = Player { sprite: Tex::from_path(&Path::new(
"./assets/player_n.png")).unwrap(),
position: Position { x: 3, y: 3 },
};
let mut game = Game {
gl: GlGraphics::new(opengl),
images: Vec::new(),
player: player,
};
for i in 0..10 {
for j in 0..10 {
if i == 0 || i == 9 || j == 0 || j == 9 {
let obj = Object { sprite: Tex::from_path(&Path::new(
"./assets/wall.png")).unwrap(),
obj_type: ObjectType::Blocking,
position: Position { x: i, y: j },
};
game.images.push(obj);
} else {
let obj = Object { sprite: Tex::from_path(&Path::new(
"./assets/floor.png")).unwrap(),
obj_type: ObjectType::Passing,
position: Position { x: i, y: j },
};
game.images.push(obj);
}
}
}
window.show();
while let Some(e) = window.next() {
if let Some(Button::Keyboard(key)) = e.press_args() {
let mut pos = game.player.position.clone();
let mut spr: Option<Tex> = None;
match key {
Key::Up => { pos.y -= 1; spr = Some(Tex::from_path(&Path::new(
"./assets/player_n.png")).unwrap()); },
Key::Down => { pos.y += 1; spr = Some(Tex::from_path(&Path::new(
"./assets/player_s.png")).unwrap()); },
Key::Left => { pos.x -= 1; spr = Some(Tex::from_path(&Path::new(
"./assets/player_w.png")).unwrap()); },
Key::Right => { pos.x += 1; spr = Some(Tex::from_path(&Path::new(
"./assets/player_e.png")).unwrap()); },
_ => (),
}
for elem in game.images.iter() {
if pos.x == elem.position.x && pos.y == elem.position.y && elem.obj_type == ObjectType::Passing {
game.player.position = pos;
game.player.sprite = spr.clone().unwrap();
}
}
}
if let Some(r) = e.render_args() {
game.render(&r);
}
if let Some(u) = e.update_args() {
game.update(&u);
}
}
}
主要游戏循环：
error: no method named `clone` found for type `std::option::Option<opengl_graphics::Texture>` in the current scope
--> src/main.rs:159:46
159 | game.player.sprite = spr.clone().unwrap();
| ^^^^^
|
= note: the method `clone` exists but the following trait bounds were not satisfied: `opengl_graphics::Texture : std::clone::Clone`
产生错误：
opengl_graphics::Texture我理解为什么会收到此错误，因为Copy未导出Option<opengl_texture>我无法克隆trait SyncCmsProxyService {
def head(path: String): String
def teaser(path: String): String
}
@Singleton
class DefaultSyncCmsProxyService @Inject()(implicit cache: CacheApi, wsClient: WSClient) extends SyncCmsProxyService with UrlBuilder with CacheAccessor{
private val log = Logger("application")
override def head(path: String) = {
log.debug("looking for head ...")
query(url(path), "$.payload[0].title")
}
override def teaser(path: String) = {
log.debug("looking for teaser ...")
query(url(path), "$.payload[0].content.teaserText")
}
private def query(url: String, jsonPath: String) = {
val key = s"${url}?${jsonPath}"
val payload = findInCache(key)
if (payload.isDefined) {
payload.get
}else{
val json = Json.parse(body(url))
val queried = JSONPath.query(jsonPath, json).as[String]
saveInCache(key, queried)
}
}
private def body(url: String) = {
cache.synchronized {
val body = findInCache(url)
if (body.isDefined) {
log.debug("found body in cache")
body.get
} else {
saveInCache(url, doCall(url))
}
}
}
private def doCall(url : String): String = {
import scala.concurrent.ExecutionContext.Implicits.global
log.debug("calling...")
val req = wsClient.url(url).get()
val f = req map { res =>
val status = res.status
log.debug(s"endpoint called! response status: ${status}")
if (status == 200) {
res.body
} else {
""
}
}
Await.result(f, 15.seconds)
}
}
。有什么办法解决这个问题？
我尝试弄乱引用，但这不起作用。
答案 0 :(得分：4)
如何复制/克隆既不派生的结构？
你不是。你唯一能做的就是对它进行一些参考。
在这种情况下，图书馆选择不实施Clone或Copy是一件非常好的事情。如果您能够克隆结构，那么您将经常和不必要地分配大量内存。相反，库已迫使您考虑何时分配该内存。其中一个解决方案是在应用程序启动时加载所有纹理并引用它们：
更改您的结构以保留参考：
#[derive(PartialEq)]
enum ObjectType {
Blocking,
Passing,
}
struct Object<'a> {
sprite: &'a Tex,
obj_type: ObjectType,
position: Position,
}
struct Game<'a> {
gl: GlGraphics,
images: Vec<Object<'a>>,
player: Player<'a>,
}
struct Player<'a> {
sprite: &'a Tex,
position: Position,
}
#[derive(Copy, Clone, PartialEq)]
struct Position {
x: i32,
y: i32,
}
struct Textures {
player_n: Tex,
player_s: Tex,
player_e: Tex,
player_w: Tex,
wall: Tex,
floor: Tex,
}
在main中尽早加载纹理。请注意，Path需要明确使用AsRef<Path>：
let textures = Textures {
player_n: Tex::from_path("./assets/player_n.png").unwrap(),
player_s: Tex::from_path("./assets/player_s.png").unwrap(),
player_e: Tex::from_path("./assets/player_e.png").unwrap(),
player_w: Tex::from_path("./assets/player_w.png").unwrap(),
wall: Tex::from_path("./assets/wall.png").unwrap(),
floor: Tex::from_path("./assets/floor.png").unwrap()
};
然后传递对这些纹理的引用：
match key {
Key::Up => {
pos.y -= 1;
spr = Some(&textures.player_n)
}
Key::Down => {
pos.y += 1;
spr = Some(&textures.player_s)
}
Key::Left => {
pos.x -= 1;
spr = Some(&textures.player_w)
}
Key::Right => {
pos.x += 1;
spr = Some(&textures.player_e)
}
_ => (),
}
for elem in game.images.iter() {
if pos == elem.position && elem.obj_type == ObjectType::Passing {
game.player.position = pos;
if let Some(spr) = spr {
game.player.sprite = spr;
}
}
}
请注意，这也会合并可能发生错误的位置。在循环的内部不再有unwrap。
由于代码不完整，我无法让您的代码完成编译，但这应该有助于开始：
error: no method named `render` found for type `Game<'_>` in the current scope
--> src/main.rs:122:18
|
122 | game.render(&r);
| ^^^^^^
|
= help: items from traits can only be used if the trait is implemented and in scope; the following trait defines an item `render`, perhaps you need to implement it:
= help: candidate #1: `piston_window::RenderEvent`
error: no method named `update` found for type `Game<'_>` in the current scope
--> src/main.rs:125:18
|
125 | game.update(&u);
| ^^^^^^
|
= help: items from traits can only be used if the trait is implemented and in scope; the following traits define an item `update`, perhaps you need to implement one of them:
= help: candidate #1: `piston_window::UpdateEvent`
= help: candidate #2: `piston_window::<unnamed>::UpdateTexture`
= help: candidate #3: `deflate::checksum::RollingChecksum`
= help: candidate #4: `cocoa::appkit::NSOpenGLContext`
= help: candidate #5: `cocoa::appkit::NSOpenGLContext`