Question

我有一个要构造的对象，需要其他对象：

[image] -> needed to construct -> [texture] -> needed to construct -> [sprite]

问题是我需要在纹理中交换图像以创建视觉效果。我有以下代码：

extern crate sfml;

use sfml::graphics::{Color, Image, RenderTarget, RenderWindow, Sprite, Texture};
use sfml::window::{Event, Key, Style};

const WIDTH: u32 = 1024;
const HEIGHT: u32 = 768;

fn main() {
    let mut window = RenderWindow::new(
        (WIDTH, HEIGHT),
        "Custom drawable",
        Style::CLOSE,
        &Default::default(),
    );

    let mut image = Image::from_color(WIDTH, HEIGHT, &Color::BLUE).unwrap();
    let mut texture = Texture::from_image(&image).unwrap();
    let sprite_canvas = Sprite::with_texture(&texture);

    let mut x: u32 = 0;

    loop {
        while let Some(event) = window.poll_event() {
            match event {
                Event::Closed
                | Event::KeyPressed {
                    code: Key::Escape, ..
                } => return,
                _ => {}
            }
        }
        x += 1;
        image.set_pixel(x, x, &Color::YELLOW);
        texture.update_from_image(&image, 0, 0);
        window.draw(&sprite_canvas);
        window.display()
    }
}

这是“货运”示例时出现的错误

error[E0502]: cannot borrow `texture` as mutable because it is also borrowed as immutable
  --> src/main.rs:35:9
   |
19 |     let sprite_canvas = Sprite::with_texture(&texture);
   |                                               ------- immutable borrow occurs here
...
35 |         texture.update_from_image(&image, 0, 0);
   |         ^^^^^^^ mutable borrow occurs here
...
39 | }
   | - immutable borrow ends here

出于性能方面的考虑，应避免复制或克隆纹理或图像；克隆大图像可能会导致性能下降。

我使它与这段代码一起工作，但是不确定是否是最好的解决方案，因为我正在每帧中重新创建纹理。

extern crate sfml;
use sfml::graphics::{Color, RenderTarget, RenderWindow, Sprite, Texture, Image, Transformable, Text, Font};
use sfml::window::{Event, Key, Style};

const WIDTH: u32 = 1024;
const HEIGHT: u32 = 768;

fn main() {
    let mut window = RenderWindow::new(
        (WIDTH, HEIGHT),
        "Custom drawable",
        Style::CLOSE,
        &Default::default(),
    );
    window.set_vertical_sync_enabled(true);

    let mut image_canvas = Image::from_color(WIDTH, HEIGHT, &Color::BLACK).unwrap();

    let mut x: f32 = 0.0;
    let mut y: f32 = 0.0;
    let mut image_swap = false;

    loop {
        while let Some(event) = window.poll_event() {
            match event {
                Event::Closed
                | Event::KeyPressed {
                    code: Key::Escape, ..
                } => return,
                _ => {}
            }
        }
        if Key::Left.is_pressed() {
            x -= 1.0;
        }

        if Key::Right.is_pressed() {
            x += 1.0;
        }

        if Key::Up.is_pressed() {
            y -= 1.0;
        }

        if Key::Down.is_pressed() {
            y += 1.0;
        }

        image_canvas.set_pixel(x as u32, y as u32, &Color::YELLOW);
        let texture_3 = Texture::from_image(&image_canvas).unwrap();
        let sprite_canvas = Sprite::with_texture(&texture_3);

        image_swap = !image_swap;

        window.clear(&Color::BLACK);
        window.draw(&sprite_canvas);
        window.display()
    }
}

如何交换sfml :: Texture基础的Image？

0 个答案: