Sprite

Sprite is just a quad mesh that is always facing camera. It has size, color, rotation around "look" axis and a texture. Sprites are useful mostly for projectiles, like glowing plasma, and for things that should always face a camera.

⚠️ It should be noted that sprites are not meant to be used for 2D games, they're only for 3D. Use Rectangle node if you need 2D sprites, they have optimized renderer which can handle tons of sprites at once (sprite batching).

How to create

A sprite instance could be created using SpriteBuilder:

#![allow(unused)]
fn main() {
extern crate fyrox;
use fyrox::{
    core::{color::Color, pool::Handle},
    scene::{base::BaseBuilder, node::Node, sprite::SpriteBuilder, Scene},
};

fn create_sprite(scene: &mut Scene) -> Handle<Node> {
    SpriteBuilder::new(BaseBuilder::new())
        .with_size(2.0)
        .with_rotation(45.0f32.to_radians())
        .with_color(Color::RED)
        .build(&mut scene.graph)
}
}

A sprite with a texture could be created by using .with_texture method of the builder:

#![allow(unused)]
fn main() {
extern crate fyrox;
use fyrox::{
    core::pool::Handle,
    engine::resource_manager::ResourceManager,
    scene::{base::BaseBuilder, node::Node, sprite::SpriteBuilder, Scene},
};

fn create_sprite(scene: &mut Scene, resource_manager: ResourceManager) -> Handle<Node> {
    SpriteBuilder::new(BaseBuilder::new())
        .with_texture(resource_manager.request_texture("path/to/your/texture.png"))
        .build(&mut scene.graph)
}
}

General rules

Sprites must not be used to create any visual effects that involve many particles. You should use particle systems for that. Why so? Particles systems are very well optimized for managing huge amounts of particles at the same time, but sprites are not. Each sprite is quite heavy to be used as a particle in particle systems, it has a lot of "useless" info that will eat a lot of memory.

⚠️ Currently, the renderer will render each sprite in a separate draw call, which is very inefficient. So you should avoid creating lots of sprites.

Limitations

Sprites are not supporting any sort of lighting, if you need lighted sprites, you need to create your own render pass and use Mesh node with custom shader that will orient all faces towards camera and will do lighting calculations.