Textures

You can create textures, draw on them, draw them onto other textures and apply them to objects in the world.

// width: 800, height: 600
let texture = Texture::create((800, 600))

See the code docs for Texture for possible draw commands.

Bitmap fonts

You can load LOTUS bitmap fonts to draw them onto a texture. To draw a bitmap font onto a texture you first need to have it loaded. See asset preloading if you need more control over the load process.

Bitmap font metadata

If you need metadata about the font, for example for getting the length of provided text, you need to load it first.

// try_load will return None as long as the font is not loaded. Just trying to load it
// will enqueue it to be loaded. After it's loaded it will return Some
if let Some(font) = BitmapFont::try_load(ContentId { user_id: 1000, sub_id: 1000 }) {
  let props = font.properties();
  let hello_len = font.text_len("hello", 1);
}

Drawing with a font

To draw with a font, you don’t need to load it manually, you can just use the Texture::draw_text method with a content id.

let texture = Texture::create((800, 600));
let font_id = ContentId { user_id: 1000, sub_id: 1000 };
let top_left = (0, 0);
let letter_spacing = 5;
let full_color = None;

texture.draw_text(
  font_id,
  "hello",
  top_left,
  letter_spacing,
  full_color,
  AlphaMode::Opaque
);

Technical details

Everything you draw on textures happens asynchronously, all Texture::draw_* methods just enqueue whatever you want to draw and the engine will process these in the background. This means that changes to textures may not be visible in the same frame. If you want to see your changes immediately you can call Texture::flush, which tries to apply all changes. Since for example a font may not be loaded that you want to draw, this may not actually draw everything. The Texture::flush method will return true if everything has been drawn and false otherwise. This also applies to reading pixels via Texture::read_pixel.