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use crate::graphics::Color;
use crate::math::{Mat4, Vec2, Vec3};
/// Parameters that can be manipulated when drawing an object.
///
/// You can either use this as a builder by calling [`DrawParams::new`] and then chaining methods, or
/// construct it manually - whichever you find more pleasant to write.
#[derive(Debug, Clone, PartialEq)]
pub struct DrawParams {
/// The position that the graphic should be drawn at. Defaults to `(0.0, 0.0)`.
pub position: Vec2<f32>,
/// The scale that the graphic should be drawn at. Defaults to `(1.0, 1.0)`.
///
/// This can be set to a negative value to flip the graphic around the origin.
pub scale: Vec2<f32>,
/// The origin of the graphic. Defaults to `(0.0, 0.0)` (the top left).
///
/// This offset is applied before scaling, rotation and positioning. For example, if you have
/// a 16x16 image and set the origin to [8.0, 8.0], subsequent transformations will be performed
/// relative to the center of the image.
pub origin: Vec2<f32>,
/// The rotation of the graphic, in radians. Defaults to `0.0`.
pub rotation: f32,
/// A color to multiply the graphic by. Defaults to [`Color::WHITE`].
pub color: Color,
}
impl DrawParams {
/// Creates a new set of `DrawParams`.
pub fn new() -> DrawParams {
DrawParams::default()
}
/// Sets the position that the graphic should be drawn at.
pub fn position(mut self, position: Vec2<f32>) -> DrawParams {
self.position = position;
self
}
/// Sets the scale that the graphic should be drawn at.
pub fn scale(mut self, scale: Vec2<f32>) -> DrawParams {
self.scale = scale;
self
}
/// Sets the origin of the graphic.
pub fn origin(mut self, origin: Vec2<f32>) -> DrawParams {
self.origin = origin;
self
}
/// Sets the rotation of the graphic, in radians.
pub fn rotation(mut self, rotation: f32) -> DrawParams {
self.rotation = rotation;
self
}
/// Sets the color to multiply the graphic by.
pub fn color(mut self, color: Color) -> DrawParams {
self.color = color;
self
}
/// Creates a new transformation matrix equivalent to this set of params.
///
/// This method does not take into account `color`, as it cannot
/// be represented via a matrix.
pub fn to_matrix(&self) -> Mat4<f32> {
let mut matrix = Mat4::translation_2d(-self.origin);
matrix.scale_3d(Vec3::from(self.scale));
matrix.rotate_z(self.rotation);
matrix.translate_2d(self.position);
matrix
}
}
impl Default for DrawParams {
fn default() -> DrawParams {
DrawParams {
position: Vec2::new(0.0, 0.0),
scale: Vec2::new(1.0, 1.0),
origin: Vec2::new(0.0, 0.0),
rotation: 0.0,
color: Color::WHITE,
}
}
}
impl From<Vec2<f32>> for DrawParams {
fn from(position: Vec2<f32>) -> DrawParams {
DrawParams {
position,
..DrawParams::default()
}
}
}
impl From<DrawParams> for Mat4<f32> {
fn from(params: DrawParams) -> Self {
params.to_matrix()
}
}