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use crate::{ffi::graphics as ffi, graphics::FloatRect, system::Vector2f};
/// Define a 3x3 transform matrix.
///
/// A `Transform` specifies how to translate,
/// rotate, scale, shear, project, whatever things.
#[repr(C)]
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct Transform {
pub(crate) matrix: [f32; 16],
}
impl Transform {
/// Creates a new transform from a 3x3 matrix.
///
/// # Arguments
///
/// - *a00* : Element (0, 0) of the matrix
/// - *a01* : Element (0, 1) of the matrix
/// - *a02* : Element (0, 2) of the matrix
/// - *a10* : Element (1, 0) of the matrix
/// - *a11* : Element (1, 1) of the matrix
/// - *a12* : Element (1, 2) of the matrix
/// - *a20* : Element (2, 0) of the matrix
/// - *a21* : Element (2, 1) of the matrix
/// - *a22* : Element (2, 2) of the matrix
#[allow(clippy::too_many_arguments)]
#[must_use]
pub fn new(
a00: f32,
a01: f32,
a02: f32,
a10: f32,
a11: f32,
a12: f32,
a20: f32,
a21: f32,
a22: f32,
) -> Transform {
Self {
matrix: [
a00, a10, 0., a20, a01, a11, 0., a21, 0., 0., 1., 0., a02, a12, 0., a22,
],
}
}
/// Return the matrix
#[must_use]
pub fn get_matrix(&self) -> &[f32; 16] {
&self.matrix
}
/// The identity transform (does nothing)
pub const IDENTITY: Self = Self {
matrix: [
1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0,
],
};
/// Return the inverse of a transform
///
/// If the inverse cannot be computed, a new identity transform
/// is returned.
///
/// Return the inverse matrix
#[must_use]
pub fn inverse(&self) -> Transform {
// Directly translated from SFML source code.
let det = self.matrix[0]
* (self.matrix[15] * self.matrix[5] - self.matrix[7] * self.matrix[13])
- self.matrix[1]
* (self.matrix[15] * self.matrix[4] - self.matrix[7] * self.matrix[12])
+ self.matrix[3]
* (self.matrix[13] * self.matrix[4] - self.matrix[5] * self.matrix[12]);
// Compute the inverse if the determinant is not zero
// (don't use an epsilon because the determinant may *really* be tiny)
if det != 0. {
Self::new(
(self.matrix[15] * self.matrix[5] - self.matrix[7] * self.matrix[13]) / det,
-(self.matrix[15] * self.matrix[4] - self.matrix[7] * self.matrix[12]) / det,
(self.matrix[13] * self.matrix[4] - self.matrix[5] * self.matrix[12]) / det,
-(self.matrix[15] * self.matrix[1] - self.matrix[3] * self.matrix[13]) / det,
(self.matrix[15] * self.matrix[0] - self.matrix[3] * self.matrix[12]) / det,
-(self.matrix[13] * self.matrix[0] - self.matrix[1] * self.matrix[12]) / det,
(self.matrix[7] * self.matrix[1] - self.matrix[3] * self.matrix[5]) / det,
-(self.matrix[7] * self.matrix[0] - self.matrix[3] * self.matrix[4]) / det,
(self.matrix[5] * self.matrix[0] - self.matrix[1] * self.matrix[4]) / det,
)
} else {
Self::IDENTITY
}
}
/// Combine two transforms
///
/// The result is a transform that is equivalent to applying
/// transform followed by other. Mathematically, it is
/// equivalent to a matrix multiplication.
///
/// # Arguments
/// * other - Transform to combine to transform
pub fn combine(&mut self, other: &Transform) {
unsafe { ffi::sfTransform_combine(self, other) }
}
/// Combine a transform with a translation
///
/// # Arguments
/// * x - Offset to apply on X axis
/// * y - Offset to apply on Y axis
pub fn translate(&mut self, x: f32, y: f32) {
unsafe { ffi::sfTransform_translate(self, x, y) }
}
/// Combine the current transform with a rotation
///
/// # Arguments
/// * angle - Rotation angle, in degrees
pub fn rotate(&mut self, angle: f32) {
unsafe { ffi::sfTransform_rotate(self, angle) }
}
/// Combine the current transform with a rotation
///
/// The center of rotation is provided for convenience as a second
/// argument, so that you can build rotations around arbitrary points
/// more easily (and efficiently) than the usual
/// [translate(-center), rotate(angle), translate(center)].
///
/// # Arguments
/// * angle - Rotation angle, in degrees
/// * `center_x` - X coordinate of the center of rotation
/// * `center_y` - Y coordinate of the center of rotation
pub fn rotate_with_center(&mut self, angle: f32, center_x: f32, center_y: f32) {
unsafe { ffi::sfTransform_rotateWithCenter(self, angle, center_x, center_y) }
}
/// Combine the current transform with a scaling
///
/// # Arguments
/// * `scale_x` - Scaling factor on the X axis
/// * `scale_y` - Scaling factor on the Y axis
pub fn scale(&mut self, scale_x: f32, scale_y: f32) {
unsafe { ffi::sfTransform_scale(self, scale_x, scale_y) }
}
/// Combine the current transform with a scaling
///
/// The center of scaling is provided for convenience as a second
/// argument, so that you can build scaling around arbitrary points
/// more easily (and efficiently) than the usual
/// [translate(-center), scale(factors), translate(center)]
///
/// # Arguments
/// * `scale_x` - Scaling factor on X axis
/// * `scale_y` - Scaling factor on Y axis
/// * `center_x` - X coordinate of the center of scaling
/// * `center_y` - Y coordinate of the center of scaling
pub fn scale_with_center(&mut self, scale_x: f32, scale_y: f32, center_x: f32, center_y: f32) {
unsafe { ffi::sfTransform_scaleWithCenter(self, scale_x, scale_y, center_x, center_y) }
}
/// Apply a transform to a 2D point
///
/// # Arguments
/// * point - Point to transform
///
/// Return a transformed point
#[must_use]
pub fn transform_point(&self, point: Vector2f) -> Vector2f {
unsafe { ffi::sfTransform_transformPoint(self, point) }
}
/// Apply a transform to a rectangle
///
/// Since SFML doesn't provide support for oriented rectangles,
/// the result of this function is always an axis-aligned
/// rectangle. Which means that if the transform contains a
/// rotation, the bounding rectangle of the transformed rectangle
/// is returned.
///
/// # Arguments
/// rectangle - Rectangle to transform
///
/// Return the transformed rectangle
#[must_use]
pub fn transform_rect(&self, rectangle: FloatRect) -> FloatRect {
unsafe { ffi::sfTransform_transformRect(self, rectangle) }
}
}
impl Default for Transform {
fn default() -> Self {
Self::IDENTITY
}
}