godot/core/math/transform_2d.h
2024-03-04 18:17:10 +01:00

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/**************************************************************************/
/* transform_2d.h */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
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/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
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#ifndef TRANSFORM_2D_H
#define TRANSFORM_2D_H
#include "core/math/math_funcs.h"
#include "core/math/rect2.h"
#include "core/math/vector2.h"
#include "core/templates/vector.h"
class String;
struct _NO_DISCARD_ Transform2D {
// Warning #1: basis of Transform2D is stored differently from Basis. In terms of columns array, the basis matrix looks like "on paper":
// M = (columns[0][0] columns[1][0])
// (columns[0][1] columns[1][1])
// This is such that the columns, which can be interpreted as basis vectors of the coordinate system "painted" on the object, can be accessed as columns[i].
// Note that this is the opposite of the indices in mathematical texts, meaning: $M_{12}$ in a math book corresponds to columns[1][0] here.
// This requires additional care when working with explicit indices.
// See https://en.wikipedia.org/wiki/Row-_and_column-major_order for further reading.
// Warning #2: 2D be aware that unlike 3D code, 2D code uses a left-handed coordinate system: Y-axis points down,
// and angle is measure from +X to +Y in a clockwise-fashion.
Vector2 columns[3];
_FORCE_INLINE_ real_t tdotx(const Vector2 &p_v) const { return columns[0][0] * p_v.x + columns[1][0] * p_v.y; }
_FORCE_INLINE_ real_t tdoty(const Vector2 &p_v) const { return columns[0][1] * p_v.x + columns[1][1] * p_v.y; }
const Vector2 &operator[](int p_idx) const { return columns[p_idx]; }
Vector2 &operator[](int p_idx) { return columns[p_idx]; }
void invert();
Transform2D inverse() const;
void affine_invert();
Transform2D affine_inverse() const;
void set_rotation(real_t p_rot);
real_t get_rotation() const;
real_t get_skew() const;
void set_skew(real_t p_angle);
_FORCE_INLINE_ void set_rotation_and_scale(real_t p_rot, const Size2 &p_scale);
_FORCE_INLINE_ void set_rotation_scale_and_skew(real_t p_rot, const Size2 &p_scale, real_t p_skew);
void rotate(real_t p_angle);
void scale(const Size2 &p_scale);
void scale_basis(const Size2 &p_scale);
void translate_local(real_t p_tx, real_t p_ty);
void translate_local(const Vector2 &p_translation);
real_t determinant() const;
Size2 get_scale() const;
void set_scale(const Size2 &p_scale);
_FORCE_INLINE_ const Vector2 &get_origin() const { return columns[2]; }
_FORCE_INLINE_ void set_origin(const Vector2 &p_origin) { columns[2] = p_origin; }
Transform2D scaled(const Size2 &p_scale) const;
Transform2D scaled_local(const Size2 &p_scale) const;
Transform2D translated(const Vector2 &p_offset) const;
Transform2D translated_local(const Vector2 &p_offset) const;
Transform2D rotated(real_t p_angle) const;
Transform2D rotated_local(real_t p_angle) const;
Transform2D untranslated() const;
void orthonormalize();
Transform2D orthonormalized() const;
bool is_conformal() const;
bool is_equal_approx(const Transform2D &p_transform) const;
bool is_finite() const;
Transform2D looking_at(const Vector2 &p_target) const;
bool operator==(const Transform2D &p_transform) const;
bool operator!=(const Transform2D &p_transform) const;
void operator*=(const Transform2D &p_transform);
Transform2D operator*(const Transform2D &p_transform) const;
void operator*=(real_t p_val);
Transform2D operator*(real_t p_val) const;
void operator/=(real_t p_val);
Transform2D operator/(real_t p_val) const;
Transform2D interpolate_with(const Transform2D &p_transform, real_t p_c) const;
_FORCE_INLINE_ Vector2 basis_xform(const Vector2 &p_vec) const;
_FORCE_INLINE_ Vector2 basis_xform_inv(const Vector2 &p_vec) const;
_FORCE_INLINE_ Vector2 xform(const Vector2 &p_vec) const;
_FORCE_INLINE_ Vector2 xform_inv(const Vector2 &p_vec) const;
_FORCE_INLINE_ Rect2 xform(const Rect2 &p_rect) const;
_FORCE_INLINE_ Rect2 xform_inv(const Rect2 &p_rect) const;
_FORCE_INLINE_ Vector<Vector2> xform(const Vector<Vector2> &p_array) const;
_FORCE_INLINE_ Vector<Vector2> xform_inv(const Vector<Vector2> &p_array) const;
operator String() const;
Transform2D(real_t p_xx, real_t p_xy, real_t p_yx, real_t p_yy, real_t p_ox, real_t p_oy) {
columns[0][0] = p_xx;
columns[0][1] = p_xy;
columns[1][0] = p_yx;
columns[1][1] = p_yy;
columns[2][0] = p_ox;
columns[2][1] = p_oy;
}
Transform2D(const Vector2 &p_x, const Vector2 &p_y, const Vector2 &p_origin) {
columns[0] = p_x;
columns[1] = p_y;
columns[2] = p_origin;
}
Transform2D(real_t p_rot, const Vector2 &p_pos);
Transform2D(real_t p_rot, const Size2 &p_scale, real_t p_skew, const Vector2 &p_pos);
Transform2D() {
columns[0][0] = 1.0;
columns[1][1] = 1.0;
}
};
Vector2 Transform2D::basis_xform(const Vector2 &p_vec) const {
return Vector2(
tdotx(p_vec),
tdoty(p_vec));
}
Vector2 Transform2D::basis_xform_inv(const Vector2 &p_vec) const {
return Vector2(
columns[0].dot(p_vec),
columns[1].dot(p_vec));
}
Vector2 Transform2D::xform(const Vector2 &p_vec) const {
return Vector2(
tdotx(p_vec),
tdoty(p_vec)) +
columns[2];
}
Vector2 Transform2D::xform_inv(const Vector2 &p_vec) const {
Vector2 v = p_vec - columns[2];
return Vector2(
columns[0].dot(v),
columns[1].dot(v));
}
Rect2 Transform2D::xform(const Rect2 &p_rect) const {
Vector2 x = columns[0] * p_rect.size.x;
Vector2 y = columns[1] * p_rect.size.y;
Vector2 pos = xform(p_rect.position);
Rect2 new_rect;
new_rect.position = pos;
new_rect.expand_to(pos + x);
new_rect.expand_to(pos + y);
new_rect.expand_to(pos + x + y);
return new_rect;
}
void Transform2D::set_rotation_and_scale(real_t p_rot, const Size2 &p_scale) {
columns[0][0] = Math::cos(p_rot) * p_scale.x;
columns[1][1] = Math::cos(p_rot) * p_scale.y;
columns[1][0] = -Math::sin(p_rot) * p_scale.y;
columns[0][1] = Math::sin(p_rot) * p_scale.x;
}
void Transform2D::set_rotation_scale_and_skew(real_t p_rot, const Size2 &p_scale, real_t p_skew) {
columns[0][0] = Math::cos(p_rot) * p_scale.x;
columns[1][1] = Math::cos(p_rot + p_skew) * p_scale.y;
columns[1][0] = -Math::sin(p_rot + p_skew) * p_scale.y;
columns[0][1] = Math::sin(p_rot) * p_scale.x;
}
Rect2 Transform2D::xform_inv(const Rect2 &p_rect) const {
Vector2 ends[4] = {
xform_inv(p_rect.position),
xform_inv(Vector2(p_rect.position.x, p_rect.position.y + p_rect.size.y)),
xform_inv(Vector2(p_rect.position.x + p_rect.size.x, p_rect.position.y + p_rect.size.y)),
xform_inv(Vector2(p_rect.position.x + p_rect.size.x, p_rect.position.y))
};
Rect2 new_rect;
new_rect.position = ends[0];
new_rect.expand_to(ends[1]);
new_rect.expand_to(ends[2]);
new_rect.expand_to(ends[3]);
return new_rect;
}
Vector<Vector2> Transform2D::xform(const Vector<Vector2> &p_array) const {
Vector<Vector2> array;
array.resize(p_array.size());
const Vector2 *r = p_array.ptr();
Vector2 *w = array.ptrw();
for (int i = 0; i < p_array.size(); ++i) {
w[i] = xform(r[i]);
}
return array;
}
Vector<Vector2> Transform2D::xform_inv(const Vector<Vector2> &p_array) const {
Vector<Vector2> array;
array.resize(p_array.size());
const Vector2 *r = p_array.ptr();
Vector2 *w = array.ptrw();
for (int i = 0; i < p_array.size(); ++i) {
w[i] = xform_inv(r[i]);
}
return array;
}
#endif // TRANSFORM_2D_H