godot/core/math/math_2d.cpp
Ferenc Arn 1a620bd5fa Made slide and reflect active verbs acting on itself in Vector2 and Vector3.
This is in alignment with other functions in vector classes.
Also added checks for normalization, fixed the sign of reflect (which now corresponds to reflection along a plane mathematically), added bounce method and updated docs.

Fixes #8201.
2017-04-03 10:02:12 -05:00

662 lines
15 KiB
C++

/*************************************************************************/
/* math_2d.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* http://www.godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/*************************************************************************/
#include "math_2d.h"
real_t Vector2::angle() const {
return Math::atan2(y, x);
}
real_t Vector2::length() const {
return Math::sqrt(x * x + y * y);
}
real_t Vector2::length_squared() const {
return x * x + y * y;
}
void Vector2::normalize() {
real_t l = x * x + y * y;
if (l != 0) {
l = Math::sqrt(l);
x /= l;
y /= l;
}
}
Vector2 Vector2::normalized() const {
Vector2 v = *this;
v.normalize();
return v;
}
bool Vector2::is_normalized() const {
return Math::isequal_approx(length(), (real_t)1.0);
}
real_t Vector2::distance_to(const Vector2 &p_vector2) const {
return Math::sqrt((x - p_vector2.x) * (x - p_vector2.x) + (y - p_vector2.y) * (y - p_vector2.y));
}
real_t Vector2::distance_squared_to(const Vector2 &p_vector2) const {
return (x - p_vector2.x) * (x - p_vector2.x) + (y - p_vector2.y) * (y - p_vector2.y);
}
real_t Vector2::angle_to(const Vector2 &p_vector2) const {
return Math::atan2(cross(p_vector2), dot(p_vector2));
}
real_t Vector2::angle_to_point(const Vector2 &p_vector2) const {
return Math::atan2(y - p_vector2.y, x - p_vector2.x);
}
real_t Vector2::dot(const Vector2 &p_other) const {
return x * p_other.x + y * p_other.y;
}
real_t Vector2::cross(const Vector2 &p_other) const {
return x * p_other.y - y * p_other.x;
}
Vector2 Vector2::cross(real_t p_other) const {
return Vector2(p_other * y, -p_other * x);
}
Vector2 Vector2::operator+(const Vector2 &p_v) const {
return Vector2(x + p_v.x, y + p_v.y);
}
void Vector2::operator+=(const Vector2 &p_v) {
x += p_v.x;
y += p_v.y;
}
Vector2 Vector2::operator-(const Vector2 &p_v) const {
return Vector2(x - p_v.x, y - p_v.y);
}
void Vector2::operator-=(const Vector2 &p_v) {
x -= p_v.x;
y -= p_v.y;
}
Vector2 Vector2::operator*(const Vector2 &p_v1) const {
return Vector2(x * p_v1.x, y * p_v1.y);
};
Vector2 Vector2::operator*(const real_t &rvalue) const {
return Vector2(x * rvalue, y * rvalue);
};
void Vector2::operator*=(const real_t &rvalue) {
x *= rvalue;
y *= rvalue;
};
Vector2 Vector2::operator/(const Vector2 &p_v1) const {
return Vector2(x / p_v1.x, y / p_v1.y);
};
Vector2 Vector2::operator/(const real_t &rvalue) const {
return Vector2(x / rvalue, y / rvalue);
};
void Vector2::operator/=(const real_t &rvalue) {
x /= rvalue;
y /= rvalue;
};
Vector2 Vector2::operator-() const {
return Vector2(-x, -y);
}
bool Vector2::operator==(const Vector2 &p_vec2) const {
return x == p_vec2.x && y == p_vec2.y;
}
bool Vector2::operator!=(const Vector2 &p_vec2) const {
return x != p_vec2.x || y != p_vec2.y;
}
Vector2 Vector2::floor() const {
return Vector2(Math::floor(x), Math::floor(y));
}
Vector2 Vector2::rotated(real_t p_by) const {
Vector2 v;
v.set_rotation(angle() + p_by);
v *= length();
return v;
}
Vector2 Vector2::project(const Vector2 &p_vec) const {
Vector2 v1 = p_vec;
Vector2 v2 = *this;
return v2 * (v1.dot(v2) / v2.dot(v2));
}
Vector2 Vector2::snapped(const Vector2 &p_by) const {
return Vector2(
Math::stepify(x, p_by.x),
Math::stepify(y, p_by.y));
}
Vector2 Vector2::clamped(real_t p_len) const {
real_t l = length();
Vector2 v = *this;
if (l > 0 && p_len < l) {
v /= l;
v *= p_len;
}
return v;
}
Vector2 Vector2::cubic_interpolate_soft(const Vector2 &p_b, const Vector2 &p_pre_a, const Vector2 &p_post_b, real_t p_t) const {
#if 0
k[0] = ((*this) (vi[0] + 1, vi[1], vi[2])) - ((*this) (vi[0],
vi[1],vi[2])); //fk = a0
k[1] = (((*this) (vi[0] + 1, vi[1], vi[2])) - ((*this) ((int) (v(0) -
1), vi[1],vi[2])))*0.5; //dk = a1
k[2] = (((*this) ((int) (v(0) + 2), vi[1], vi[2])) - ((*this) (vi[0],
vi[1],vi[2])))*0.5; //dk+1
k[3] = k[0]*3 - k[1]*2 - k[2];//a2
k[4] = k[1] + k[2] - k[0]*2;//a3
//ip = a3(t-tk)³ + a2(t-tk)² + a1(t-tk) + a0
//
//a3 = dk + dk+1 - Dk
//a2 = 3Dk - 2dk - dk+1
//a1 = dk
//a0 = fk
//
//dk = (fk+1 - fk-1)*0.5
//Dk = (fk+1 - fk)
real_t dk =
#endif
return Vector2();
}
Vector2 Vector2::cubic_interpolate(const Vector2 &p_b, const Vector2 &p_pre_a, const Vector2 &p_post_b, real_t p_t) const {
Vector2 p0 = p_pre_a;
Vector2 p1 = *this;
Vector2 p2 = p_b;
Vector2 p3 = p_post_b;
real_t t = p_t;
real_t t2 = t * t;
real_t t3 = t2 * t;
Vector2 out;
out = 0.5 * ((p1 * 2.0) +
(-p0 + p2) * t +
(2.0 * p0 - 5.0 * p1 + 4 * p2 - p3) * t2 +
(-p0 + 3.0 * p1 - 3.0 * p2 + p3) * t3);
return out;
/*
real_t mu = p_t;
real_t mu2 = mu*mu;
Vector2 a0 = p_post_b - p_b - p_pre_a + *this;
Vector2 a1 = p_pre_a - *this - a0;
Vector2 a2 = p_b - p_pre_a;
Vector2 a3 = *this;
return ( a0*mu*mu2 + a1*mu2 + a2*mu + a3 );
*/
/*
real_t t = p_t;
real_t t2 = t*t;
real_t t3 = t2*t;
real_t a = 2.0*t3- 3.0*t2 + 1;
real_t b = -2.0*t3+ 3.0*t2;
real_t c = t3- 2.0*t2 + t;
real_t d = t3- t2;
Vector2 p_a=*this;
return Vector2(
(a * p_a.x) + (b *p_b.x) + (c * p_pre_a.x) + (d * p_post_b.x),
(a * p_a.y) + (b *p_b.y) + (c * p_pre_a.y) + (d * p_post_b.y)
);
*/
}
// slide returns the component of the vector along the given plane, specified by its normal vector.
Vector2 Vector2::slide(const Vector2 &p_n) const {
#ifdef DEBUG_ENABLED
ERR_FAIL_COND_V(p_n.is_normalized() == false, Vector2());
#endif
return *this - p_n * this->dot(p_n);
}
Vector2 Vector2::bounce(const Vector2 &p_n) const {
return -reflect(p_n);
}
Vector2 Vector2::reflect(const Vector2 &p_n) const {
#ifdef DEBUG_ENABLED
ERR_FAIL_COND_V(p_n.is_normalized() == false, Vector2());
#endif
return 2.0 * p_n * this->dot(p_n) - *this;
}
bool Rect2::intersects_segment(const Point2 &p_from, const Point2 &p_to, Point2 *r_pos, Point2 *r_normal) const {
real_t min = 0, max = 1;
int axis = 0;
real_t sign = 0;
for (int i = 0; i < 2; i++) {
real_t seg_from = p_from[i];
real_t seg_to = p_to[i];
real_t box_begin = pos[i];
real_t box_end = box_begin + size[i];
real_t cmin, cmax;
real_t csign;
if (seg_from < seg_to) {
if (seg_from > box_end || seg_to < box_begin)
return false;
real_t length = seg_to - seg_from;
cmin = (seg_from < box_begin) ? ((box_begin - seg_from) / length) : 0;
cmax = (seg_to > box_end) ? ((box_end - seg_from) / length) : 1;
csign = -1.0;
} else {
if (seg_to > box_end || seg_from < box_begin)
return false;
real_t length = seg_to - seg_from;
cmin = (seg_from > box_end) ? (box_end - seg_from) / length : 0;
cmax = (seg_to < box_begin) ? (box_begin - seg_from) / length : 1;
csign = 1.0;
}
if (cmin > min) {
min = cmin;
axis = i;
sign = csign;
}
if (cmax < max)
max = cmax;
if (max < min)
return false;
}
Vector2 rel = p_to - p_from;
if (r_normal) {
Vector2 normal;
normal[axis] = sign;
*r_normal = normal;
}
if (r_pos)
*r_pos = p_from + rel * min;
return true;
}
/* Point2i */
Point2i Point2i::operator+(const Point2i &p_v) const {
return Point2i(x + p_v.x, y + p_v.y);
}
void Point2i::operator+=(const Point2i &p_v) {
x += p_v.x;
y += p_v.y;
}
Point2i Point2i::operator-(const Point2i &p_v) const {
return Point2i(x - p_v.x, y - p_v.y);
}
void Point2i::operator-=(const Point2i &p_v) {
x -= p_v.x;
y -= p_v.y;
}
Point2i Point2i::operator*(const Point2i &p_v1) const {
return Point2i(x * p_v1.x, y * p_v1.y);
};
Point2i Point2i::operator*(const int &rvalue) const {
return Point2i(x * rvalue, y * rvalue);
};
void Point2i::operator*=(const int &rvalue) {
x *= rvalue;
y *= rvalue;
};
Point2i Point2i::operator/(const Point2i &p_v1) const {
return Point2i(x / p_v1.x, y / p_v1.y);
};
Point2i Point2i::operator/(const int &rvalue) const {
return Point2i(x / rvalue, y / rvalue);
};
void Point2i::operator/=(const int &rvalue) {
x /= rvalue;
y /= rvalue;
};
Point2i Point2i::operator-() const {
return Point2i(-x, -y);
}
bool Point2i::operator==(const Point2i &p_vec2) const {
return x == p_vec2.x && y == p_vec2.y;
}
bool Point2i::operator!=(const Point2i &p_vec2) const {
return x != p_vec2.x || y != p_vec2.y;
}
void Transform2D::invert() {
// FIXME: this function assumes the basis is a rotation matrix, with no scaling.
// Transform2D::affine_inverse can handle matrices with scaling, so GDScript should eventually use that.
SWAP(elements[0][1], elements[1][0]);
elements[2] = basis_xform(-elements[2]);
}
Transform2D Transform2D::inverse() const {
Transform2D inv = *this;
inv.invert();
return inv;
}
void Transform2D::affine_invert() {
real_t det = basis_determinant();
ERR_FAIL_COND(det == 0);
real_t idet = 1.0 / det;
SWAP(elements[0][0], elements[1][1]);
elements[0] *= Vector2(idet, -idet);
elements[1] *= Vector2(-idet, idet);
elements[2] = basis_xform(-elements[2]);
}
Transform2D Transform2D::affine_inverse() const {
Transform2D inv = *this;
inv.affine_invert();
return inv;
}
void Transform2D::rotate(real_t p_phi) {
*this = Transform2D(p_phi, Vector2()) * (*this);
}
real_t Transform2D::get_rotation() const {
real_t det = basis_determinant();
Transform2D m = orthonormalized();
if (det < 0) {
m.scale_basis(Size2(1, -1)); // convention to separate rotation and reflection for 2D is to absorb a flip along y into scaling.
}
return Math::atan2(m[0].y, m[0].x);
}
void Transform2D::set_rotation(real_t p_rot) {
real_t cr = Math::cos(p_rot);
real_t sr = Math::sin(p_rot);
elements[0][0] = cr;
elements[0][1] = sr;
elements[1][0] = -sr;
elements[1][1] = cr;
}
Transform2D::Transform2D(real_t p_rot, const Vector2 &p_pos) {
real_t cr = Math::cos(p_rot);
real_t sr = Math::sin(p_rot);
elements[0][0] = cr;
elements[0][1] = sr;
elements[1][0] = -sr;
elements[1][1] = cr;
elements[2] = p_pos;
}
Size2 Transform2D::get_scale() const {
real_t det_sign = basis_determinant() > 0 ? 1 : -1;
return Size2(elements[0].length(), det_sign * elements[1].length());
}
void Transform2D::scale(const Size2 &p_scale) {
scale_basis(p_scale);
elements[2] *= p_scale;
}
void Transform2D::scale_basis(const Size2 &p_scale) {
elements[0][0] *= p_scale.x;
elements[0][1] *= p_scale.y;
elements[1][0] *= p_scale.x;
elements[1][1] *= p_scale.y;
}
void Transform2D::translate(real_t p_tx, real_t p_ty) {
translate(Vector2(p_tx, p_ty));
}
void Transform2D::translate(const Vector2 &p_translation) {
elements[2] += basis_xform(p_translation);
}
void Transform2D::orthonormalize() {
// Gram-Schmidt Process
Vector2 x = elements[0];
Vector2 y = elements[1];
x.normalize();
y = (y - x * (x.dot(y)));
y.normalize();
elements[0] = x;
elements[1] = y;
}
Transform2D Transform2D::orthonormalized() const {
Transform2D on = *this;
on.orthonormalize();
return on;
}
bool Transform2D::operator==(const Transform2D &p_transform) const {
for (int i = 0; i < 3; i++) {
if (elements[i] != p_transform.elements[i])
return false;
}
return true;
}
bool Transform2D::operator!=(const Transform2D &p_transform) const {
for (int i = 0; i < 3; i++) {
if (elements[i] != p_transform.elements[i])
return true;
}
return false;
}
void Transform2D::operator*=(const Transform2D &p_transform) {
elements[2] = xform(p_transform.elements[2]);
real_t x0, x1, y0, y1;
x0 = tdotx(p_transform.elements[0]);
x1 = tdoty(p_transform.elements[0]);
y0 = tdotx(p_transform.elements[1]);
y1 = tdoty(p_transform.elements[1]);
elements[0][0] = x0;
elements[0][1] = x1;
elements[1][0] = y0;
elements[1][1] = y1;
}
Transform2D Transform2D::operator*(const Transform2D &p_transform) const {
Transform2D t = *this;
t *= p_transform;
return t;
}
Transform2D Transform2D::scaled(const Size2 &p_scale) const {
Transform2D copy = *this;
copy.scale(p_scale);
return copy;
}
Transform2D Transform2D::basis_scaled(const Size2 &p_scale) const {
Transform2D copy = *this;
copy.scale_basis(p_scale);
return copy;
}
Transform2D Transform2D::untranslated() const {
Transform2D copy = *this;
copy.elements[2] = Vector2();
return copy;
}
Transform2D Transform2D::translated(const Vector2 &p_offset) const {
Transform2D copy = *this;
copy.translate(p_offset);
return copy;
}
Transform2D Transform2D::rotated(real_t p_phi) const {
Transform2D copy = *this;
copy.rotate(p_phi);
return copy;
}
real_t Transform2D::basis_determinant() const {
return elements[0].x * elements[1].y - elements[0].y * elements[1].x;
}
Transform2D Transform2D::interpolate_with(const Transform2D &p_transform, real_t p_c) const {
//extract parameters
Vector2 p1 = get_origin();
Vector2 p2 = p_transform.get_origin();
real_t r1 = get_rotation();
real_t r2 = p_transform.get_rotation();
Size2 s1 = get_scale();
Size2 s2 = p_transform.get_scale();
//slerp rotation
Vector2 v1(Math::cos(r1), Math::sin(r1));
Vector2 v2(Math::cos(r2), Math::sin(r2));
real_t dot = v1.dot(v2);
dot = (dot < -1.0) ? -1.0 : ((dot > 1.0) ? 1.0 : dot); //clamp dot to [-1,1]
Vector2 v;
if (dot > 0.9995) {
v = Vector2::linear_interpolate(v1, v2, p_c).normalized(); //linearly interpolate to avoid numerical precision issues
} else {
real_t angle = p_c * Math::acos(dot);
Vector2 v3 = (v2 - v1 * dot).normalized();
v = v1 * Math::cos(angle) + v3 * Math::sin(angle);
}
//construct matrix
Transform2D res(Math::atan2(v.y, v.x), Vector2::linear_interpolate(p1, p2, p_c));
res.scale_basis(Vector2::linear_interpolate(s1, s2, p_c));
return res;
}
Transform2D::operator String() const {
return String(String() + elements[0] + ", " + elements[1] + ", " + elements[2]);
}