godot/servers/physics_2d/collision_solver_2d_sw.cpp
Marcel Admiraal 7e44682c03 Fix how Line2D obtains the other object's supports
Measure the distance from the line against the rotated object, not the
rotated line, when obtaining the object's supports against a line.
2020-10-03 12:59:34 +01:00

249 lines
9.4 KiB
C++

/*************************************************************************/
/* collision_solver_2d_sw.cpp */
/*************************************************************************/
/* This file is part of: */
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md). */
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#include "collision_solver_2d_sw.h"
#include "collision_solver_2d_sat.h"
#define collision_solver sat_2d_calculate_penetration
//#define collision_solver gjk_epa_calculate_penetration
bool CollisionSolver2DSW::solve_static_line(const Shape2DSW *p_shape_A, const Transform2D &p_transform_A, const Shape2DSW *p_shape_B, const Transform2D &p_transform_B, CallbackResult p_result_callback, void *p_userdata, bool p_swap_result) {
const LineShape2DSW *line = static_cast<const LineShape2DSW *>(p_shape_A);
if (p_shape_B->get_type() == PhysicsServer2D::SHAPE_LINE) {
return false;
}
Vector2 n = p_transform_A.basis_xform(line->get_normal()).normalized();
Vector2 p = p_transform_A.xform(line->get_normal() * line->get_d());
real_t d = n.dot(p);
Vector2 supports[2];
int support_count;
p_shape_B->get_supports(p_transform_B.affine_inverse().basis_xform(-n).normalized(), supports, support_count);
bool found = false;
for (int i = 0; i < support_count; i++) {
supports[i] = p_transform_B.xform(supports[i]);
real_t pd = n.dot(supports[i]);
if (pd >= d) {
continue;
}
found = true;
Vector2 support_A = supports[i] - n * (pd - d);
if (p_result_callback) {
if (p_swap_result) {
p_result_callback(supports[i], support_A, p_userdata);
} else {
p_result_callback(support_A, supports[i], p_userdata);
}
}
}
return found;
}
bool CollisionSolver2DSW::solve_raycast(const Shape2DSW *p_shape_A, const Vector2 &p_motion_A, const Transform2D &p_transform_A, const Shape2DSW *p_shape_B, const Transform2D &p_transform_B, CallbackResult p_result_callback, void *p_userdata, bool p_swap_result, Vector2 *sep_axis) {
const RayShape2DSW *ray = static_cast<const RayShape2DSW *>(p_shape_A);
if (p_shape_B->get_type() == PhysicsServer2D::SHAPE_RAY) {
return false;
}
Vector2 from = p_transform_A.get_origin();
Vector2 to = from + p_transform_A[1] * ray->get_length();
if (p_motion_A != Vector2()) {
//not the best but should be enough
Vector2 normal = (to - from).normalized();
to += normal * MAX(0.0, normal.dot(p_motion_A));
}
Vector2 support_A = to;
Transform2D invb = p_transform_B.affine_inverse();
from = invb.xform(from);
to = invb.xform(to);
Vector2 p, n;
if (!p_shape_B->intersect_segment(from, to, p, n)) {
if (sep_axis) {
*sep_axis = p_transform_A[1].normalized();
}
return false;
}
Vector2 support_B = p_transform_B.xform(p);
if (ray->get_slips_on_slope()) {
Vector2 global_n = invb.basis_xform_inv(n).normalized();
support_B = support_A + (support_B - support_A).length() * global_n;
}
if (p_result_callback) {
if (p_swap_result) {
p_result_callback(support_B, support_A, p_userdata);
} else {
p_result_callback(support_A, support_B, p_userdata);
}
}
return true;
}
struct _ConcaveCollisionInfo2D {
const Transform2D *transform_A;
const Shape2DSW *shape_A;
const Transform2D *transform_B;
Vector2 motion_A;
Vector2 motion_B;
real_t margin_A;
real_t margin_B;
CollisionSolver2DSW::CallbackResult result_callback;
void *userdata;
bool swap_result;
bool collided;
int aabb_tests;
int collisions;
Vector2 *sep_axis;
};
void CollisionSolver2DSW::concave_callback(void *p_userdata, Shape2DSW *p_convex) {
_ConcaveCollisionInfo2D &cinfo = *(_ConcaveCollisionInfo2D *)(p_userdata);
cinfo.aabb_tests++;
if (!cinfo.result_callback && cinfo.collided) {
return; //already collided and no contacts requested, don't test anymore
}
bool collided = collision_solver(cinfo.shape_A, *cinfo.transform_A, cinfo.motion_A, p_convex, *cinfo.transform_B, cinfo.motion_B, cinfo.result_callback, cinfo.userdata, cinfo.swap_result, cinfo.sep_axis, cinfo.margin_A, cinfo.margin_B);
if (!collided) {
return;
}
cinfo.collided = true;
cinfo.collisions++;
}
bool CollisionSolver2DSW::solve_concave(const Shape2DSW *p_shape_A, const Transform2D &p_transform_A, const Vector2 &p_motion_A, const Shape2DSW *p_shape_B, const Transform2D &p_transform_B, const Vector2 &p_motion_B, CallbackResult p_result_callback, void *p_userdata, bool p_swap_result, Vector2 *sep_axis, real_t p_margin_A, real_t p_margin_B) {
const ConcaveShape2DSW *concave_B = static_cast<const ConcaveShape2DSW *>(p_shape_B);
_ConcaveCollisionInfo2D cinfo;
cinfo.transform_A = &p_transform_A;
cinfo.shape_A = p_shape_A;
cinfo.transform_B = &p_transform_B;
cinfo.motion_A = p_motion_A;
cinfo.result_callback = p_result_callback;
cinfo.userdata = p_userdata;
cinfo.swap_result = p_swap_result;
cinfo.collided = false;
cinfo.collisions = 0;
cinfo.sep_axis = sep_axis;
cinfo.margin_A = p_margin_A;
cinfo.margin_B = p_margin_B;
cinfo.aabb_tests = 0;
Transform2D rel_transform = p_transform_A;
rel_transform.elements[2] -= p_transform_B.get_origin();
//quickly compute a local Rect2
Rect2 local_aabb;
for (int i = 0; i < 2; i++) {
Vector2 axis(p_transform_B.elements[i]);
real_t axis_scale = 1.0 / axis.length();
axis *= axis_scale;
real_t smin, smax;
p_shape_A->project_rangev(axis, rel_transform, smin, smax);
smin *= axis_scale;
smax *= axis_scale;
local_aabb.position[i] = smin;
local_aabb.size[i] = smax - smin;
}
concave_B->cull(local_aabb, concave_callback, &cinfo);
return cinfo.collided;
}
bool CollisionSolver2DSW::solve(const Shape2DSW *p_shape_A, const Transform2D &p_transform_A, const Vector2 &p_motion_A, const Shape2DSW *p_shape_B, const Transform2D &p_transform_B, const Vector2 &p_motion_B, CallbackResult p_result_callback, void *p_userdata, Vector2 *sep_axis, real_t p_margin_A, real_t p_margin_B) {
PhysicsServer2D::ShapeType type_A = p_shape_A->get_type();
PhysicsServer2D::ShapeType type_B = p_shape_B->get_type();
bool concave_A = p_shape_A->is_concave();
bool concave_B = p_shape_B->is_concave();
real_t margin_A = p_margin_A, margin_B = p_margin_B;
bool swap = false;
if (type_A > type_B) {
SWAP(type_A, type_B);
SWAP(concave_A, concave_B);
SWAP(margin_A, margin_B);
swap = true;
}
if (type_A == PhysicsServer2D::SHAPE_LINE) {
if (type_B == PhysicsServer2D::SHAPE_LINE || type_B == PhysicsServer2D::SHAPE_RAY) {
return false;
}
if (swap) {
return solve_static_line(p_shape_B, p_transform_B, p_shape_A, p_transform_A, p_result_callback, p_userdata, true);
} else {
return solve_static_line(p_shape_A, p_transform_A, p_shape_B, p_transform_B, p_result_callback, p_userdata, false);
}
} else if (type_A == PhysicsServer2D::SHAPE_RAY) {
if (type_B == PhysicsServer2D::SHAPE_RAY) {
return false; //no ray-ray
}
if (swap) {
return solve_raycast(p_shape_B, p_motion_B, p_transform_B, p_shape_A, p_transform_A, p_result_callback, p_userdata, true, sep_axis);
} else {
return solve_raycast(p_shape_A, p_motion_A, p_transform_A, p_shape_B, p_transform_B, p_result_callback, p_userdata, false, sep_axis);
}
} else if (concave_B) {
if (concave_A) {
return false;
}
if (!swap) {
return solve_concave(p_shape_A, p_transform_A, p_motion_A, p_shape_B, p_transform_B, p_motion_B, p_result_callback, p_userdata, false, sep_axis, margin_A, margin_B);
} else {
return solve_concave(p_shape_B, p_transform_B, p_motion_B, p_shape_A, p_transform_A, p_motion_A, p_result_callback, p_userdata, true, sep_axis, margin_A, margin_B);
}
} else {
return collision_solver(p_shape_A, p_transform_A, p_motion_A, p_shape_B, p_transform_B, p_motion_B, p_result_callback, p_userdata, false, sep_axis, margin_A, margin_B);
}
}