godot/servers/physics_2d/collision_solver_2d_sw.cpp
PouleyKetchoupp 829fb4fba1 Fix RayShape collision detection
One-way collision is disabled for both rigid bodies and character
bodies.

Kinematic margin is now applied to ray shapes to help getting consistent
results in slopes and flat surfaces.

Convex shapes don't return inverted normals when a segment test starts
inside (raycasting will be made consistent in a separate patch).

Ray shapes also discard contacts when fully contained inside a shape
and when the contact direction is inverted, so the behavior is
consistent with all shape types. Now they always separate only when
intersecting the top of a shape (for downward rays).
2021-08-24 16:03:05 -07:00

265 lines
9.9 KiB
C++

/*************************************************************************/
/* collision_solver_2d_sw.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2021 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_world_margin(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 WorldMarginShape2DSW *world_margin = static_cast<const WorldMarginShape2DSW *>(p_shape_A);
if (p_shape_B->get_type() == PhysicsServer2D::SHAPE_WORLD_MARGIN) {
return false;
}
Vector2 n = p_transform_A.basis_xform(world_margin->get_normal()).normalized();
Vector2 p = p_transform_A.xform(world_margin->get_normal() * world_margin->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 *r_sep_axis, real_t p_margin) {
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() + p_margin);
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 (r_sep_axis) {
*r_sep_axis = p_transform_A[1].normalized();
}
return false;
}
// Discard contacts when the ray is fully contained inside the shape.
if (n == Vector2()) {
if (r_sep_axis) {
*r_sep_axis = p_transform_A[1].normalized();
}
return false;
}
// Discard contacts in the wrong direction.
if (n.dot(from - to) < CMP_EPSILON) {
if (r_sep_axis) {
*r_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 *r_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 = r_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 *r_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_WORLD_MARGIN) {
if (type_B == PhysicsServer2D::SHAPE_WORLD_MARGIN) {
return false;
}
if (swap) {
return solve_static_world_margin(p_shape_B, p_transform_B, p_shape_A, p_transform_A, p_result_callback, p_userdata, true);
} else {
return solve_static_world_margin(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, r_sep_axis, p_margin_B);
} 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, r_sep_axis, p_margin_A);
}
} 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, r_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, r_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, r_sep_axis, margin_A, margin_B);
}
}