💿🐜 Antkeeper source code
https://antkeeper.com
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122 lines
3.6 KiB
122 lines
3.6 KiB
/*
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* Copyright (C) 2023 Christopher J. Howard
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*
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* This file is part of Antkeeper source code.
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*
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* Antkeeper source code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Antkeeper source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "game/systems/collision-system.hpp"
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#include "game/components/transform-component.hpp"
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#include "game/components/picking-component.hpp"
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#include "game/components/rigid-body-component.hpp"
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#include <engine/geom/intersection.hpp>
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#include <engine/geom/primitives/plane.hpp>
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#include <engine/math/transform-operators.hpp>
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#include <limits>
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collision_system::collision_system(entity::registry& registry):
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updatable_system(registry)
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{
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}
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collision_system::~collision_system()
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{
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}
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void collision_system::update(float t, float dt)
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{
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}
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entity::id collision_system::pick_nearest(const geom::ray<float, 3>& ray, std::uint32_t flags) const
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{
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entity::id nearest_eid = entt::null;
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float nearest_distance = std::numeric_limits<float>::infinity();
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// For each entity with picking and transform components
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registry.view<picking_component, transform_component>().each
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(
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[&](entity::id entity_id, const auto& picking, const auto& transform)
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{
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// Skip entity if picking flags don't match
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if (!~(flags | picking.flags))
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return;
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// Transform picking sphere
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const geom::sphere<float> sphere =
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{
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transform.world * picking.sphere.center,
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picking.sphere.radius * math::max(transform.world.scale)
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};
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// Test for intersection between ray and sphere
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auto result = geom::intersection(ray, sphere);
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if (result)
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{
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float t0 = std::get<0>(*result);
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float t1 = std::get<1>(*result);
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if (t0 < nearest_distance)
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{
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nearest_eid = entity_id;
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nearest_distance = t0;
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}
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}
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}
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);
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return nearest_eid;
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}
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entity::id collision_system::pick_nearest(const math::vector<float, 3>& origin, const math::vector<float, 3>& normal, std::uint32_t flags) const
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{
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entity::id nearest_eid = entt::null;
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float nearest_sqr_distance = std::numeric_limits<float>::infinity();
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// Construct picking plane
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const geom::plane<float> picking_plane = geom::plane<float>(origin, normal);
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// For each entity with picking and transform components
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registry.view<picking_component, transform_component>().each
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(
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[&](entity::id entity_id, const auto& picking, const auto& transform)
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{
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// Skip entity if picking flags don't match
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if (!~(flags | picking.flags))
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return;
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// Transform picking sphere center
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math::vector<float, 3> picking_sphere_center = transform.world * picking.sphere.center;
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// Skip entity if picking sphere center has negative distance from picking plane
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if (picking_plane.distance(picking_sphere_center) < 0.0f)
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return;
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// Measure distance from picking plane origin to picking sphere center
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const float sqr_distance = math::sqr_distance(picking_sphere_center, origin);
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// Check if entity is nearer than the current nearest entity
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if (sqr_distance < nearest_sqr_distance)
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{
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nearest_eid = entity_id;
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nearest_sqr_distance = sqr_distance;
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}
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}
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);
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return nearest_eid;
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}
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