touchable::under_mouse flag impl

sources/enduro2d/high/systems/input_system.cpp

@@ -6,9 +6,209 @@
 
 #include <enduro2d/high/systems/input_system.hpp>
 
+#include <enduro2d/high/components/actor.hpp>
+#include <enduro2d/high/components/camera.hpp>
+#include <enduro2d/high/components/colliders.hpp>
+#include <enduro2d/high/components/disabled.hpp>
+#include <enduro2d/high/components/scene.hpp>
+#include <enduro2d/high/components/touchable.hpp>
+
+#include <enduro2d/high/gobject.hpp>
+#include <enduro2d/high/node.hpp>
+
+#define PNPOLY_IMPLEMENTATION
+#include <3rdparty/pnpoly.h/pnpoly.h>
+
 namespace
 {
     using namespace e2d;
+
+    struct world_space_rect_collider {
+        using src_collider_t = rect_collider;
+        std::array<v3f, 4> points{};
+    };
+
+    struct world_space_circle_collider {
+        using src_collider_t = circle_collider;
+        std::array<v3f, 12> points{};
+    };
+
+    struct world_space_polygon_collider {
+        using src_collider_t = polygon_collider;
+        vector<v3f> points{};
+    };
+
+    void update_world_space_collider(
+        world_space_rect_collider& dst,
+        const rect_collider& src,
+        const m4f& local_to_world)
+    {
+        const v2f& of = src.offset();
+        const v2f& hs = src.size() * 0.5f;
+
+        const v2f p1{of.x - hs.x, of.y - hs.y};
+        const v2f p2{of.x + hs.x, of.y - hs.y};
+        const v2f p3{of.x + hs.x, of.y + hs.y};
+        const v2f p4{of.x - hs.x, of.y + hs.y};
+
+        dst.points[0] = v3f(v4f(p1, 0.f, 1.f) * local_to_world);
+        dst.points[1] = v3f(v4f(p2, 0.f, 1.f) * local_to_world);
+        dst.points[2] = v3f(v4f(p3, 0.f, 1.f) * local_to_world);
+        dst.points[3] = v3f(v4f(p4, 0.f, 1.f) * local_to_world);
+    }
+
+    void update_world_space_collider(
+        world_space_circle_collider& dst,
+        const circle_collider& src,
+        const m4f& local_to_world)
+    {
+        const v2f& of = src.offset();
+        for ( std::size_t i = 0, e = dst.points.size(); i < e; ++i ) {
+            const radf a =
+                math::two_pi<f32>() /
+                math::numeric_cast<f32>(e) *
+                math::numeric_cast<f32>(i);
+            const v2f p =
+                of +
+                v2f(math::cos(a), math::sin(a)) *
+                src.radius();
+            dst.points[i] = v3f(v4f(p, 0.f, 1.f) * local_to_world);
+        }
+    }
+
+    void update_world_space_collider(
+        world_space_polygon_collider& dst,
+        const polygon_collider& src,
+        const m4f& local_to_world)
+    {
+        const vector<v2f>& src_points = src.points();
+
+        dst.points.clear();
+        if ( dst.points.capacity() < src_points.size() ) {
+            dst.points.reserve(math::max(dst.points.capacity() * 2u, src_points.size()));
+        }
+
+        const v2f& of = src.offset();
+        for ( std::size_t i = 0, e = src_points.size(); i < e; ++i ) {
+            const v2f p = of + src_points[i];
+            dst.points.push_back(v3f(v4f(p, 0.f, 1.f) * local_to_world));
+        }
+    }
+
+    template < typename WorldSpaceCollider >
+    void update_world_space_colliders(ecs::registry& owner) {
+        using dst_collider_t = WorldSpaceCollider;
+        using src_collider_t = typename WorldSpaceCollider::src_collider_t;
+        owner.for_joined_components<touchable, src_collider_t, actor>([](
+            ecs::entity e,
+            const touchable&,
+            const src_collider_t& src,
+            const actor& a)
+        {
+            update_world_space_collider(
+                e.ensure_component<dst_collider_t>(),
+                src,
+                a.node() ? a.node()->world_matrix() : m4f::identity());
+        }, !ecs::exists_any<disabled<touchable>, disabled<src_collider_t>>());
+    }
+}
+
+namespace
+{
+    using namespace e2d;
+
+    bool is_collider_under_mouse(
+        const world_space_rect_collider& c,
+        const v2f& mouse_p,
+        const m4f& camera_vp,
+        const b2f& camera_viewport) noexcept
+    {
+        std::array<
+            v2f,
+            std::tuple_size_v<decltype(c.points)>
+        > points;
+
+        std::transform(c.points.begin(), c.points.end(), points.begin(), [
+            &camera_vp,
+            &camera_viewport
+        ](const v3f& point) noexcept {
+            return v2f(math::project(point, camera_vp, camera_viewport).first);
+        });
+
+        return !!pnpoly_aos(
+            math::numeric_cast<int>(points.size()),
+            points.data()->data(),
+            mouse_p.x, mouse_p.y);
+    }
+
+    bool is_collider_under_mouse(
+        const world_space_circle_collider& c,
+        const v2f& mouse_p,
+        const m4f& camera_vp,
+        const b2f& camera_viewport) noexcept
+    {
+        std::array<
+            v2f,
+            std::tuple_size_v<decltype(c.points)>
+        > points;
+
+        std::transform(c.points.begin(), c.points.end(), points.begin(), [
+            &camera_vp,
+            &camera_viewport
+        ](const v3f& point) noexcept {
+            return v2f(math::project(point, camera_vp, camera_viewport).first);
+        });
+
+        return !!pnpoly_aos(
+            math::numeric_cast<int>(points.size()),
+            points.data()->data(),
+            mouse_p.x, mouse_p.y);
+    }
+
+    bool is_collider_under_mouse(
+        const world_space_polygon_collider& c,
+        const v2f& mouse_p,
+        const m4f& camera_vp,
+        const b2f& camera_viewport) noexcept
+    {
+        static thread_local std::vector<v2f> points;
+        points.clear();
+
+        if ( points.capacity() < c.points.size() ) {
+            points.reserve(math::max(points.capacity() * 2u, c.points.size()));
+        }
+
+        std::transform(c.points.begin(), c.points.end(), std::back_inserter(points), [
+            &camera_vp,
+            &camera_viewport
+        ](const v3f& point) noexcept {
+            return v2f(math::project(point, camera_vp, camera_viewport).first);
+        });
+
+        return !!pnpoly_aos(
+            math::numeric_cast<int>(points.size()),
+            points.data()->data(),
+            mouse_p.x, mouse_p.y);
+    }
+
+    template < typename WorldSpaceCollider >
+    void update_colliders_under_mouse(
+        ecs::registry& owner,
+        const v2f& mouse_p,
+        const m4f& camera_vp,
+        const b2f& camera_viewport)
+    {
+        using world_space_collider_t = WorldSpaceCollider;
+        owner.for_joined_components<touchable, world_space_collider_t>([
+            &mouse_p,
+            &camera_vp,
+            &camera_viewport
+        ](ecs::entity e, const touchable&, const world_space_collider_t& c){
+            if ( is_collider_under_mouse(c, mouse_p, camera_vp, camera_viewport) ) {
+                e.ensure_component<touchable::under_mouse>();
+            }
+        }, !ecs::exists_any<disabled<touchable>, disabled<world_space_collider_t>>());
+    }
 }
 
 namespace e2d
@@ -19,12 +219,67 @@ namespace e2d
 
     class input_system::internal_state final : private noncopyable {
     public:
-        internal_state() = default;
+        internal_state(input& i, window& w)
+        : input_(i)
+        , window_(w) {}
         ~internal_state() noexcept = default;
 
         void process_update(ecs::registry& owner) {
-            E2D_UNUSED(owner);
+            owner.remove_all_components<touchable::touched>();
+            owner.remove_all_components<touchable::under_mouse>();
+
+            update_world_space_colliders<world_space_rect_collider>(owner);
+            update_world_space_colliders<world_space_circle_collider>(owner);
+            update_world_space_colliders<world_space_polygon_collider>(owner);
+
+            owner.for_joined_components<camera::input, camera>([this, &owner](
+                const ecs::const_entity&,
+                const camera::input&,
+                const camera& camera)
+            {
+                const v2u& target_size = camera.target()
+                    ? camera.target()->size()
+                    : window_.framebuffer_size();
+
+                const v2f& mouse_p = math::normalized_to_point(
+                    b2f(target_size.cast_to<f32>()),
+                    math::point_to_normalized(
+                        b2f(window_.real_size().cast_to<f32>()),
+                        input_.mouse().cursor_pos()));
+
+                const m4f& camera_vp =
+                    camera.view() * camera.projection();
+
+                const b2f& camera_viewport = b2f(
+                    camera.viewport().position * target_size.cast_to<f32>(),
+                    camera.viewport().size * target_size.cast_to<f32>());
+
+                if ( !math::inside(camera_viewport, mouse_p) ) {
+                    return;
+                }
+
+                update_colliders_under_mouse<world_space_rect_collider>(
+                    owner,
+                    mouse_p,
+                    camera_vp,
+                    camera_viewport);
+
+                update_colliders_under_mouse<world_space_circle_collider>(
+                    owner,
+                    mouse_p,
+                    camera_vp,
+                    camera_viewport);
+
+                update_colliders_under_mouse<world_space_polygon_collider>(
+                    owner,
+                    mouse_p,
+                    camera_vp,
+                    camera_viewport);
+            }, !ecs::exists<disabled<camera>>());
         }
+    private:
+        input& input_;
+        window& window_;
     };
 
     //
@@ -32,7 +287,7 @@ namespace e2d
     //
 
     input_system::input_system()
-    : state_(new internal_state()) {}
+    : state_(new internal_state(the<input>(), the<window>())) {}
     input_system::~input_system() noexcept = default;
 
     void input_system::process(