fix: playerinput mouse events now report correctly

player_input.cpp

@@ -4,10 +4,14 @@
 #include "godot_cpp/classes/input_event.hpp"
 #include "godot_cpp/classes/input_event_mouse_motion.hpp"
 #include <algorithm>
+#include <optional>
 
 namespace godot {
 void PlayerInput::_bind_methods() {}
 
+Vector2 PlayerInput::lastMouseMotion{0.f, 0.f};
+bool PlayerInput::primaryExists{false};
+
 PlayerInput::Listener::Listener(String positive, String negative, Node *object, String method)
 : actionNegative{negative}
 , actionPositive{positive}
@@ -15,40 +19,45 @@ PlayerInput::Listener::Listener(String positive, String negative, Node *object,
 , object{object}
 , isMouseEvent{positive.begins_with("_mouse_") || negative.begins_with("_mouse_")} {}
 
-float PlayerInput::Listener::evaluate_event(Ref<InputEvent> const &event, String const &action) {
+std::optional<float> PlayerInput::Listener::evaluate_action(String const &action) {
     Input *input = Input::get_singleton();
-    if(!action.begins_with("_mouse_")) {
-        return float(input->is_action_pressed(action));
+    if(action.begins_with("_mouse_")) {
+        Vector2 vector = PlayerInput::get_last_mouse_motion();
+        if(action.ends_with("_up"))
+            return vector.y > 0.f ? vector.y : 0.f;
+        else if(action.ends_with("_down"))
+            return vector.y < 0.f ? -vector.y : 0.f;
+        else if(action.ends_with("_right"))
+            return vector.x > 0.f ? vector.x : 0.f;
+        else if(action.ends_with("_left"))
+            return vector.x < 0.f ? -vector.x : 0.f;
+        else
+            return std::nullopt;
+    } else if(action.is_empty()) {
+        return 0.f;
     } else {
-        InputEventMouseMotion *motion = Object::cast_to<InputEventMouseMotion>(*event);
-        if(motion == nullptr)
-            return 0.f;
-        if(action.ends_with("_up") || action.ends_with("_right")) {
-            return motion->get_relative().x;
-        } if(action.ends_with("_right") || action.ends_with("_left")) {
-            return motion->get_relative().y;
-        }
+        return float(input->is_action_pressed(action));
     }
-    return 0.f;
 }
 
 bool PlayerInput::Listener::has_changed(Ref<InputEvent> const &event) {
     return (
         (!event->is_class("InputEventMouseMotion") ||
-            this->isMouseEvent
-        ) ||
+            this->isMouseEvent) ||
         event->is_action(this->actionNegative) ||
         event->is_action(this->actionPositive)
     );
 }
 
 float PlayerInput::Listener::evaluate(Ref<InputEvent> const &event) {
-    float positive = PlayerInput::Listener::evaluate_event(event, this->actionPositive);
-    float negative = PlayerInput::Listener::evaluate_event(event, this->actionNegative);
-    float newest = positive - negative;
-    if(lastCached != newest)
+    std::optional<float> positive = PlayerInput::Listener::evaluate_action(this->actionPositive);
+    std::optional<float> negative = PlayerInput::Listener::evaluate_action(this->actionNegative);
+    if(!positive.has_value() || !negative.has_value())
+        return 0.f;
+    float newest = positive.value() - negative.value();
+    if(this->lastCached != newest || this->isMouseEvent)
         this->object->call(this->methodName, event, newest);
-    return (lastCached = newest);
+    return (this->lastCached = newest);
 }
 
 bool PlayerInput::Listener::operator==(godot::PlayerInput::Listener const& b) {
@@ -58,8 +67,30 @@ bool PlayerInput::Listener::operator==(godot::PlayerInput::Listener const& b) {
         && this->actionPositive == b.actionPositive;
 }
 
+Vector2 PlayerInput::get_last_mouse_motion() {
+    return PlayerInput::lastMouseMotion;
+}
+
+void PlayerInput::_enter_tree() {
+    GDGAMEONLY();
+    if(!PlayerInput::primaryExists) {
+        this->isPrimary = true;
+        PlayerInput::primaryExists = true;
+    }
+}
+
+void PlayerInput::_exit_tree() {
+    GDGAMEONLY();
+    if(this->isPrimary) {
+        this->isPrimary = false;
+        PlayerInput::primaryExists = false;
+    }
+}
+
 void PlayerInput::_unhandled_input(Ref<InputEvent> const &event) {
     GDGAMEONLY();
+    if(this->isPrimary && event->is_class("InputEventMouseMotion"))
+        PlayerInput::lastMouseMotion = Object::cast_to<InputEventMouseMotion>(*event)->get_relative();
     for(Listener& listener: this->listeners) {
         if(listener.has_changed(event)) {
             listener.evaluate(event);
@@ -67,6 +98,10 @@ void PlayerInput::_unhandled_input(Ref<InputEvent> const &event) {
     }
 }
 
+void PlayerInput::_process(double deltaTime) {
+    PlayerInput::lastMouseMotion = {0.f, 0.f};
+}
+
 void PlayerInput::listen_to(Listener const& listener) {
     this->listeners.push_back(listener);
 }

player_input.hpp

@@ -2,6 +2,7 @@
 #define PLAYER_INPUT_HPP
 
 #include <vector>
+#include <optional>
 #include "godot_cpp/classes/input.hpp"
 #include "godot_cpp/classes/input_event.hpp"
 #include "godot_cpp/classes/node.hpp"
@@ -11,27 +12,61 @@ class PlayerInput : public Node {
     GDCLASS(PlayerInput, Node)
     static void _bind_methods();
 public:
+    // a listener is a combination of a positive and negative action and a listener function.
+    // listener functions use godot's Object::call function.
+    // So they require a Node instance and a function name.
+    // The expected signature is void(Ref<InputEvent>, float)
+    // actions can also be "special" actions prefixed with _.
+    // special actions include _mouse_up, _mouse_down, _mouse_left and _mouse_right
+    // which rather than checking action_is_down,
+    // will use PlayerInput::get_last_mouse_motion() to poll the current state.
     struct Listener {
         friend class PlayerInput;
     private:
+        // the two actions, evaluated as positive - negative
         String actionNegative{""};
         String actionPositive{""};
+        // the last cached action, if the newest result matches this, the event will be considered
+        // duplicate and ignored (not passed to listener)
         float lastCached{0.f};
+        // name of the method to call, expected signature is void(Ref<InputEvent>, float)
         String methodName{""};
+        // pointer to the node to call methodName on
         Node *object{nullptr};
+        // if either actionNegative or actionPositive is a _mouse_ event this will be true
         bool isMouseEvent{false};
 
     public:
         Listener(String positive, String negative, Node *object, String method);
-        static float evaluate_event(Ref<InputEvent> const &event, String const &action);
+        // evaluate the current state of an action.
+        static std::optional<float> evaluate_action(String const &action);
+        // check if this event has any chance to result in a trigger, does not evaluate the event or
+        // poll current input state
         bool has_changed(Ref<InputEvent> const &event);
+        // evaluate the event for changes to either actionPositive or actionNegative
         float evaluate(Ref<InputEvent> const &event);
+
         bool operator==(godot::PlayerInput::Listener const& b);
     };
 private:
+    // the last mouse motion, updated by the primary instance
+    static Vector2 lastMouseMotion;
+    // does a primary instance exist
+    static bool primaryExists;
+    // is this the primary instance
+    // the primary instance is responsible for updating static
+    // variables like lastMouseMotion
+    bool isPrimary{false};
+
+    // current listeners for this instance
     std::vector<Listener> listeners{};
 public:
+    static Vector2 get_last_mouse_motion();
+
+    virtual void _enter_tree() override;
+    virtual void _exit_tree() override;
     virtual void _unhandled_input(Ref<InputEvent> const &event) override;
+    virtual void _process(double deltaTime) override;
 
     void listen_to(Listener const& listener);
     void stop_listening(Node *node);