1 files changed, 270 insertions, 0 deletions

diff --git a/src/input_common/helpers/stick_from_buttons.cpp b/src/input_common/helpers/stick_from_buttons.cpp
new file mode 100644
index 000000000..38f150746
--- /dev/null
+++ b/src/input_common/helpers/stick_from_buttons.cpp
@@ -0,0 +1,270 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <chrono>
+#include <cmath>
+#include "common/math_util.h"
+#include "common/settings.h"
+#include "input_common/helpers/stick_from_buttons.h"
+
+namespace InputCommon {
+
+class Stick final : public Input::InputDevice {
+public:
+    using Button = std::unique_ptr<Input::InputDevice>;
+
+    Stick(Button up_, Button down_, Button left_, Button right_, Button modifier_,
+          float modifier_scale_, float modifier_angle_)
+        : up(std::move(up_)), down(std::move(down_)), left(std::move(left_)),
+          right(std::move(right_)), modifier(std::move(modifier_)), modifier_scale(modifier_scale_),
+          modifier_angle(modifier_angle_) {
+        Input::InputCallback button_up_callback{
+            [this](Input::CallbackStatus callback_) { UpdateUpButtonStatus(callback_); }};
+        Input::InputCallback button_down_callback{
+            [this](Input::CallbackStatus callback_) { UpdateDownButtonStatus(callback_); }};
+        Input::InputCallback button_left_callback{
+            [this](Input::CallbackStatus callback_) { UpdateLeftButtonStatus(callback_); }};
+        Input::InputCallback button_right_callback{
+            [this](Input::CallbackStatus callback_) { UpdateRightButtonStatus(callback_); }};
+        Input::InputCallback button_modifier_callback{
+            [this](Input::CallbackStatus callback_) { UpdateModButtonStatus(callback_); }};
+        up->SetCallback(button_up_callback);
+        down->SetCallback(button_down_callback);
+        left->SetCallback(button_left_callback);
+        right->SetCallback(button_right_callback);
+        modifier->SetCallback(button_modifier_callback);
+    }
+
+    bool IsAngleGreater(float old_angle, float new_angle) const {
+        constexpr float TAU = Common::PI * 2.0f;
+        // Use wider angle to ease the transition.
+        constexpr float aperture = TAU * 0.15f;
+        const float top_limit = new_angle + aperture;
+        return (old_angle > new_angle && old_angle <= top_limit) ||
+               (old_angle + TAU > new_angle && old_angle + TAU <= top_limit);
+    }
+
+    bool IsAngleSmaller(float old_angle, float new_angle) const {
+        constexpr float TAU = Common::PI * 2.0f;
+        // Use wider angle to ease the transition.
+        constexpr float aperture = TAU * 0.15f;
+        const float bottom_limit = new_angle - aperture;
+        return (old_angle >= bottom_limit && old_angle < new_angle) ||
+               (old_angle - TAU >= bottom_limit && old_angle - TAU < new_angle);
+    }
+
+    float GetAngle(std::chrono::time_point<std::chrono::steady_clock> now) const {
+        constexpr float TAU = Common::PI * 2.0f;
+        float new_angle = angle;
+
+        auto time_difference = static_cast<float>(
+            std::chrono::duration_cast<std::chrono::microseconds>(now - last_update).count());
+        time_difference /= 1000.0f * 1000.0f;
+        if (time_difference > 0.5f) {
+            time_difference = 0.5f;
+        }
+
+        if (IsAngleGreater(new_angle, goal_angle)) {
+            new_angle -= modifier_angle * time_difference;
+            if (new_angle < 0) {
+                new_angle += TAU;
+            }
+            if (!IsAngleGreater(new_angle, goal_angle)) {
+                return goal_angle;
+            }
+        } else if (IsAngleSmaller(new_angle, goal_angle)) {
+            new_angle += modifier_angle * time_difference;
+            if (new_angle >= TAU) {
+                new_angle -= TAU;
+            }
+            if (!IsAngleSmaller(new_angle, goal_angle)) {
+                return goal_angle;
+            }
+        } else {
+            return goal_angle;
+        }
+        return new_angle;
+    }
+
+    void SetGoalAngle(bool r, bool l, bool u, bool d) {
+        // Move to the right
+        if (r && !u && !d) {
+            goal_angle = 0.0f;
+        }
+
+        // Move to the upper right
+        if (r && u && !d) {
+            goal_angle = Common::PI * 0.25f;
+        }
+
+        // Move up
+        if (u && !l && !r) {
+            goal_angle = Common::PI * 0.5f;
+        }
+
+        // Move to the upper left
+        if (l && u && !d) {
+            goal_angle = Common::PI * 0.75f;
+        }
+
+        // Move to the left
+        if (l && !u && !d) {
+            goal_angle = Common::PI;
+        }
+
+        // Move to the bottom left
+        if (l && !u && d) {
+            goal_angle = Common::PI * 1.25f;
+        }
+
+        // Move down
+        if (d && !l && !r) {
+            goal_angle = Common::PI * 1.5f;
+        }
+
+        // Move to the bottom right
+        if (r && !u && d) {
+            goal_angle = Common::PI * 1.75f;
+        }
+    }
+
+    void UpdateUpButtonStatus(Input::CallbackStatus button_callback) {
+        up_status = button_callback.button_status.value;
+        UpdateStatus();
+    }
+
+    void UpdateDownButtonStatus(Input::CallbackStatus button_callback) {
+        down_status = button_callback.button_status.value;
+        UpdateStatus();
+    }
+
+    void UpdateLeftButtonStatus(Input::CallbackStatus button_callback) {
+        left_status = button_callback.button_status.value;
+        UpdateStatus();
+    }
+
+    void UpdateRightButtonStatus(Input::CallbackStatus button_callback) {
+        right_status = button_callback.button_status.value;
+        UpdateStatus();
+    }
+
+    void UpdateModButtonStatus(Input::CallbackStatus button_callback) {
+        modifier_status = button_callback.button_status.value;
+        UpdateStatus();
+    }
+
+    void UpdateStatus() {
+        const float coef = modifier_status ? modifier_scale : 1.0f;
+
+        bool r = right_status;
+        bool l = left_status;
+        bool u = up_status;
+        bool d = down_status;
+
+        // Eliminate contradictory movements
+        if (r && l) {
+            r = false;
+            l = false;
+        }
+        if (u && d) {
+            u = false;
+            d = false;
+        }
+
+        // Move if a key is pressed
+        if (r || l || u || d) {
+            amplitude = coef;
+        } else {
+            amplitude = 0;
+        }
+
+        const auto now = std::chrono::steady_clock::now();
+        const auto time_difference = static_cast<u64>(
+            std::chrono::duration_cast<std::chrono::milliseconds>(now - last_update).count());
+
+        if (time_difference < 10) {
+            // Disable analog mode if inputs are too fast
+            SetGoalAngle(r, l, u, d);
+            angle = goal_angle;
+        } else {
+            angle = GetAngle(now);
+            SetGoalAngle(r, l, u, d);
+        }
+
+        last_update = now;
+        Input::CallbackStatus status{
+            .type = Input::InputType::Stick,
+            .stick_status = GetStatus(),
+        };
+        TriggerOnChange(status);
+    }
+
+    Input::StickStatus GetStatus() const {
+        Input::StickStatus status{};
+        status.x.properties = properties;
+        status.y.properties = properties;
+        if (Settings::values.emulate_analog_keyboard) {
+            const auto now = std::chrono::steady_clock::now();
+            float angle_ = GetAngle(now);
+            status.x.raw_value = std::cos(angle_) * amplitude;
+            status.y.raw_value = std::sin(angle_) * amplitude;
+            return status;
+        }
+        constexpr float SQRT_HALF = 0.707106781f;
+        int x = 0, y = 0;
+        if (right_status) {
+            ++x;
+        }
+        if (left_status) {
+            --x;
+        }
+        if (up_status) {
+            ++y;
+        }
+        if (down_status) {
+            --y;
+        }
+        const float coef = modifier_status ? modifier_scale : 1.0f;
+        status.x.raw_value = static_cast<float>(x) * coef * (y == 0 ? 1.0f : SQRT_HALF);
+        status.y.raw_value = static_cast<float>(y) * coef * (x == 0 ? 1.0f : SQRT_HALF);
+        return status;
+    }
+
+private:
+    Button up;
+    Button down;
+    Button left;
+    Button right;
+    Button modifier;
+    float modifier_scale;
+    float modifier_angle;
+    float angle{};
+    float goal_angle{};
+    float amplitude{};
+    bool up_status;
+    bool down_status;
+    bool left_status;
+    bool right_status;
+    bool modifier_status;
+    const Input::AnalogProperties properties{0.0f, 1.0f, 0.5f, 0.0f, false};
+    std::chrono::time_point<std::chrono::steady_clock> last_update;
+};
+
+std::unique_ptr<Input::InputDevice> StickFromButton::Create(const Common::ParamPackage& params) {
+    const std::string null_engine = Common::ParamPackage{{"engine", "null"}}.Serialize();
+    auto up = Input::CreateDeviceFromString<Input::InputDevice>(params.Get("up", null_engine));
+    auto down = Input::CreateDeviceFromString<Input::InputDevice>(params.Get("down", null_engine));
+    auto left = Input::CreateDeviceFromString<Input::InputDevice>(params.Get("left", null_engine));
+    auto right =
+        Input::CreateDeviceFromString<Input::InputDevice>(params.Get("right", null_engine));
+    auto modifier =
+        Input::CreateDeviceFromString<Input::InputDevice>(params.Get("modifier", null_engine));
+    auto modifier_scale = params.Get("modifier_scale", 0.5f);
+    auto modifier_angle = params.Get("modifier_angle", 5.5f);
+    return std::make_unique<Stick>(std::move(up), std::move(down), std::move(left),
+                                   std::move(right), std::move(modifier), modifier_scale,
+                                   modifier_angle);
+}
+
+} // namespace InputCommon