input_common: touch: Rewrite touch driver to support multiple touch points

src/input_common/drivers/touch_screen.cpp

@@ -14,38 +14,93 @@ constexpr PadIdentifier identifier = {
 
 TouchScreen::TouchScreen(std::string input_engine_) : InputEngine(std::move(input_engine_)) {
     PreSetController(identifier);
+    ReleaseAllTouch();
 }
 
-void TouchScreen::TouchMoved(float x, float y, std::size_t finger) {
-    if (finger >= 16) {
+void TouchScreen::TouchMoved(float x, float y, std::size_t finger_id) {
+    const auto index = GetIndexFromFingerId(finger_id);
+    if (!index) {
+        // Touch doesn't exist handle it as a new one
+        TouchPressed(x, y, finger_id);
         return;
     }
-    TouchPressed(x, y, finger);
+    const auto i = index.value();
+    fingers[i].is_active = true;
+    SetButton(identifier, static_cast<int>(i), true);
+    SetAxis(identifier, static_cast<int>(i * 2), x);
+    SetAxis(identifier, static_cast<int>(i * 2 + 1), y);
 }
 
-void TouchScreen::TouchPressed(float x, float y, std::size_t finger) {
-    if (finger >= 16) {
+void TouchScreen::TouchPressed(float x, float y, std::size_t finger_id) {
+    if (GetIndexFromFingerId(finger_id)) {
+        // Touch already exist. Just update the data
+        TouchMoved(x, y, finger_id);
         return;
     }
-    SetButton(identifier, static_cast<int>(finger), true);
-    SetAxis(identifier, static_cast<int>(finger * 2), x);
-    SetAxis(identifier, static_cast<int>(finger * 2 + 1), y);
+    const auto index = GetNextFreeIndex();
+    if (!index) {
+        // No free entries. Ignore input
+        return;
+    }
+    const auto i = index.value();
+    fingers[i].is_enabled = true;
+    fingers[i].finger_id = finger_id;
+    TouchMoved(x, y, finger_id);
 }
 
-void TouchScreen::TouchReleased(std::size_t finger) {
-    if (finger >= 16) {
+void TouchScreen::TouchReleased(std::size_t finger_id) {
+    const auto index = GetIndexFromFingerId(finger_id);
+    if (!index) {
         return;
     }
-    SetButton(identifier, static_cast<int>(finger), false);
-    SetAxis(identifier, static_cast<int>(finger * 2), 0.0f);
-    SetAxis(identifier, static_cast<int>(finger * 2 + 1), 0.0f);
+    const auto i = index.value();
+    fingers[i].is_enabled = false;
+    SetButton(identifier, static_cast<int>(i), false);
+    SetAxis(identifier, static_cast<int>(i * 2), 0.0f);
+    SetAxis(identifier, static_cast<int>(i * 2 + 1), 0.0f);
+}
+
+std::optional<std::size_t> TouchScreen::GetIndexFromFingerId(std::size_t finger_id) const {
+    for (std::size_t index = 0; index < MAX_FINGER_COUNT; ++index) {
+        const auto& finger = fingers[index];
+        if (!finger.is_enabled) {
+            continue;
+        }
+        if (finger.finger_id == finger_id) {
+            return index;
+        }
+    }
+    return std::nullopt;
+}
+
+std::optional<std::size_t> TouchScreen::GetNextFreeIndex() const {
+    for (std::size_t index = 0; index < MAX_FINGER_COUNT; ++index) {
+        if (!fingers[index].is_enabled) {
+            return index;
+        }
+    }
+    return std::nullopt;
+}
+
+void TouchScreen::ClearActiveFlag() {
+    for (auto& finger : fingers) {
+        finger.is_active = false;
+    }
+}
+
+void TouchScreen::ReleaseInactiveTouch() {
+    for (const auto& finger : fingers) {
+        if (!finger.is_active) {
+            TouchReleased(finger.finger_id);
+        }
+    }
 }
 
 void TouchScreen::ReleaseAllTouch() {
-    for (int index = 0; index < 16; ++index) {
-        SetButton(identifier, index, false);
-        SetAxis(identifier, index * 2, 0.0f);
-        SetAxis(identifier, index * 2 + 1, 0.0f);
+    for (const auto& finger : fingers) {
+        if (finger.is_enabled) {
+            TouchReleased(finger.finger_id);
+        }
     }
 }
 

src/input_common/drivers/touch_screen.h

@@ -3,41 +3,65 @@
 
 #pragma once
 
+#include <optional>
+
 #include "input_common/input_engine.h"
 
 namespace InputCommon {
 
 /**
- * A button device factory representing a keyboard. It receives keyboard events and forward them
- * to all button devices it created.
+ * A touch device factory representing a touch screen. It receives touch events and forward them
+ * to all touch devices it created.
  */
 class TouchScreen final : public InputEngine {
 public:
     explicit TouchScreen(std::string input_engine_);
 
     /**
-     * Signals that mouse has moved.
-     * @param x the x-coordinate of the cursor
-     * @param y the y-coordinate of the cursor
-     * @param center_x the x-coordinate of the middle of the screen
-     * @param center_y the y-coordinate of the middle of the screen
+     * Signals that touch has moved and marks this touch point as active
+     * @param x new horizontal position
+     * @param y new vertical position
+     * @param finger_id of the touch point to be updated
      */
-    void TouchMoved(float x, float y, std::size_t finger);
+    void TouchMoved(float x, float y, std::size_t finger_id);
 
     /**
-     * Sets the status of all buttons bound with the key to pressed
-     * @param key_code the code of the key to press
+     * Signals and creates a new touch point with this finger id
+     * @param x starting horizontal position
+     * @param y starting vertical position
+     * @param finger_id to be assigned to the new touch point
      */
-    void TouchPressed(float x, float y, std::size_t finger);
+    void TouchPressed(float x, float y, std::size_t finger_id);
 
     /**
-     * Sets the status of all buttons bound with the key to released
-     * @param key_code the code of the key to release
+     * Signals and resets the touch point related to the this finger id
+     * @param finger_id to be released
      */
-    void TouchReleased(std::size_t finger);
+    void TouchReleased(std::size_t finger_id);
+
+    /// Resets the active flag for each touch point
+    void ClearActiveFlag();
+
+    /// Releases all touch that haven't been marked as active
+    void ReleaseInactiveTouch();
 
     /// Resets all inputs to their initial value
     void ReleaseAllTouch();
+
+private:
+    static constexpr std::size_t MAX_FINGER_COUNT = 16;
+
+    struct TouchStatus {
+        std::size_t finger_id{};
+        bool is_enabled{};
+        bool is_active{};
+    };
+
+    std::optional<std::size_t> GetIndexFromFingerId(std::size_t finger_id) const;
+
+    std::optional<std::size_t> GetNextFreeIndex() const;
+
+    std::array<TouchStatus, MAX_FINGER_COUNT> fingers{};
 };
 
 } // namespace InputCommon