4 files changed, 279 insertions, 0 deletions

diff --git a/src/common/quaternion.h b/src/common/quaternion.h
index da44f35cd..4d0871eb4 100644
--- a/src/common/quaternion.h
+++ b/src/common/quaternion.h
@@ -36,6 +36,36 @@ public:
         T length = std::sqrt(xyz.Length2() + w * w);
         return {xyz / length, w / length};
     }
+
+    [[nodiscard]] std::array<decltype(-T{}), 16> ToMatrix() const {
+        const T x2 = xyz[0] * xyz[0];
+        const T y2 = xyz[1] * xyz[1];
+        const T z2 = xyz[2] * xyz[2];
+
+        const T xy = xyz[0] * xyz[1];
+        const T wz = w * xyz[2];
+        const T xz = xyz[0] * xyz[2];
+        const T wy = w * xyz[1];
+        const T yz = xyz[1] * xyz[2];
+        const T wx = w * xyz[0];
+
+        return {1.0f - 2.0f * (y2 + z2),
+                2.0f * (xy + wz),
+                2.0f * (xz - wy),
+                0.0f,
+                2.0f * (xy - wz),
+                1.0f - 2.0f * (x2 + z2),
+                2.0f * (yz + wx),
+                0.0f,
+                2.0f * (xz + wy),
+                2.0f * (yz - wx),
+                1.0f - 2.0f * (x2 + y2),
+                0.0f,
+                0.0f,
+                0.0f,
+                0.0f,
+                1.0f};
+    }
 };
 
 template <typename T>
diff --git a/src/input_common/CMakeLists.txt b/src/input_common/CMakeLists.txt
index 56267c8a8..c673b8389 100644
--- a/src/input_common/CMakeLists.txt
+++ b/src/input_common/CMakeLists.txt
@@ -7,6 +7,8 @@ add_library(input_common STATIC
     main.h
     motion_emu.cpp
     motion_emu.h
+    motion_input.cpp
+    motion_input.h
     settings.cpp
     settings.h
     gcadapter/gc_adapter.cpp
diff --git a/src/input_common/motion_input.cpp b/src/input_common/motion_input.cpp
new file mode 100644
index 000000000..e3aec04e1
--- /dev/null
+++ b/src/input_common/motion_input.cpp
@@ -0,0 +1,185 @@
+#include "input_common/motion_input.h"
+
+namespace InputCommon {
+
+MotionInput::MotionInput(f32 new_kp, f32 new_ki, f32 new_kd) : kp(new_kp), ki(new_ki), kd(new_kd) {
+    accel = {};
+    gyro = {};
+    gyro_drift = {};
+    gyro_threshold = 0;
+    rotations = {};
+
+    quat.w = 0;
+    quat.xyz[0] = 0;
+    quat.xyz[1] = 0;
+    quat.xyz[2] = -1;
+
+    real_error = {};
+    integral_error = {};
+    derivative_error = {};
+
+    reset_counter = 0;
+    reset_enabled = true;
+}
+
+void MotionInput::SetAcceleration(Common::Vec3f acceleration) {
+    accel = acceleration;
+}
+
+void MotionInput::SetGyroscope(Common::Vec3f gyroscope) {
+    gyro = gyroscope - gyro_drift;
+    if (gyro.Length2() < gyro_threshold) {
+        gyro = {};
+    }
+}
+
+void MotionInput::SetQuaternion(Common::Quaternion<f32> quaternion) {
+    quat = quaternion;
+}
+
+void MotionInput::SetGyroDrift(Common::Vec3f drift) {
+    drift = gyro_drift;
+}
+
+void MotionInput::SetGyroThreshold(f32 threshold) {
+    gyro_threshold = threshold;
+}
+
+void MotionInput::EnableReset(bool reset) {
+    reset_enabled = reset;
+}
+
+void MotionInput::ResetRotations() {
+    rotations = {};
+}
+
+bool MotionInput::IsMoving(f32 sensitivity) {
+    return gyro.Length2() >= sensitivity || accel.Length() <= 0.9f || accel.Length() >= 1.1f;
+}
+
+bool MotionInput::IsCalibrated(f32 sensitivity) {
+    return real_error.Length() > sensitivity;
+}
+
+void MotionInput::UpdateRotation(u64 elapsed_time) {
+    rotations += gyro * elapsed_time;
+}
+
+void MotionInput::UpdateOrientation(u64 elapsed_time) {
+    // Short name local variable for readability
+    f32 q1 = quat.w, q2 = quat.xyz[0], q3 = quat.xyz[1], q4 = quat.xyz[2];
+    f32 sample_period = elapsed_time / 1000000.0f;
+
+    auto normal_accel = accel.Normalized();
+    auto rad_gyro = gyro * 3.1415926535f;
+    rad_gyro.z = -rad_gyro.z;
+
+    // Ignore drift correction if acceleration is not present
+    if (normal_accel.Length() == 1.0f) {
+        f32 ax = -normal_accel.x;
+        f32 ay = normal_accel.y;
+        f32 az = -normal_accel.z;
+        f32 vx, vy, vz;
+        Common::Vec3f new_real_error;
+
+        // Estimated direction of gravity
+        vx = 2.0f * (q2 * q4 - q1 * q3);
+        vy = 2.0f * (q1 * q2 + q3 * q4);
+        vz = q1 * q1 - q2 * q2 - q3 * q3 + q4 * q4;
+
+        // Error is cross product between estimated direction and measured direction of gravity
+        new_real_error.x = ay * vz - az * vy;
+        new_real_error.y = az * vx - ax * vz;
+        new_real_error.x = ax * vy - ay * vx;
+
+        derivative_error = new_real_error - real_error;
+        real_error = new_real_error;
+
+        // Prevent integral windup
+        if (ki != 0.0f) {
+            integral_error += real_error;
+        } else {
+            integral_error = {};
+        }
+
+        // Apply feedback terms
+        rad_gyro += kp * real_error;
+        rad_gyro += ki * integral_error;
+        rad_gyro += kd * derivative_error;
+    }
+
+    f32 gx = rad_gyro.y;
+    f32 gy = rad_gyro.x;
+    f32 gz = rad_gyro.z;
+
+    // Integrate rate of change of quaternion
+    f32 pa, pb, pc;
+    pa = q2;
+    pb = q3;
+    pc = q4;
+    q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * sample_period);
+    q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * sample_period);
+    q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * sample_period);
+    q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * sample_period);
+
+    quat.w = q1;
+    quat.xyz[0] = q2;
+    quat.xyz[1] = q3;
+    quat.xyz[2] = q4;
+    quat = quat.Normalized();
+}
+
+std::array<Common::Vec3f, 3> MotionInput::GetOrientation() {
+    std::array<Common::Vec3f, 3> orientation = {};
+    Common::Quaternion<float> quad;
+
+    quad.w = -quat.xyz[2];
+    quad.xyz[0] = -quat.xyz[1];
+    quad.xyz[1] = -quat.xyz[0];
+    quad.xyz[2] = -quat.w;
+
+    std::array<float, 16> matrix4x4 = quad.ToMatrix();
+
+    orientation[0] = Common::Vec3f(matrix4x4[0], matrix4x4[1], matrix4x4[2]);
+    orientation[1] = Common::Vec3f(matrix4x4[4], matrix4x4[5], matrix4x4[6]);
+    orientation[2] = Common::Vec3f(matrix4x4[8], matrix4x4[9], matrix4x4[10]);
+
+    return orientation;
+}
+
+Common::Vec3f MotionInput::GetAcceleration() {
+    return accel;
+}
+
+Common::Vec3f MotionInput::GetGyroscope() {
+    return gyro;
+}
+
+Common::Quaternion<f32> MotionInput::GetQuaternion() {
+    return quat;
+}
+
+Common::Vec3f MotionInput::GetRotations() {
+    return rotations;
+}
+
+void MotionInput::resetOrientation() {
+    if (!reset_enabled) {
+        return;
+    }
+    if (!IsMoving(0.5f) && accel.z <= -0.9f) {
+        ++reset_counter;
+        if (reset_counter > 900) {
+            // TODO: calculate quaternion from gravity vector
+            quat.w = 0;
+            quat.xyz[0] = 0;
+            quat.xyz[1] = 0;
+            quat.xyz[2] = -1;
+            integral_error = {};
+            reset_counter = 0;
+        }
+    } else {
+        reset_counter = 0;
+    }
+}
+} // namespace InputCommon
\ No newline at end of file
diff --git a/src/input_common/motion_input.h b/src/input_common/motion_input.h
new file mode 100644
index 000000000..4b8093d8c
--- /dev/null
+++ b/src/input_common/motion_input.h
@@ -0,0 +1,62 @@
+// Copyright 2014 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_types.h"
+#include "common/quaternion.h"
+#include "common/vector_math.h"
+
+namespace InputCommon {
+
+class MotionInput {
+public:
+    MotionInput(f32 new_kp, f32 new_ki, f32 new_kd);
+
+    void SetAcceleration(Common::Vec3f acceleration);
+    void SetGyroscope(Common::Vec3f acceleration);
+    void SetQuaternion(Common::Quaternion<f32> quaternion);
+    void SetGyroDrift(Common::Vec3f drift);
+    void SetGyroThreshold(f32 threshold);
+
+    void EnableReset(bool reset);
+    void ResetRotations();
+
+    void UpdateRotation(u64 elapsed_time);
+    void UpdateOrientation(u64 elapsed_time);
+
+    std::array<Common::Vec3f, 3> GetOrientation();
+    Common::Vec3f GetAcceleration();
+    Common::Vec3f GetGyroscope();
+    Common::Vec3f GetRotations();
+    Common::Quaternion<f32> GetQuaternion();
+
+    bool IsMoving(f32 sensitivity);
+    bool IsCalibrated(f32 sensitivity);
+
+    // PID constants
+    const f32 kp;
+    const f32 ki;
+    const f32 kd;
+
+private:
+    void resetOrientation();
+
+    // PID errors
+    Common::Vec3f real_error;
+    Common::Vec3f integral_error;
+    Common::Vec3f derivative_error;
+
+    Common::Quaternion<f32> quat;
+    Common::Vec3f rotations;
+    Common::Vec3f accel;
+    Common::Vec3f gyro;
+    Common::Vec3f gyro_drift;
+
+    f32 gyro_threshold;
+    f32 reset_counter;
+    bool reset_enabled;
+};
+
+} // namespace InputCommon