From a220d8799ed332c1d8f2231b18079b1210511bcd Mon Sep 17 00:00:00 2001 From: german Date: Sat, 3 Oct 2020 22:22:01 -0500 Subject: [PATCH] Add compatibility with only accelerometer and auto calibrate for drift --- src/input_common/motion_input.cpp | 112 +++++++++++++++++++++++++++--- src/input_common/motion_input.h | 6 +- 2 files changed, 106 insertions(+), 12 deletions(-) diff --git a/src/input_common/motion_input.cpp b/src/input_common/motion_input.cpp index 22a849866d..d3e7360448 100644 --- a/src/input_common/motion_input.cpp +++ b/src/input_common/motion_input.cpp @@ -16,8 +16,16 @@ void MotionInput::SetAcceleration(const Common::Vec3f& acceleration) { void MotionInput::SetGyroscope(const Common::Vec3f& gyroscope) { gyro = gyroscope - gyro_drift; + + // Auto adjust drift to minimize drift + if (!IsMoving(0.1f)) { + gyro_drift = (gyro_drift * 0.9999f) + (gyroscope * 0.0001f); + } + if (gyro.Length2() < gyro_threshold) { gyro = {}; + } else { + only_accelerometer = false; } } @@ -49,7 +57,7 @@ bool MotionInput::IsCalibrated(f32 sensitivity) const { return real_error.Length() < sensitivity; } -void MotionInput::UpdateRotation(u64 elapsed_time) { +void MotionInput::UpdateRotation(const u64 elapsed_time) { const f32 sample_period = elapsed_time / 1000000.0f; if (sample_period > 0.1f) { return; @@ -57,7 +65,7 @@ void MotionInput::UpdateRotation(u64 elapsed_time) { rotations += gyro * sample_period; } -void MotionInput::UpdateOrientation(u64 elapsed_time) { +void MotionInput::UpdateOrientation(const u64 elapsed_time) { if (!IsCalibrated(0.1f)) { ResetOrientation(); } @@ -68,7 +76,7 @@ void MotionInput::UpdateOrientation(u64 elapsed_time) { f32 q4 = quat.xyz[2]; const f32 sample_period = elapsed_time / 1000000.0f; - // ignore invalid elapsed time + // Ignore invalid elapsed time if (sample_period > 0.1f) { return; } @@ -80,6 +88,13 @@ void MotionInput::UpdateOrientation(u64 elapsed_time) { rad_gyro.y = -swap; rad_gyro.z = -rad_gyro.z; + // Clear gyro values if there is no gyro present + if (only_accelerometer) { + rad_gyro.x = 0; + rad_gyro.y = 0; + rad_gyro.z = 0; + } + // Ignore drift correction if acceleration is not reliable if (accel.Length() >= 0.75f && accel.Length() <= 1.25f) { const f32 ax = -normal_accel.x; @@ -92,8 +107,11 @@ void MotionInput::UpdateOrientation(u64 elapsed_time) { const f32 vz = q1 * q1 - q2 * q2 - q3 * q3 + q4 * q4; // Error is cross product between estimated direction and measured direction of gravity - const Common::Vec3f new_real_error = {az * vx - ax * vz, ay * vz - az * vy, - ax * vy - ay * vx}; + const Common::Vec3f new_real_error = { + az * vx - ax * vz, + ay * vz - az * vy, + ax * vy - ay * vx, + }; derivative_error = new_real_error - real_error; real_error = new_real_error; @@ -106,9 +124,22 @@ void MotionInput::UpdateOrientation(u64 elapsed_time) { } // Apply feedback terms - rad_gyro += kp * real_error; - rad_gyro += ki * integral_error; - rad_gyro += kd * derivative_error; + if (!only_accelerometer) { + rad_gyro += kp * real_error; + rad_gyro += ki * integral_error; + rad_gyro += kd * derivative_error; + } else { + // Give more weight to acelerometer values to compensate for the lack of gyro + rad_gyro += 35.0f * kp * real_error; + rad_gyro += 10.0f * ki * integral_error; + rad_gyro += 10.0f * kd * derivative_error; + + // Emulate gyro values for games that need them + gyro.x = -rad_gyro.y; + gyro.y = rad_gyro.x; + gyro.z = -rad_gyro.z; + UpdateRotation(elapsed_time); + } } const f32 gx = rad_gyro.y; @@ -143,6 +174,67 @@ std::array MotionInput::GetOrientation() const { Common::Vec3f(-matrix4x4[8], -matrix4x4[9], matrix4x4[10])}; } +void MotionInput::SetOrientationFromAccelerometer() { + int iterations = 0; + const f32 sample_period = 0.015f; + + const auto normal_accel = accel.Normalized(); + const f32 ax = -normal_accel.x; + const f32 ay = normal_accel.y; + const f32 az = -normal_accel.z; + + while (!IsCalibrated(0.01f) && ++iterations < 100) { + // Short name local variable for readability + f32 q1 = quat.w; + f32 q2 = quat.xyz[0]; + f32 q3 = quat.xyz[1]; + f32 q4 = quat.xyz[2]; + + Common::Vec3f rad_gyro = {}; + const f32 ax = -normal_accel.x; + const f32 ay = normal_accel.y; + const f32 az = -normal_accel.z; + + // Estimated direction of gravity + const f32 vx = 2.0f * (q2 * q4 - q1 * q3); + const f32 vy = 2.0f * (q1 * q2 + q3 * q4); + const f32 vz = q1 * q1 - q2 * q2 - q3 * q3 + q4 * q4; + + // Error is cross product between estimated direction and measured direction of gravity + const Common::Vec3f new_real_error = { + az * vx - ax * vz, + ay * vz - az * vy, + ax * vy - ay * vx, + }; + + derivative_error = new_real_error - real_error; + real_error = new_real_error; + + rad_gyro += 10.0f * kp * real_error; + rad_gyro += 5.0f * ki * integral_error; + rad_gyro += 10.0f * kd * derivative_error; + + const f32 gx = rad_gyro.y; + const f32 gy = rad_gyro.x; + const f32 gz = rad_gyro.z; + + // Integrate rate of change of quaternion + const f32 pa = q2; + const f32 pb = q3; + const f32 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(); + } +} + Common::Vec3f MotionInput::GetAcceleration() const { return accel; } @@ -160,17 +252,17 @@ Common::Vec3f MotionInput::GetRotations() const { } void MotionInput::ResetOrientation() { - if (!reset_enabled) { + if (!reset_enabled || only_accelerometer) { 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; + SetOrientationFromAccelerometer(); integral_error = {}; reset_counter = 0; } diff --git a/src/input_common/motion_input.h b/src/input_common/motion_input.h index 54b4439d9d..f6c1fece7e 100644 --- a/src/input_common/motion_input.h +++ b/src/input_common/motion_input.h @@ -29,8 +29,8 @@ public: void EnableReset(bool reset); void ResetRotations(); - void UpdateRotation(u64 elapsed_time); - void UpdateOrientation(u64 elapsed_time); + void UpdateRotation(const u64 elapsed_time); + void UpdateOrientation(const u64 elapsed_time); std::array GetOrientation() const; Common::Vec3f GetAcceleration() const; @@ -43,6 +43,7 @@ public: private: void ResetOrientation(); + void SetOrientationFromAccelerometer(); // PID constants const f32 kp; @@ -63,6 +64,7 @@ private: f32 gyro_threshold = 0.0f; u32 reset_counter = 0; bool reset_enabled = true; + bool only_accelerometer = true; }; } // namespace InputCommon