godot/modules/mobile_vr/mobile_vr_interface.cpp
Rémi Verschelde a7f49ac9a1 Update copyright statements to 2020
Happy new year to the wonderful Godot community!

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2020-01-01 11:16:22 +01:00

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/*************************************************************************/
/* mobile_vr_interface.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
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/* the following conditions: */
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/* The above copyright notice and this permission notice shall be */
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/*************************************************************************/
#include "mobile_vr_interface.h"
#include "core/os/input.h"
#include "core/os/os.h"
#include "servers/visual/visual_server_globals.h"
StringName MobileVRInterface::get_name() const {
return "Native mobile";
};
int MobileVRInterface::get_capabilities() const {
return ARVRInterface::ARVR_STEREO;
};
Vector3 MobileVRInterface::scale_magneto(const Vector3 &p_magnetometer) {
// Our magnetometer doesn't give us nice clean data.
// Well it may on Mac OS X because we're getting a calibrated value in the current implementation but Android we're getting raw data.
// This is a fairly simple adjustment we can do to correct for the magnetometer data being elliptical
Vector3 mag_raw = p_magnetometer;
Vector3 mag_scaled = p_magnetometer;
// update our variables every x frames
if (mag_count > 20) {
mag_current_min = mag_next_min;
mag_current_max = mag_next_max;
mag_count = 0;
} else {
mag_count++;
};
// adjust our min and max
if (mag_raw.x > mag_next_max.x) mag_next_max.x = mag_raw.x;
if (mag_raw.y > mag_next_max.y) mag_next_max.y = mag_raw.y;
if (mag_raw.z > mag_next_max.z) mag_next_max.z = mag_raw.z;
if (mag_raw.x < mag_next_min.x) mag_next_min.x = mag_raw.x;
if (mag_raw.y < mag_next_min.y) mag_next_min.y = mag_raw.y;
if (mag_raw.z < mag_next_min.z) mag_next_min.z = mag_raw.z;
// scale our x, y and z
if (!(mag_current_max.x - mag_current_min.x)) {
mag_raw.x -= (mag_current_min.x + mag_current_max.x) / 2.0;
mag_scaled.x = (mag_raw.x - mag_current_min.x) / ((mag_current_max.x - mag_current_min.x) * 2.0 - 1.0);
};
if (!(mag_current_max.y - mag_current_min.y)) {
mag_raw.y -= (mag_current_min.y + mag_current_max.y) / 2.0;
mag_scaled.y = (mag_raw.y - mag_current_min.y) / ((mag_current_max.y - mag_current_min.y) * 2.0 - 1.0);
};
if (!(mag_current_max.z - mag_current_min.z)) {
mag_raw.z -= (mag_current_min.z + mag_current_max.z) / 2.0;
mag_scaled.z = (mag_raw.z - mag_current_min.z) / ((mag_current_max.z - mag_current_min.z) * 2.0 - 1.0);
};
return mag_scaled;
};
Basis MobileVRInterface::combine_acc_mag(const Vector3 &p_grav, const Vector3 &p_magneto) {
// yup, stock standard cross product solution...
Vector3 up = -p_grav.normalized();
Vector3 magneto_east = up.cross(p_magneto.normalized()); // or is this west?, but should be horizon aligned now
magneto_east.normalize();
Vector3 magneto = up.cross(magneto_east); // and now we have a horizon aligned north
magneto.normalize();
// We use our gravity and magnetometer vectors to construct our matrix
Basis acc_mag_m3;
acc_mag_m3.elements[0] = -magneto_east;
acc_mag_m3.elements[1] = up;
acc_mag_m3.elements[2] = magneto;
return acc_mag_m3;
};
void MobileVRInterface::set_position_from_sensors() {
_THREAD_SAFE_METHOD_
// this is a helper function that attempts to adjust our transform using our 9dof sensors
// 9dof is a misleading marketing term coming from 3 accelerometer axis + 3 gyro axis + 3 magnetometer axis = 9 axis
// but in reality this only offers 3 dof (yaw, pitch, roll) orientation
uint64_t ticks = OS::get_singleton()->get_ticks_usec();
uint64_t ticks_elapsed = ticks - last_ticks;
float delta_time = (double)ticks_elapsed / 1000000.0;
// few things we need
Input *input = Input::get_singleton();
Vector3 down(0.0, -1.0, 0.0); // Down is Y negative
Vector3 north(0.0, 0.0, 1.0); // North is Z positive
// make copies of our inputs
bool has_grav = false;
Vector3 acc = input->get_accelerometer();
Vector3 gyro = input->get_gyroscope();
Vector3 grav = input->get_gravity();
Vector3 magneto = scale_magneto(input->get_magnetometer()); // this may be overkill on iOS because we're already getting a calibrated magnetometer reading
if (sensor_first) {
sensor_first = false;
} else {
acc = scrub(acc, last_accerometer_data, 2, 0.2);
magneto = scrub(magneto, last_magnetometer_data, 3, 0.3);
};
last_accerometer_data = acc;
last_magnetometer_data = magneto;
if (grav.length() < 0.1) {
// not ideal but use our accelerometer, this will contain shakey shakey user behaviour
// maybe look into some math but I'm guessing that if this isn't available, its because we lack the gyro sensor to actually work out
// what a stable gravity vector is
grav = acc;
if (grav.length() > 0.1) {
has_grav = true;
};
} else {
has_grav = true;
};
bool has_magneto = magneto.length() > 0.1;
if (gyro.length() > 0.1) {
/* this can return to 0.0 if the user doesn't move the phone, so once on, it's on */
has_gyro = true;
};
if (has_gyro) {
// start with applying our gyro (do NOT smooth our gyro!)
Basis rotate;
rotate.rotate(orientation.get_axis(0), gyro.x * delta_time);
rotate.rotate(orientation.get_axis(1), gyro.y * delta_time);
rotate.rotate(orientation.get_axis(2), gyro.z * delta_time);
orientation = rotate * orientation;
tracking_state = ARVRInterface::ARVR_NORMAL_TRACKING;
};
///@TODO improve this, the magnetometer is very fidgity sometimes flipping the axis for no apparent reason (probably a bug on my part)
// if you have a gyro + accelerometer that combo tends to be better then combining all three but without a gyro you need the magnetometer..
if (has_magneto && has_grav && !has_gyro) {
// convert to quaternions, easier to smooth those out
Quat transform_quat(orientation);
Quat acc_mag_quat(combine_acc_mag(grav, magneto));
transform_quat = transform_quat.slerp(acc_mag_quat, 0.1);
orientation = Basis(transform_quat);
tracking_state = ARVRInterface::ARVR_NORMAL_TRACKING;
} else if (has_grav) {
// use gravity vector to make sure down is down...
// transform gravity into our world space
grav.normalize();
Vector3 grav_adj = orientation.xform(grav);
float dot = grav_adj.dot(down);
if ((dot > -1.0) && (dot < 1.0)) {
// axis around which we have this rotation
Vector3 axis = grav_adj.cross(down);
axis.normalize();
Basis drift_compensation(axis, acos(dot) * delta_time * 10);
orientation = drift_compensation * orientation;
};
};
// JIC
orientation.orthonormalize();
last_ticks = ticks;
};
void MobileVRInterface::_bind_methods() {
ClassDB::bind_method(D_METHOD("set_eye_height", "eye_height"), &MobileVRInterface::set_eye_height);
ClassDB::bind_method(D_METHOD("get_eye_height"), &MobileVRInterface::get_eye_height);
ClassDB::bind_method(D_METHOD("set_iod", "iod"), &MobileVRInterface::set_iod);
ClassDB::bind_method(D_METHOD("get_iod"), &MobileVRInterface::get_iod);
ClassDB::bind_method(D_METHOD("set_display_width", "display_width"), &MobileVRInterface::set_display_width);
ClassDB::bind_method(D_METHOD("get_display_width"), &MobileVRInterface::get_display_width);
ClassDB::bind_method(D_METHOD("set_display_to_lens", "display_to_lens"), &MobileVRInterface::set_display_to_lens);
ClassDB::bind_method(D_METHOD("get_display_to_lens"), &MobileVRInterface::get_display_to_lens);
ClassDB::bind_method(D_METHOD("set_oversample", "oversample"), &MobileVRInterface::set_oversample);
ClassDB::bind_method(D_METHOD("get_oversample"), &MobileVRInterface::get_oversample);
ClassDB::bind_method(D_METHOD("set_k1", "k"), &MobileVRInterface::set_k1);
ClassDB::bind_method(D_METHOD("get_k1"), &MobileVRInterface::get_k1);
ClassDB::bind_method(D_METHOD("set_k2", "k"), &MobileVRInterface::set_k2);
ClassDB::bind_method(D_METHOD("get_k2"), &MobileVRInterface::get_k2);
ADD_PROPERTY(PropertyInfo(Variant::REAL, "eye_height", PROPERTY_HINT_RANGE, "0.0,3.0,0.1"), "set_eye_height", "get_eye_height");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "iod", PROPERTY_HINT_RANGE, "4.0,10.0,0.1"), "set_iod", "get_iod");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "display_width", PROPERTY_HINT_RANGE, "5.0,25.0,0.1"), "set_display_width", "get_display_width");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "display_to_lens", PROPERTY_HINT_RANGE, "5.0,25.0,0.1"), "set_display_to_lens", "get_display_to_lens");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "oversample", PROPERTY_HINT_RANGE, "1.0,2.0,0.1"), "set_oversample", "get_oversample");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "k1", PROPERTY_HINT_RANGE, "0.1,10.0,0.0001"), "set_k1", "get_k1");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "k2", PROPERTY_HINT_RANGE, "0.1,10.0,0.0001"), "set_k2", "get_k2");
}
void MobileVRInterface::set_eye_height(const real_t p_eye_height) {
eye_height = p_eye_height;
}
real_t MobileVRInterface::get_eye_height() const {
return eye_height;
}
void MobileVRInterface::set_iod(const real_t p_iod) {
intraocular_dist = p_iod;
};
real_t MobileVRInterface::get_iod() const {
return intraocular_dist;
};
void MobileVRInterface::set_display_width(const real_t p_display_width) {
display_width = p_display_width;
};
real_t MobileVRInterface::get_display_width() const {
return display_width;
};
void MobileVRInterface::set_display_to_lens(const real_t p_display_to_lens) {
display_to_lens = p_display_to_lens;
};
real_t MobileVRInterface::get_display_to_lens() const {
return display_to_lens;
};
void MobileVRInterface::set_oversample(const real_t p_oversample) {
oversample = p_oversample;
};
real_t MobileVRInterface::get_oversample() const {
return oversample;
};
void MobileVRInterface::set_k1(const real_t p_k1) {
k1 = p_k1;
};
real_t MobileVRInterface::get_k1() const {
return k1;
};
void MobileVRInterface::set_k2(const real_t p_k2) {
k2 = p_k2;
};
real_t MobileVRInterface::get_k2() const {
return k2;
};
bool MobileVRInterface::is_stereo() {
// needs stereo...
return true;
};
bool MobileVRInterface::is_initialized() const {
return (initialized);
};
bool MobileVRInterface::initialize() {
ARVRServer *arvr_server = ARVRServer::get_singleton();
ERR_FAIL_NULL_V(arvr_server, false);
if (!initialized) {
// reset our sensor data and orientation
mag_count = 0;
has_gyro = false;
sensor_first = true;
mag_next_min = Vector3(10000, 10000, 10000);
mag_next_max = Vector3(-10000, -10000, -10000);
mag_current_min = Vector3(0, 0, 0);
mag_current_max = Vector3(0, 0, 0);
// reset our orientation
orientation = Basis();
// make this our primary interface
arvr_server->set_primary_interface(this);
last_ticks = OS::get_singleton()->get_ticks_usec();
initialized = true;
};
return true;
};
void MobileVRInterface::uninitialize() {
if (initialized) {
ARVRServer *arvr_server = ARVRServer::get_singleton();
if (arvr_server != NULL) {
// no longer our primary interface
arvr_server->clear_primary_interface_if(this);
}
initialized = false;
};
};
Size2 MobileVRInterface::get_render_targetsize() {
_THREAD_SAFE_METHOD_
// we use half our window size
Size2 target_size = OS::get_singleton()->get_window_size();
target_size.x *= 0.5 * oversample;
target_size.y *= oversample;
return target_size;
};
Transform MobileVRInterface::get_transform_for_eye(ARVRInterface::Eyes p_eye, const Transform &p_cam_transform) {
_THREAD_SAFE_METHOD_
Transform transform_for_eye;
ARVRServer *arvr_server = ARVRServer::get_singleton();
ERR_FAIL_NULL_V(arvr_server, transform_for_eye);
if (initialized) {
float world_scale = arvr_server->get_world_scale();
// we don't need to check for the existence of our HMD, doesn't effect our values...
// note * 0.01 to convert cm to m and * 0.5 as we're moving half in each direction...
if (p_eye == ARVRInterface::EYE_LEFT) {
transform_for_eye.origin.x = -(intraocular_dist * 0.01 * 0.5 * world_scale);
} else if (p_eye == ARVRInterface::EYE_RIGHT) {
transform_for_eye.origin.x = intraocular_dist * 0.01 * 0.5 * world_scale;
} else {
// for mono we don't reposition, we want our center position.
};
// just scale our origin point of our transform
Transform hmd_transform;
hmd_transform.basis = orientation;
hmd_transform.origin = Vector3(0.0, eye_height * world_scale, 0.0);
transform_for_eye = p_cam_transform * (arvr_server->get_reference_frame()) * hmd_transform * transform_for_eye;
} else {
// huh? well just return what we got....
transform_for_eye = p_cam_transform;
};
return transform_for_eye;
};
CameraMatrix MobileVRInterface::get_projection_for_eye(ARVRInterface::Eyes p_eye, real_t p_aspect, real_t p_z_near, real_t p_z_far) {
_THREAD_SAFE_METHOD_
CameraMatrix eye;
if (p_eye == ARVRInterface::EYE_MONO) {
///@TODO for now hardcode some of this, what is really needed here is that this needs to be in sync with the real cameras properties
// which probably means implementing a specific class for iOS and Android. For now this is purely here as an example.
// Note also that if you use a normal viewport with AR/VR turned off you can still use the tracker output of this interface
// to position a stock standard Godot camera and have control over this.
// This will make more sense when we implement ARkit on iOS (probably a separate interface).
eye.set_perspective(60.0, p_aspect, p_z_near, p_z_far, false);
} else {
eye.set_for_hmd(p_eye == ARVRInterface::EYE_LEFT ? 1 : 2, p_aspect, intraocular_dist, display_width, display_to_lens, oversample, p_z_near, p_z_far);
};
return eye;
};
void MobileVRInterface::commit_for_eye(ARVRInterface::Eyes p_eye, RID p_render_target, const Rect2 &p_screen_rect) {
_THREAD_SAFE_METHOD_
// We must have a valid render target
ERR_FAIL_COND(!p_render_target.is_valid());
// Because we are rendering to our device we must use our main viewport!
ERR_FAIL_COND(p_screen_rect == Rect2());
Rect2 dest = p_screen_rect;
Vector2 eye_center;
// we output half a screen
dest.size.x *= 0.5;
if (p_eye == ARVRInterface::EYE_LEFT) {
eye_center.x = ((-intraocular_dist / 2.0) + (display_width / 4.0)) / (display_width / 2.0);
} else if (p_eye == ARVRInterface::EYE_RIGHT) {
dest.position.x = dest.size.x;
eye_center.x = ((intraocular_dist / 2.0) - (display_width / 4.0)) / (display_width / 2.0);
}
// we don't offset the eye center vertically (yet)
eye_center.y = 0.0;
// unset our render target so we are outputting to our main screen by making RasterizerStorageGLES3::system_fbo our current FBO
VSG::rasterizer->set_current_render_target(RID());
// and output
VSG::rasterizer->output_lens_distorted_to_screen(p_render_target, dest, k1, k2, eye_center, oversample);
};
void MobileVRInterface::process() {
_THREAD_SAFE_METHOD_
if (initialized) {
set_position_from_sensors();
};
};
void MobileVRInterface::notification(int p_what){
_THREAD_SAFE_METHOD_
// nothing to do here, I guess we could pauze our sensors...
}
MobileVRInterface::MobileVRInterface() {
initialized = false;
// Just set some defaults for these. At some point we need to look at adding a lookup table for common device + headset combos and/or support reading cardboard QR codes
eye_height = 1.85;
intraocular_dist = 6.0;
display_width = 14.5;
display_to_lens = 4.0;
oversample = 1.5;
k1 = 0.215;
k2 = 0.215;
last_ticks = 0;
};
MobileVRInterface::~MobileVRInterface() {
// and make sure we cleanup if we haven't already
if (is_initialized()) {
uninitialize();
};
};