1/**************************************************************************/
2/* mobile_vr_interface.cpp */
3/**************************************************************************/
4/* This file is part of: */
5/* GODOT ENGINE */
6/* https://godotengine.org */
7/**************************************************************************/
8/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
9/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
10/* */
11/* Permission is hereby granted, free of charge, to any person obtaining */
12/* a copy of this software and associated documentation files (the */
13/* "Software"), to deal in the Software without restriction, including */
14/* without limitation the rights to use, copy, modify, merge, publish, */
15/* distribute, sublicense, and/or sell copies of the Software, and to */
16/* permit persons to whom the Software is furnished to do so, subject to */
17/* the following conditions: */
18/* */
19/* The above copyright notice and this permission notice shall be */
20/* included in all copies or substantial portions of the Software. */
21/* */
22/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
23/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
24/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
25/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
26/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
27/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
28/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
29/**************************************************************************/
30
31#include "mobile_vr_interface.h"
32
33#include "core/input/input.h"
34#include "core/os/os.h"
35#include "servers/display_server.h"
36#include "servers/rendering/rendering_server_globals.h"
37
38StringName MobileVRInterface::get_name() const {
39 return "Native mobile";
40};
41
42uint32_t MobileVRInterface::get_capabilities() const {
43 return XRInterface::XR_STEREO;
44};
45
46Vector3 MobileVRInterface::scale_magneto(const Vector3 &p_magnetometer) {
47 // Our magnetometer doesn't give us nice clean data.
48 // Well it may on macOS because we're getting a calibrated value in the current implementation but Android we're getting raw data.
49 // This is a fairly simple adjustment we can do to correct for the magnetometer data being elliptical
50
51 Vector3 mag_raw = p_magnetometer;
52 Vector3 mag_scaled = p_magnetometer;
53
54 // update our variables every x frames
55 if (mag_count > 20) {
56 mag_current_min = mag_next_min;
57 mag_current_max = mag_next_max;
58 mag_count = 0;
59 } else {
60 mag_count++;
61 };
62
63 // adjust our min and max
64 if (mag_raw.x > mag_next_max.x) {
65 mag_next_max.x = mag_raw.x;
66 }
67 if (mag_raw.y > mag_next_max.y) {
68 mag_next_max.y = mag_raw.y;
69 }
70 if (mag_raw.z > mag_next_max.z) {
71 mag_next_max.z = mag_raw.z;
72 }
73
74 if (mag_raw.x < mag_next_min.x) {
75 mag_next_min.x = mag_raw.x;
76 }
77 if (mag_raw.y < mag_next_min.y) {
78 mag_next_min.y = mag_raw.y;
79 }
80 if (mag_raw.z < mag_next_min.z) {
81 mag_next_min.z = mag_raw.z;
82 }
83
84 // scale our x, y and z
85 if (!(mag_current_max.x - mag_current_min.x)) {
86 mag_raw.x -= (mag_current_min.x + mag_current_max.x) / 2.0;
87 mag_scaled.x = (mag_raw.x - mag_current_min.x) / ((mag_current_max.x - mag_current_min.x) * 2.0 - 1.0);
88 };
89
90 if (!(mag_current_max.y - mag_current_min.y)) {
91 mag_raw.y -= (mag_current_min.y + mag_current_max.y) / 2.0;
92 mag_scaled.y = (mag_raw.y - mag_current_min.y) / ((mag_current_max.y - mag_current_min.y) * 2.0 - 1.0);
93 };
94
95 if (!(mag_current_max.z - mag_current_min.z)) {
96 mag_raw.z -= (mag_current_min.z + mag_current_max.z) / 2.0;
97 mag_scaled.z = (mag_raw.z - mag_current_min.z) / ((mag_current_max.z - mag_current_min.z) * 2.0 - 1.0);
98 };
99
100 return mag_scaled;
101};
102
103Basis MobileVRInterface::combine_acc_mag(const Vector3 &p_grav, const Vector3 &p_magneto) {
104 // yup, stock standard cross product solution...
105 Vector3 up = -p_grav.normalized();
106
107 Vector3 magneto_east = up.cross(p_magneto.normalized()); // or is this west?, but should be horizon aligned now
108 magneto_east.normalize();
109
110 Vector3 magneto = up.cross(magneto_east); // and now we have a horizon aligned north
111 magneto.normalize();
112
113 // We use our gravity and magnetometer vectors to construct our matrix
114 Basis acc_mag_m3;
115 acc_mag_m3.rows[0] = -magneto_east;
116 acc_mag_m3.rows[1] = up;
117 acc_mag_m3.rows[2] = magneto;
118
119 return acc_mag_m3;
120};
121
122void MobileVRInterface::set_position_from_sensors() {
123 _THREAD_SAFE_METHOD_
124
125 // this is a helper function that attempts to adjust our transform using our 9dof sensors
126 // 9dof is a misleading marketing term coming from 3 accelerometer axis + 3 gyro axis + 3 magnetometer axis = 9 axis
127 // but in reality this only offers 3 dof (yaw, pitch, roll) orientation
128
129 Basis orientation;
130
131 uint64_t ticks = OS::get_singleton()->get_ticks_usec();
132 uint64_t ticks_elapsed = ticks - last_ticks;
133 float delta_time = (double)ticks_elapsed / 1000000.0;
134
135 // few things we need
136 Input *input = Input::get_singleton();
137 Vector3 down(0.0, -1.0, 0.0); // Down is Y negative
138 Vector3 north(0.0, 0.0, 1.0); // North is Z positive
139
140 // make copies of our inputs
141 bool has_grav = false;
142 Vector3 acc = input->get_accelerometer();
143 Vector3 gyro = input->get_gyroscope();
144 Vector3 grav = input->get_gravity();
145 Vector3 magneto = scale_magneto(input->get_magnetometer()); // this may be overkill on iOS because we're already getting a calibrated magnetometer reading
146
147 if (sensor_first) {
148 sensor_first = false;
149 } else {
150 acc = scrub(acc, last_accerometer_data, 2, 0.2);
151 magneto = scrub(magneto, last_magnetometer_data, 3, 0.3);
152 };
153
154 last_accerometer_data = acc;
155 last_magnetometer_data = magneto;
156
157 if (grav.length() < 0.1) {
158 // not ideal but use our accelerometer, this will contain shaky user behavior
159 // maybe look into some math but I'm guessing that if this isn't available, it's because we lack the gyro sensor to actually work out
160 // what a stable gravity vector is
161 grav = acc;
162 if (grav.length() > 0.1) {
163 has_grav = true;
164 };
165 } else {
166 has_grav = true;
167 };
168
169 bool has_magneto = magneto.length() > 0.1;
170 if (gyro.length() > 0.1) {
171 /* this can return to 0.0 if the user doesn't move the phone, so once on, it's on */
172 has_gyro = true;
173 };
174
175 if (has_gyro) {
176 // start with applying our gyro (do NOT smooth our gyro!)
177 Basis rotate;
178 rotate.rotate(orientation.get_column(0), gyro.x * delta_time);
179 rotate.rotate(orientation.get_column(1), gyro.y * delta_time);
180 rotate.rotate(orientation.get_column(2), gyro.z * delta_time);
181 orientation = rotate * orientation;
182
183 tracking_state = XRInterface::XR_NORMAL_TRACKING;
184 tracking_confidence = XRPose::XR_TRACKING_CONFIDENCE_HIGH;
185 };
186
187 ///@TODO improve this, the magnetometer is very fidgety sometimes flipping the axis for no apparent reason (probably a bug on my part)
188 // if you have a gyro + accelerometer that combo tends to be better than combining all three but without a gyro you need the magnetometer..
189 if (has_magneto && has_grav && !has_gyro) {
190 // convert to quaternions, easier to smooth those out
191 Quaternion transform_quat(orientation);
192 Quaternion acc_mag_quat(combine_acc_mag(grav, magneto));
193 transform_quat = transform_quat.slerp(acc_mag_quat, 0.1);
194 orientation = Basis(transform_quat);
195
196 tracking_state = XRInterface::XR_NORMAL_TRACKING;
197 tracking_confidence = XRPose::XR_TRACKING_CONFIDENCE_HIGH;
198 } else if (has_grav) {
199 // use gravity vector to make sure down is down...
200 // transform gravity into our world space
201 grav.normalize();
202 Vector3 grav_adj = orientation.xform(grav);
203 float dot = grav_adj.dot(down);
204 if ((dot > -1.0) && (dot < 1.0)) {
205 // axis around which we have this rotation
206 Vector3 axis = grav_adj.cross(down);
207 axis.normalize();
208
209 Basis drift_compensation(axis, acos(dot) * delta_time * 10);
210 orientation = drift_compensation * orientation;
211 };
212 };
213
214 // and copy to our head transform
215 head_transform.basis = orientation.orthonormalized();
216
217 last_ticks = ticks;
218};
219
220void MobileVRInterface::_bind_methods() {
221 ClassDB::bind_method(D_METHOD("set_eye_height", "eye_height"), &MobileVRInterface::set_eye_height);
222 ClassDB::bind_method(D_METHOD("get_eye_height"), &MobileVRInterface::get_eye_height);
223
224 ClassDB::bind_method(D_METHOD("set_iod", "iod"), &MobileVRInterface::set_iod);
225 ClassDB::bind_method(D_METHOD("get_iod"), &MobileVRInterface::get_iod);
226
227 ClassDB::bind_method(D_METHOD("set_display_width", "display_width"), &MobileVRInterface::set_display_width);
228 ClassDB::bind_method(D_METHOD("get_display_width"), &MobileVRInterface::get_display_width);
229
230 ClassDB::bind_method(D_METHOD("set_display_to_lens", "display_to_lens"), &MobileVRInterface::set_display_to_lens);
231 ClassDB::bind_method(D_METHOD("get_display_to_lens"), &MobileVRInterface::get_display_to_lens);
232
233 ClassDB::bind_method(D_METHOD("set_oversample", "oversample"), &MobileVRInterface::set_oversample);
234 ClassDB::bind_method(D_METHOD("get_oversample"), &MobileVRInterface::get_oversample);
235
236 ClassDB::bind_method(D_METHOD("set_k1", "k"), &MobileVRInterface::set_k1);
237 ClassDB::bind_method(D_METHOD("get_k1"), &MobileVRInterface::get_k1);
238
239 ClassDB::bind_method(D_METHOD("set_k2", "k"), &MobileVRInterface::set_k2);
240 ClassDB::bind_method(D_METHOD("get_k2"), &MobileVRInterface::get_k2);
241
242 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "eye_height", PROPERTY_HINT_RANGE, "0.0,3.0,0.1"), "set_eye_height", "get_eye_height");
243 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "iod", PROPERTY_HINT_RANGE, "4.0,10.0,0.1"), "set_iod", "get_iod");
244 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "display_width", PROPERTY_HINT_RANGE, "5.0,25.0,0.1"), "set_display_width", "get_display_width");
245 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "display_to_lens", PROPERTY_HINT_RANGE, "5.0,25.0,0.1"), "set_display_to_lens", "get_display_to_lens");
246 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "oversample", PROPERTY_HINT_RANGE, "1.0,2.0,0.1"), "set_oversample", "get_oversample");
247 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "k1", PROPERTY_HINT_RANGE, "0.1,10.0,0.0001"), "set_k1", "get_k1");
248 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "k2", PROPERTY_HINT_RANGE, "0.1,10.0,0.0001"), "set_k2", "get_k2");
249}
250
251void MobileVRInterface::set_eye_height(const double p_eye_height) {
252 eye_height = p_eye_height;
253}
254
255double MobileVRInterface::get_eye_height() const {
256 return eye_height;
257}
258
259void MobileVRInterface::set_iod(const double p_iod) {
260 intraocular_dist = p_iod;
261};
262
263double MobileVRInterface::get_iod() const {
264 return intraocular_dist;
265};
266
267void MobileVRInterface::set_display_width(const double p_display_width) {
268 display_width = p_display_width;
269};
270
271double MobileVRInterface::get_display_width() const {
272 return display_width;
273};
274
275void MobileVRInterface::set_display_to_lens(const double p_display_to_lens) {
276 display_to_lens = p_display_to_lens;
277};
278
279double MobileVRInterface::get_display_to_lens() const {
280 return display_to_lens;
281};
282
283void MobileVRInterface::set_oversample(const double p_oversample) {
284 oversample = p_oversample;
285};
286
287double MobileVRInterface::get_oversample() const {
288 return oversample;
289};
290
291void MobileVRInterface::set_k1(const double p_k1) {
292 k1 = p_k1;
293};
294
295double MobileVRInterface::get_k1() const {
296 return k1;
297};
298
299void MobileVRInterface::set_k2(const double p_k2) {
300 k2 = p_k2;
301};
302
303double MobileVRInterface::get_k2() const {
304 return k2;
305};
306
307uint32_t MobileVRInterface::get_view_count() {
308 // needs stereo...
309 return 2;
310};
311
312XRInterface::TrackingStatus MobileVRInterface::get_tracking_status() const {
313 return tracking_state;
314}
315
316bool MobileVRInterface::is_initialized() const {
317 return (initialized);
318};
319
320bool MobileVRInterface::initialize() {
321 XRServer *xr_server = XRServer::get_singleton();
322 ERR_FAIL_NULL_V(xr_server, false);
323
324 if (!initialized) {
325 // reset our sensor data
326 mag_count = 0;
327 has_gyro = false;
328 sensor_first = true;
329 mag_next_min = Vector3(10000, 10000, 10000);
330 mag_next_max = Vector3(-10000, -10000, -10000);
331 mag_current_min = Vector3(0, 0, 0);
332 mag_current_max = Vector3(0, 0, 0);
333 head_transform.basis = Basis();
334 head_transform.origin = Vector3(0.0, eye_height, 0.0);
335
336 // we must create a tracker for our head
337 head.instantiate();
338 head->set_tracker_type(XRServer::TRACKER_HEAD);
339 head->set_tracker_name("head");
340 head->set_tracker_desc("Players head");
341 xr_server->add_tracker(head);
342
343 // make this our primary interface
344 xr_server->set_primary_interface(this);
345
346 last_ticks = OS::get_singleton()->get_ticks_usec();
347
348 initialized = true;
349 };
350
351 return true;
352};
353
354void MobileVRInterface::uninitialize() {
355 if (initialized) {
356 // do any cleanup here...
357 XRServer *xr_server = XRServer::get_singleton();
358 if (xr_server != nullptr) {
359 if (head.is_valid()) {
360 xr_server->remove_tracker(head);
361
362 head.unref();
363 }
364
365 if (xr_server->get_primary_interface() == this) {
366 // no longer our primary interface
367 xr_server->set_primary_interface(nullptr);
368 }
369 }
370
371 initialized = false;
372 };
373};
374
375Dictionary MobileVRInterface::get_system_info() {
376 Dictionary dict;
377
378 dict[SNAME("XRRuntimeName")] = String("Godot mobile VR interface");
379 dict[SNAME("XRRuntimeVersion")] = String("");
380
381 return dict;
382}
383
384bool MobileVRInterface::supports_play_area_mode(XRInterface::PlayAreaMode p_mode) {
385 // This interface has no positional tracking so fix this to 3DOF
386 return p_mode == XR_PLAY_AREA_3DOF;
387}
388
389XRInterface::PlayAreaMode MobileVRInterface::get_play_area_mode() const {
390 return XR_PLAY_AREA_3DOF;
391}
392
393bool MobileVRInterface::set_play_area_mode(XRInterface::PlayAreaMode p_mode) {
394 return p_mode == XR_PLAY_AREA_3DOF;
395}
396
397Size2 MobileVRInterface::get_render_target_size() {
398 _THREAD_SAFE_METHOD_
399
400 // we use half our window size
401 Size2 target_size = DisplayServer::get_singleton()->window_get_size();
402
403 target_size.x *= 0.5 * oversample;
404 target_size.y *= oversample;
405
406 return target_size;
407};
408
409Transform3D MobileVRInterface::get_camera_transform() {
410 _THREAD_SAFE_METHOD_
411
412 Transform3D transform_for_eye;
413
414 XRServer *xr_server = XRServer::get_singleton();
415 ERR_FAIL_NULL_V(xr_server, transform_for_eye);
416
417 if (initialized) {
418 float world_scale = xr_server->get_world_scale();
419
420 // just scale our origin point of our transform
421 Transform3D _head_transform = head_transform;
422 _head_transform.origin *= world_scale;
423
424 transform_for_eye = (xr_server->get_reference_frame()) * _head_transform;
425 }
426
427 return transform_for_eye;
428};
429
430Transform3D MobileVRInterface::get_transform_for_view(uint32_t p_view, const Transform3D &p_cam_transform) {
431 _THREAD_SAFE_METHOD_
432
433 Transform3D transform_for_eye;
434
435 XRServer *xr_server = XRServer::get_singleton();
436 ERR_FAIL_NULL_V(xr_server, transform_for_eye);
437
438 if (initialized) {
439 float world_scale = xr_server->get_world_scale();
440
441 // we don't need to check for the existence of our HMD, doesn't affect our values...
442 // note * 0.01 to convert cm to m and * 0.5 as we're moving half in each direction...
443 if (p_view == 0) {
444 transform_for_eye.origin.x = -(intraocular_dist * 0.01 * 0.5 * world_scale);
445 } else if (p_view == 1) {
446 transform_for_eye.origin.x = intraocular_dist * 0.01 * 0.5 * world_scale;
447 } else {
448 // should not have any other values..
449 };
450
451 // just scale our origin point of our transform
452 Transform3D _head_transform = head_transform;
453 _head_transform.origin *= world_scale;
454
455 transform_for_eye = p_cam_transform * (xr_server->get_reference_frame()) * _head_transform * transform_for_eye;
456 } else {
457 // huh? well just return what we got....
458 transform_for_eye = p_cam_transform;
459 };
460
461 return transform_for_eye;
462};
463
464Projection MobileVRInterface::get_projection_for_view(uint32_t p_view, double p_aspect, double p_z_near, double p_z_far) {
465 _THREAD_SAFE_METHOD_
466
467 Projection eye;
468
469 aspect = p_aspect;
470 eye.set_for_hmd(p_view + 1, p_aspect, intraocular_dist, display_width, display_to_lens, oversample, p_z_near, p_z_far);
471
472 return eye;
473};
474
475Vector<BlitToScreen> MobileVRInterface::post_draw_viewport(RID p_render_target, const Rect2 &p_screen_rect) {
476 _THREAD_SAFE_METHOD_
477
478 Vector<BlitToScreen> blit_to_screen;
479
480 // We must have a valid render target
481 ERR_FAIL_COND_V(!p_render_target.is_valid(), blit_to_screen);
482
483 // Because we are rendering to our device we must use our main viewport!
484 ERR_FAIL_COND_V(p_screen_rect == Rect2(), blit_to_screen);
485
486 // and add our blits
487 BlitToScreen blit;
488 blit.render_target = p_render_target;
489 blit.multi_view.use_layer = true;
490 blit.lens_distortion.apply = true;
491 blit.lens_distortion.k1 = k1;
492 blit.lens_distortion.k2 = k2;
493 blit.lens_distortion.upscale = oversample;
494 blit.lens_distortion.aspect_ratio = aspect;
495
496 // left eye
497 blit.dst_rect = p_screen_rect;
498 blit.dst_rect.size.width *= 0.5;
499 blit.multi_view.layer = 0;
500 blit.lens_distortion.eye_center.x = ((-intraocular_dist / 2.0) + (display_width / 4.0)) / (display_width / 2.0);
501 blit_to_screen.push_back(blit);
502
503 // right eye
504 blit.dst_rect = p_screen_rect;
505 blit.dst_rect.size.width *= 0.5;
506 blit.dst_rect.position.x = blit.dst_rect.size.width;
507 blit.multi_view.layer = 1;
508 blit.lens_distortion.eye_center.x = ((intraocular_dist / 2.0) - (display_width / 4.0)) / (display_width / 2.0);
509 blit_to_screen.push_back(blit);
510
511 return blit_to_screen;
512}
513
514void MobileVRInterface::process() {
515 _THREAD_SAFE_METHOD_
516
517 if (initialized) {
518 // update our head transform orientation
519 set_position_from_sensors();
520
521 // update our head transform position (should be constant)
522 head_transform.origin = Vector3(0.0, eye_height, 0.0);
523
524 if (head.is_valid()) {
525 // Set our head position, note in real space, reference frame and world scale is applied later
526 head->set_pose("default", head_transform, Vector3(), Vector3(), tracking_confidence);
527 }
528 };
529};
530
531MobileVRInterface::MobileVRInterface() {}
532
533MobileVRInterface::~MobileVRInterface() {
534 // and make sure we cleanup if we haven't already
535 if (is_initialized()) {
536 uninitialize();
537 };
538};
539