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1 // Copyright (c) 2015 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2015 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "device/gamepad/gamepad_data_fetcher.h" | 5 #include "device/gamepad/gamepad_data_fetcher.h" |
6 | 6 |
7 #include <stddef.h> | |
8 #include <string.h> | |
9 | |
10 #include <cmath> | |
11 | |
12 #include "base/logging.h" | |
13 #include "build/build_config.h" | |
14 | |
15 namespace { | |
16 | |
17 #if !defined(OS_ANDROID) | |
18 const float kMinAxisResetValue = 0.1f; | |
19 #endif | |
20 | |
21 } // namespace | |
22 | |
23 namespace device { | 7 namespace device { |
24 | 8 |
25 using blink::WebGamepad; | 9 GamepadDataFetcher::GamepadDataFetcher() : provider_(nullptr) {} |
26 using blink::WebGamepads; | |
27 | 10 |
28 #if !defined(OS_ANDROID) | 11 void GamepadDataFetcher::InitializeProvider(GamepadProvider* provider) { |
29 void GamepadDataFetcher::MapAndSanitizeGamepadData(PadState* pad_state, | 12 DCHECK(provider); |
30 WebGamepad* pad) { | |
31 DCHECK(pad_state); | |
32 DCHECK(pad); | |
33 | 13 |
34 if (!pad_state->data.connected) { | 14 provider_ = provider; |
35 memset(pad, 0, sizeof(WebGamepad)); | 15 OnAddedToProvider(); |
36 return; | 16 } |
37 } | |
38 | 17 |
39 // Copy the current state to the output buffer, using the mapping | 18 GamepadDataFetcherFactory::GamepadDataFetcherFactory() {} |
40 // function, if there is one available. | |
41 if (pad_state->mapper) | |
42 pad_state->mapper(pad_state->data, pad); | |
43 else | |
44 *pad = pad_state->data; | |
45 | |
46 // About sanitization: Gamepads may report input event if the user is not | |
47 // interacting with it, due to hardware problems or environmental ones (pad | |
48 // has something heavy leaning against an axis.) This may cause user gestures | |
49 // to be detected erroniously, exposing gamepad information when the user had | |
50 // no intention of doing so. To avoid this we require that each button or axis | |
51 // report being at rest (zero) at least once before exposing its value to the | |
52 // Gamepad API. This state is tracked by the axis_mask and button_mask | |
53 // bitfields. If the bit for an axis or button is 0 it means the axis has | |
54 // never reported being at rest, and the value will be forced to zero. | |
55 | |
56 // We can skip axis sanitation if all available axes have been masked. | |
57 uint32_t full_axis_mask = (1 << pad->axesLength) - 1; | |
58 if (pad_state->axis_mask != full_axis_mask) { | |
59 for (size_t axis = 0; axis < pad->axesLength; ++axis) { | |
60 if (!(pad_state->axis_mask & 1 << axis)) { | |
61 if (fabs(pad->axes[axis]) < kMinAxisResetValue) { | |
62 pad_state->axis_mask |= 1 << axis; | |
63 } else { | |
64 pad->axes[axis] = 0.0f; | |
65 } | |
66 } | |
67 } | |
68 } | |
69 | |
70 // We can skip button sanitation if all available buttons have been masked. | |
71 uint32_t full_button_mask = (1 << pad->buttonsLength) - 1; | |
72 if (pad_state->button_mask != full_button_mask) { | |
73 for (size_t button = 0; button < pad->buttonsLength; ++button) { | |
74 if (!(pad_state->button_mask & 1 << button)) { | |
75 if (!pad->buttons[button].pressed) { | |
76 pad_state->button_mask |= 1 << button; | |
77 } else { | |
78 pad->buttons[button].pressed = false; | |
79 pad->buttons[button].value = 0.0f; | |
80 } | |
81 } | |
82 } | |
83 } | |
84 } | |
85 #endif | |
86 | 19 |
87 } // namespace device | 20 } // namespace device |
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