Implement HID gamepad

Implement the HID protocol for gamepads, that will be used in further
commits by the AOA and UHID gamepad processor implementations.

PR #5270 <https://github.com/Genymobile/scrcpy/pull/5270>
This commit is contained in:
Romain Vimont 2024-09-06 23:08:08 +02:00
parent f4d1e49ad9
commit a59c6df4b7
4 changed files with 506 additions and 1 deletions

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@ -32,6 +32,7 @@ src = [
'src/screen.c',
'src/server.c',
'src/version.c',
'src/hid/hid_gamepad.c',
'src/hid/hid_keyboard.c',
'src/hid/hid_mouse.c',
'src/trait/frame_source.c',

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@ -5,7 +5,7 @@
#include <stdint.h>
#define SC_HID_MAX_SIZE 8
#define SC_HID_MAX_SIZE 15
struct sc_hid_input {
uint16_t hid_id;

451
app/src/hid/hid_gamepad.c Normal file
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@ -0,0 +1,451 @@
#include "hid_gamepad.h"
#include <assert.h>
#include <inttypes.h>
#include "util/binary.h"
#include "util/log.h"
// 2x2 bytes for left stick (X, Y)
// 2x2 bytes for right stick (Z, Rz)
// 2x2 bytes for L2/R2 triggers
// 2 bytes for buttons + padding,
// 1 byte for hat switch (dpad) + padding
#define SC_HID_GAMEPAD_EVENT_SIZE 15
// The ->buttons field stores the state for all buttons, but only some of them
// (the 16 LSB) must be transmitted "as is". The DPAD (hat switch) buttons are
// stored locally in the MSB of this field, but not transmitted as is: they are
// transformed to generate another specific byte.
#define SC_HID_BUTTONS_MASK 0xFFFF
// outside SC_HID_BUTTONS_MASK
#define SC_GAMEPAD_BUTTONS_BIT_DPAD_UP UINT32_C(0x10000)
#define SC_GAMEPAD_BUTTONS_BIT_DPAD_DOWN UINT32_C(0x20000)
#define SC_GAMEPAD_BUTTONS_BIT_DPAD_LEFT UINT32_C(0x40000)
#define SC_GAMEPAD_BUTTONS_BIT_DPAD_RIGHT UINT32_C(0x80000)
/**
* Gamepad descriptor manually crafted to transmit the input reports.
*
* The HID specification is available here:
* <https://www.usb.org/document-library/device-class-definition-hid-111>
*
* The HID Usage Tables is also useful:
* <https://www.usb.org/document-library/hid-usage-tables-15>
*/
static const uint8_t SC_HID_GAMEPAD_REPORT_DESC[] = {
// Usage Page (Generic Desktop)
0x05, 0x01,
// Usage (Gamepad)
0x09, 0x05,
// Collection (Application)
0xA1, 0x01,
// Collection (Physical)
0xA1, 0x00,
// Usage Page (Generic Desktop)
0x05, 0x01,
// Usage (X) Left stick x
0x09, 0x30,
// Usage (Y) Left stick y
0x09, 0x31,
// Usage (Z) Right stick x
0x09, 0x32,
// Usage (Rz) Right stick y
0x09, 0x35,
// Logical Minimum (0)
0x15, 0x00,
// Logical Maximum (65535)
// Cannot use 26 FF FF because 0xFFFF is interpreted as signed 16-bit
0x27, 0xFF, 0xFF, 0x00, 0x00, // little-endian
// Report Size (16)
0x75, 0x10,
// Report Count (4)
0x95, 0x04,
// Input (Data, Variable, Absolute): 4 bytes (X, Y, Z, Rz)
0x81, 0x02,
// Usage Page (Simulation Controls)
0x05, 0x02,
// Usage (Brake)
0x09, 0xC5,
// Usage (Accelerator)
0x09, 0xC4,
// Logical Minimum (0)
0x15, 0x00,
// Logical Maximum (32767)
0x26, 0xFF, 0x7F,
// Report Size (16)
0x75, 0x10,
// Report Count (2)
0x95, 0x02,
// Input (Data, Variable, Absolute): 2 bytes (L2, R2)
0x81, 0x02,
// Usage Page (Buttons)
0x05, 0x09,
// Usage Minimum (1)
0x19, 0x01,
// Usage Maximum (16)
0x29, 0x10,
// Logical Minimum (0)
0x15, 0x00,
// Logical Maximum (1)
0x25, 0x01,
// Report Count (16)
0x95, 0x10,
// Report Size (1)
0x75, 0x01,
// Input (Data, Variable, Absolute): 16 buttons bits
0x81, 0x02,
// Usage Page (Generic Desktop)
0x05, 0x01,
// Usage (Hat switch)
0x09, 0x39,
// Logical Minimum (1)
0x15, 0x01,
// Logical Maximum (8)
0x25, 0x08,
// Report Size (4)
0x75, 0x04,
// Report Count (1)
0x95, 0x01,
// Input (Data, Variable, Null State): 4-bit value
0x81, 0x42,
// End Collection
0xC0,
// End Collection
0xC0,
};
/**
* A gamepad HID input report is 15 bytes long:
* - bytes 0-3: left stick state
* - bytes 4-7: right stick state
* - bytes 8-11: L2/R2 triggers state
* - bytes 12-13: buttons state
* - bytes 14: hat switch position (dpad)
*
* +---------------+
* byte 0: |. . . . . . . .|
* | | left stick x (0-65535, little-endian)
* byte 1: |. . . . . . . .|
* +---------------+
* byte 2: |. . . . . . . .|
* | | left stick y (0-65535, little-endian)
* byte 3: |. . . . . . . .|
* +---------------+
* byte 4: |. . . . . . . .|
* | | right stick x (0-65535, little-endian)
* byte 5: |. . . . . . . .|
* +---------------+
* byte 6: |. . . . . . . .|
* | | right stick y (0-65535, little-endian)
* byte 7: |. . . . . . . .|
* +---------------+
* byte 8: |. . . . . . . .|
* | | L2 trigger (0-32767, little-endian)
* byte 9: |0 . . . . . . .|
* +---------------+
* byte 10: |. . . . . . . .|
* | | R2 trigger (0-32767, little-endian)
* byte 11: |0 . . . . . . .|
* +---------------+
*
* ,--------------- SC_GAMEPAD_BUTTON_RIGHT_SHOULDER
* | ,------------- SC_GAMEPAD_BUTTON_LEFT_SHOULDER
* | |
* | | ,--------- SC_GAMEPAD_BUTTON_NORTH
* | | | ,------- SC_GAMEPAD_BUTTON_WEST
* | | | |
* | | | | ,--- SC_GAMEPAD_BUTTON_EAST
* | | | | | ,- SC_GAMEPAD_BUTTON_SOUTH
* v v v v v v
* +---------------+
* byte 12: |. . 0 . . 0 . .|
* | | Buttons (16-bit little-endian)
* byte 13: |0 . . . . . 0 0|
* +---------------+
* ^ ^ ^ ^ ^
* | | | | |
* | | | | |
* | | | | `----- SC_GAMEPAD_BUTTON_BACK
* | | | `------- SC_GAMEPAD_BUTTON_START
* | | `--------- SC_GAMEPAD_BUTTON_GUIDE
* | `----------- SC_GAMEPAD_BUTTON_LEFT_STICK
* `------------- SC_GAMEPAD_BUTTON_RIGHT_STICK
*
* +---------------+
* byte 14: |0 0 0 . . . . .| hat switch (dpad) position (0-8)
* +---------------+
* 9 possible positions and their values:
* 8 1 2
* 7 0 3
* 6 5 4
* (8 is top-left, 1 is top, 2 is top-right, etc.)
*/
static void
sc_hid_gamepad_slot_init(struct sc_hid_gamepad_slot *slot,
uint32_t gamepad_id) {
assert(gamepad_id != SC_GAMEPAD_ID_INVALID);
slot->gamepad_id = gamepad_id;
slot->buttons = 0;
slot->axis_left_x = 0;
slot->axis_left_y = 0;
slot->axis_right_x = 0;
slot->axis_right_y = 0;
slot->axis_left_trigger = 0;
slot->axis_right_trigger = 0;
}
static ssize_t
sc_hid_gamepad_slot_find(struct sc_hid_gamepad *hid, uint32_t gamepad_id) {
for (size_t i = 0; i < SC_MAX_GAMEPADS; ++i) {
if (gamepad_id == hid->slots[i].gamepad_id) {
// found
return i;
}
}
return -1;
}
void
sc_hid_gamepad_init(struct sc_hid_gamepad *hid) {
for (size_t i = 0; i < SC_MAX_GAMEPADS; ++i) {
hid->slots[i].gamepad_id = SC_GAMEPAD_ID_INVALID;
}
}
static inline uint16_t
sc_hid_gamepad_slot_get_id(size_t slot_idx) {
assert(slot_idx < SC_MAX_GAMEPADS);
return SC_HID_ID_GAMEPAD_FIRST + slot_idx;
}
bool
sc_hid_gamepad_generate_open(struct sc_hid_gamepad *hid,
struct sc_hid_open *hid_open,
uint32_t gamepad_id) {
assert(gamepad_id != SC_GAMEPAD_ID_INVALID);
ssize_t slot_idx = sc_hid_gamepad_slot_find(hid, SC_GAMEPAD_ID_INVALID);
if (slot_idx == -1) {
LOGW("No gamepad slot available for new gamepad %" PRIu32, gamepad_id);
return false;
}
sc_hid_gamepad_slot_init(&hid->slots[slot_idx], gamepad_id);
uint16_t hid_id = sc_hid_gamepad_slot_get_id(slot_idx);
hid_open->hid_id = hid_id;
hid_open->report_desc = SC_HID_GAMEPAD_REPORT_DESC;
hid_open->report_desc_size = sizeof(SC_HID_GAMEPAD_REPORT_DESC);
return true;
}
bool
sc_hid_gamepad_generate_close(struct sc_hid_gamepad *hid,
struct sc_hid_close *hid_close,
uint32_t gamepad_id) {
assert(gamepad_id != SC_GAMEPAD_ID_INVALID);
ssize_t slot_idx = sc_hid_gamepad_slot_find(hid, gamepad_id);
if (slot_idx == -1) {
LOGW("Unknown gamepad removed %" PRIu32, gamepad_id);
return false;
}
hid->slots[slot_idx].gamepad_id = SC_GAMEPAD_ID_INVALID;
uint16_t hid_id = sc_hid_gamepad_slot_get_id(slot_idx);
hid_close->hid_id = hid_id;
return true;
}
static uint8_t
sc_hid_gamepad_get_dpad_value(uint32_t buttons) {
// Value depending on direction:
// 8 1 2
// 7 0 3
// 6 5 4
if (buttons & SC_GAMEPAD_BUTTONS_BIT_DPAD_UP) {
if (buttons & SC_GAMEPAD_BUTTONS_BIT_DPAD_LEFT) {
return 8;
}
if (buttons & SC_GAMEPAD_BUTTONS_BIT_DPAD_RIGHT) {
return 2;
}
return 1;
}
if (buttons & SC_GAMEPAD_BUTTONS_BIT_DPAD_DOWN) {
if (buttons & SC_GAMEPAD_BUTTONS_BIT_DPAD_LEFT) {
return 6;
}
if (buttons & SC_GAMEPAD_BUTTONS_BIT_DPAD_RIGHT) {
return 4;
}
return 5;
}
if (buttons & SC_GAMEPAD_BUTTONS_BIT_DPAD_LEFT) {
return 7;
}
if (buttons & SC_GAMEPAD_BUTTONS_BIT_DPAD_RIGHT) {
return 3;
}
return 0;
}
static void
sc_hid_gamepad_event_from_slot(uint16_t hid_id,
const struct sc_hid_gamepad_slot *slot,
struct sc_hid_input *hid_input) {
hid_input->hid_id = hid_id;
hid_input->size = SC_HID_GAMEPAD_EVENT_SIZE;
uint8_t *data = hid_input->data;
// Values must be written in little-endian
sc_write16le(data, slot->axis_left_x);
sc_write16le(data + 2, slot->axis_left_y);
sc_write16le(data + 4, slot->axis_right_x);
sc_write16le(data + 6, slot->axis_right_y);
sc_write16le(data + 8, slot->axis_left_trigger);
sc_write16le(data + 10, slot->axis_right_trigger);
sc_write16le(data + 12, slot->buttons & SC_HID_BUTTONS_MASK);
data[14] = sc_hid_gamepad_get_dpad_value(slot->buttons);
}
static uint32_t
sc_hid_gamepad_get_button_id(enum sc_gamepad_button button) {
switch (button) {
case SC_GAMEPAD_BUTTON_SOUTH:
return 0x0001;
case SC_GAMEPAD_BUTTON_EAST:
return 0x0002;
case SC_GAMEPAD_BUTTON_WEST:
return 0x0008;
case SC_GAMEPAD_BUTTON_NORTH:
return 0x0010;
case SC_GAMEPAD_BUTTON_BACK:
return 0x0400;
case SC_GAMEPAD_BUTTON_GUIDE:
return 0x1000;
case SC_GAMEPAD_BUTTON_START:
return 0x0800;
case SC_GAMEPAD_BUTTON_LEFT_STICK:
return 0x2000;
case SC_GAMEPAD_BUTTON_RIGHT_STICK:
return 0x4000;
case SC_GAMEPAD_BUTTON_LEFT_SHOULDER:
return 0x0040;
case SC_GAMEPAD_BUTTON_RIGHT_SHOULDER:
return 0x0080;
case SC_GAMEPAD_BUTTON_DPAD_UP:
return SC_GAMEPAD_BUTTONS_BIT_DPAD_UP;
case SC_GAMEPAD_BUTTON_DPAD_DOWN:
return SC_GAMEPAD_BUTTONS_BIT_DPAD_DOWN;
case SC_GAMEPAD_BUTTON_DPAD_LEFT:
return SC_GAMEPAD_BUTTONS_BIT_DPAD_LEFT;
case SC_GAMEPAD_BUTTON_DPAD_RIGHT:
return SC_GAMEPAD_BUTTONS_BIT_DPAD_RIGHT;
default:
// unknown button, ignore
return 0;
}
}
bool
sc_hid_gamepad_generate_input_from_button(struct sc_hid_gamepad *hid,
struct sc_hid_input *hid_input,
const struct sc_gamepad_button_event *event) {
if ((event->button < 0) || (event->button > 15)) {
return false;
}
uint32_t gamepad_id = event->gamepad_id;
ssize_t slot_idx = sc_hid_gamepad_slot_find(hid, gamepad_id);
if (slot_idx == -1) {
LOGW("Axis event for unknown gamepad %" PRIu32, gamepad_id);
return false;
}
assert(slot_idx < SC_MAX_GAMEPADS);
struct sc_hid_gamepad_slot *slot = &hid->slots[slot_idx];
uint32_t button = sc_hid_gamepad_get_button_id(event->button);
if (!button) {
// unknown button, ignore
return false;
}
if (event->action == SC_ACTION_DOWN) {
slot->buttons |= button;
} else {
assert(event->action == SC_ACTION_UP);
slot->buttons &= ~button;
}
uint16_t hid_id = sc_hid_gamepad_slot_get_id(slot_idx);
sc_hid_gamepad_event_from_slot(hid_id, slot, hid_input);
return true;
}
bool
sc_hid_gamepad_generate_input_from_axis(struct sc_hid_gamepad *hid,
struct sc_hid_input *hid_input,
const struct sc_gamepad_axis_event *event) {
uint32_t gamepad_id = event->gamepad_id;
ssize_t slot_idx = sc_hid_gamepad_slot_find(hid, gamepad_id);
if (slot_idx == -1) {
LOGW("Button event for unknown gamepad %" PRIu32, gamepad_id);
return false;
}
assert(slot_idx < SC_MAX_GAMEPADS);
struct sc_hid_gamepad_slot *slot = &hid->slots[slot_idx];
// [-32768 to 32767] -> [0 to 65535]
#define AXIS_RESCALE(V) (uint16_t) (((int32_t) V) + 0x8000)
switch (event->axis) {
case SC_GAMEPAD_AXIS_LEFTX:
slot->axis_left_x = AXIS_RESCALE(event->value);
break;
case SC_GAMEPAD_AXIS_LEFTY:
slot->axis_left_y = AXIS_RESCALE(event->value);
break;
case SC_GAMEPAD_AXIS_RIGHTX:
slot->axis_right_x = AXIS_RESCALE(event->value);
break;
case SC_GAMEPAD_AXIS_RIGHTY:
slot->axis_right_y = AXIS_RESCALE(event->value);
break;
case SC_GAMEPAD_AXIS_LEFT_TRIGGER:
// Trigger is always positive between 0 and 32767
slot->axis_left_trigger = MAX(0, event->value);
break;
case SC_GAMEPAD_AXIS_RIGHT_TRIGGER:
// Trigger is always positive between 0 and 32767
slot->axis_right_trigger = MAX(0, event->value);
break;
default:
return false;
}
uint16_t hid_id = sc_hid_gamepad_slot_get_id(slot_idx);
sc_hid_gamepad_event_from_slot(hid_id, slot, hid_input);
return true;
}

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app/src/hid/hid_gamepad.h Normal file
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@ -0,0 +1,53 @@
#ifndef SC_HID_GAMEPAD_H
#define SC_HID_GAMEPAD_H
#include "common.h"
#include <stdbool.h>
#include "hid/hid_event.h"
#include "input_events.h"
#define SC_MAX_GAMEPADS 8
#define SC_HID_ID_GAMEPAD_FIRST 3
#define SC_HID_ID_GAMEPAD_LAST (SC_HID_ID_GAMEPAD_FIRST + SC_MAX_GAMEPADS - 1)
struct sc_hid_gamepad_slot {
uint32_t gamepad_id;
uint32_t buttons;
uint16_t axis_left_x;
uint16_t axis_left_y;
uint16_t axis_right_x;
uint16_t axis_right_y;
uint16_t axis_left_trigger;
uint16_t axis_right_trigger;
};
struct sc_hid_gamepad {
struct sc_hid_gamepad_slot slots[SC_MAX_GAMEPADS];
};
void
sc_hid_gamepad_init(struct sc_hid_gamepad *hid);
bool
sc_hid_gamepad_generate_open(struct sc_hid_gamepad *hid,
struct sc_hid_open *hid_open,
uint32_t gamepad_id);
bool
sc_hid_gamepad_generate_close(struct sc_hid_gamepad *hid,
struct sc_hid_close *hid_close,
uint32_t gamepad_id);
bool
sc_hid_gamepad_generate_input_from_button(struct sc_hid_gamepad *hid,
struct sc_hid_input *hid_input,
const struct sc_gamepad_button_event *event);
bool
sc_hid_gamepad_generate_input_from_axis(struct sc_hid_gamepad *hid,
struct sc_hid_input *hid_input,
const struct sc_gamepad_axis_event *event);
#endif