Introduce mouse velocity vector

For more smooth movement, let the firmware
calculate x,y movement over timer based
on a velocity vector given to a newly
introduced velocityXY GATT characteristic

src/main.c

@@ -7,16 +7,16 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include <zephyr.h>
+#include <zephyr/kernel.h>
 
-#include <usb/usb_device.h>
-#include <usb/class/usb_hid.h>
+#include <zephyr/usb/usb_device.h>
+#include <zephyr/usb/class/usb_hid.h>
 
-#include <bluetooth/bluetooth.h>
-#include <bluetooth/conn.h>
-#include <bluetooth/gatt.h>
-#include <bluetooth/hci.h>
-#include <bluetooth/uuid.h>
+#include <zephyr/bluetooth/bluetooth.h>
+#include <zephyr/bluetooth/conn.h>
+#include <zephyr/bluetooth/gatt.h>
+#include <zephyr/bluetooth/hci.h>
+#include <zephyr/bluetooth/uuid.h>
 
 #include "simplems.h"
 
@@ -82,8 +82,52 @@ static void sm_buttons_cb(uint8_t buttons)
 	}
 }
 
+// Velocity is ~ *2 px/s
+static int32_t _dx;
+static int32_t _dy;
+static int16_t _vx;
+static int16_t _vy;
+
+static void sm_velocity_xy_cb(int16_t vx, int16_t vy) {
+	printk("Velocity (x,y) = (%d, %d)\n", vx, vy);
+
+	_vx = vx;
+	_vy = vy;
+}
+
+#define ABS(x)	(x > 0 ? x : -x)
+
+static int16_t overflow(uint32_t *delta, uint16_t velocity)
+{
+	int16_t overflow;
+	*delta += velocity;
+
+	overflow = *delta / 256;
+
+	*delta = *delta % 0xff;
+
+	return overflow;
+}
+
+void apply_velocity(struct k_timer *dummy)
+{
+	int8_t mx;
+	int8_t my;
+
+	mx = (int8_t)overflow(&_dx, _vx);
+	my = (int8_t)overflow(&_dy, _vy);
+
+	if (mx || my) {
+		sm_move_xy_cb(mx, my);
+	}
+}
+
+K_TIMER_DEFINE(velocity_timer, apply_velocity, NULL);
+
+
 struct bt_simple_mouse_cb sm_cbs = {
 	.move_xy = sm_move_xy_cb,
+	.velocity_xy = sm_velocity_xy_cb,
 	.buttons = sm_buttons_cb,
 };
 
@@ -110,12 +154,16 @@ static void connected(struct bt_conn *conn, uint8_t err)
 		printk("Connection failed (err 0x%02x)\n", err);
 	} else {
 		printk("Connected\n");
+		_dx = 0;
+		_dy = 0;
+		k_timer_start(&velocity_timer, K_MSEC(8), K_MSEC(8));
 	}
 }
 
 static void disconnected(struct bt_conn *conn, uint8_t reason)
 {
 	printk("Disconnected (reason 0x%02x)\n", reason);
+	k_timer_stop(&velocity_timer);
 }
 
 BT_CONN_CB_DEFINE(conn_callbacks) = {

src/simplems.c

@@ -1,28 +1,32 @@
-#include <zephyr/types.h>
 #include <stddef.h>
 #include <string.h>
 #include <errno.h>
-#include <zephyr.h>
-#include <init.h>
+#include <zephyr/kernel.h>
+#include <zephyr/init.h>
+#include <zephyr/types.h>
 
-#include <bluetooth/bluetooth.h>
-#include <bluetooth/hci.h>
-#include <bluetooth/conn.h>
-#include <bluetooth/uuid.h>
-#include <bluetooth/gatt.h>
+#include <zephyr/bluetooth/bluetooth.h>
+#include <zephyr/bluetooth/hci.h>
+#include <zephyr/bluetooth/conn.h>
+#include <zephyr/bluetooth/uuid.h>
+#include <zephyr/bluetooth/gatt.h>
 
 #include "simplems.h"
 
 static struct bt_uuid_128 simplems_uuid = BT_UUID_INIT_128(
 	BT_UUID_SIMPLE_MOUSE_SERVICE);
 
 // 0x56beb2d8, 0x64eb, 0x4e33, 0x96d4, 0xe3f394041d0b  (svc)
-// 0x83986548, 0x8703, 0x4272, 0xa124, 0x84abb9d03217  (xy)
+// 0x83986548, 0x8703, 0x4272, 0xa124, 0x84abb9d03217  (move xy)
+// 0x3cabb56e, 0x27a7, 0x45fa, 0x996a, 0x582f581d6aa3  (velocity xy)
 // 0x5062c9c1, 0xca09, 0x47f9, 0x84f6, 0x725ef8091bf9  (btn)
 
 static const struct bt_uuid_128 simplems_move_xy_uuid = BT_UUID_INIT_128(
 	BT_UUID_128_ENCODE(0x83986548, 0x8703, 0x4272, 0xa124, 0x84abb9d03217));
 
+static const struct bt_uuid_128 simplems_velocity_xy_uuid = BT_UUID_INIT_128(
+	BT_UUID_128_ENCODE(0x3cabb56e, 0x27a7, 0x45fa, 0x996a, 0x582f581d6aa3));
+
 static const struct bt_uuid_128 simplems_buttons_uuid = BT_UUID_INIT_128(
 	BT_UUID_128_ENCODE(0x5062c9c1, 0xca09, 0x47f9, 0x84f6, 0x725ef8091bf9));
 
@@ -56,6 +60,28 @@ static ssize_t write_move_xy(struct bt_conn *conn,
     return len;
 }
 
+static ssize_t write_velocity_xy(struct bt_conn *conn,
+			      const struct bt_gatt_attr *attr,
+			      const void *buf, uint16_t len,
+			      uint16_t offset, uint8_t flags)
+{
+	int16_t val[2];
+
+	if (offset != 0) {
+		return BT_GATT_ERR(BT_ATT_ERR_INVALID_OFFSET);
+	} else if (len != sizeof(val)) {
+		return BT_GATT_ERR(BT_ATT_ERR_INVALID_ATTRIBUTE_LEN);
+	}
+
+	(void)memcpy(&val, buf, len);
+
+    if (sm_cbs->velocity_xy) {
+        sm_cbs->velocity_xy(val[0], val[1]);
+    }
+
+    return len;
+}
+
 static ssize_t write_buttons(struct bt_conn *conn,
 			      const struct bt_gatt_attr *attr,
 			      const void *buf, uint16_t len,
@@ -85,6 +111,10 @@ BT_GATT_SERVICE_DEFINE(sm_svc,
                 BT_GATT_PERM_WRITE,
                 NULL, write_move_xy, NULL),
     BT_GATT_CUD("Move XY", BT_GATT_PERM_READ),
+    BT_GATT_CHARACTERISTIC(&simplems_velocity_xy_uuid.uuid, BT_GATT_CHRC_WRITE,
+                BT_GATT_PERM_WRITE,
+                NULL, write_velocity_xy, NULL),
+    BT_GATT_CUD("Velocity XY", BT_GATT_PERM_READ),
     BT_GATT_CHARACTERISTIC(&simplems_buttons_uuid.uuid, BT_GATT_CHRC_WRITE,
                 BT_GATT_PERM_WRITE,
                 NULL, write_buttons, NULL),

src/simplems.h

@@ -9,17 +9,20 @@ extern "C" {
 
 // 56beb2d8-64eb-4e33-96d4-e3f394041d0b (service)
 // 83986548-8703-4272-a124-84abb9d03217 (move x & y)
+// 3cabb56e-27a7-45fa-996a-582f581d6aa3 (velocity x & y)
 // 5062c9c1-ca09-47f9-84f6-725ef8091bf9 (buttons)
 
 #define BT_UUID_SIMPLE_MOUSE_SERVICE \
 	BT_UUID_128_ENCODE(0x56beb2d8, 0x64eb, 0x4e33, 0x96d4, 0xe3f394041d0b)
 
 typedef void (*simple_mouse_move_xy_cb)(int8_t distx, int8_t disty);
+typedef void (*simple_mouse_velocity_xy_cb)(int16_t vx, int16_t vy);
 typedef void (*simple_mouse_buttons_cb)(uint8_t buttons);
 
 struct bt_simple_mouse_cb {
-    simple_mouse_move_xy_cb move_xy;
-    simple_mouse_buttons_cb buttons;
+    simple_mouse_move_xy_cb     move_xy;
+    simple_mouse_velocity_xy_cb velocity_xy;
+    simple_mouse_buttons_cb     buttons;
 };
 
 void bt_simple_mouse_register_cb(struct bt_simple_mouse_cb *cb);

web/main-app.js

@@ -2,6 +2,8 @@
 import { MultiJoystick } from './multi-joystick.js';
 import { SimpleDriver } from './simple-driver.js';
 
+const _use_velocity = false;
+
 const template = document.createElement('template');
 template.innerHTML = `
 <style>
@@ -168,14 +170,26 @@ export class MainApp extends HTMLElement {
         this.#initButtonHandlers();
 
         this.#joystick = this.shadowRoot.querySelector('multi-joystick');
-        this.#joystick.addEventListener('move', e => this.#lastpos = e.detail.pos);
+
+        if (_use_velocity) {
+            this.#joystick.addEventListener('move', e => {
+                this.#lastpos = e.detail.pos;
+                if (this.#lastpos) {
+                    SimpleDriver.velocity(this.#lastpos.x*2000, this.#lastpos.y*2000);
+                } else {
+                    SimpleDriver.velocity(0, 0);
+                }
+            });
+        } else {
+            this.#joystick.addEventListener('move', e => this.#lastpos = e.detail.pos);
+            setInterval(this.doMove, 100);
+        }
 
         this.#connectbtn.addEventListener('click', this.toggleConnection);
 
         SimpleDriver.addEventListener('connect', this.handleConnect);
         SimpleDriver.addEventListener('disconnect', this.handleDisconnect);
 
-        setInterval(this.doMove, 100);
     }
 
     // TODO: Cleanup

web/simple-driver.js

@@ -8,6 +8,7 @@
 
 const SimpleMouseLinkUUID = '56beb2d8-64eb-4e33-96d4-e3f394041d0b';
 const SimpleMouseMoveXYUUID = '83986548-8703-4272-a124-84abb9d03217';
+const SimpleMouseVelocityXYUUID = '3cabb56e-27a7-45fa-996a-582f581d6aa3';
 const SimpleMouseButtonsUUID = '5062c9c1-ca09-47f9-84f6-725ef8091bf9';
 
 const cap_val = (val) => {
@@ -31,7 +32,16 @@ export const SimpleDriver = new class extends EventTarget {
             const xx = cap_val(x);
             const yy = cap_val(y);
             console.log("Mouse move:", xx, yy)
-            if (xx || yy) this.#writeFuncs.move_xy.writeValue(new Uint8Array([xx, yy]));
+            if (xx || yy) this.#writeFuncs.move_xy.writeValue(new Int8Array([xx, yy]));
+        }
+    }
+
+    velocity(x, y) {
+        if (this.#writeFuncs.velocity_xy) {
+            const xx = Math.round(x);
+            const yy = Math.round(y);
+            console.log("Mouse velocity:", xx, yy)
+            this.#writeFuncs.velocity_xy.writeValue(new Int16Array([xx, yy]));
         }
     }
 
@@ -46,6 +56,7 @@ export const SimpleDriver = new class extends EventTarget {
     async fetchWriteCharacteristics(server) {
         const service = await server.getPrimaryService(SimpleMouseLinkUUID);
         this.#writeFuncs.move_xy = await service.getCharacteristic(SimpleMouseMoveXYUUID);
+        this.#writeFuncs.velocity_xy = await service.getCharacteristic(SimpleMouseVelocityXYUUID);
         this.#writeFuncs.buttons = await service.getCharacteristic(SimpleMouseButtonsUUID);
     }