[PATCH evdev 5/5] Keep the states of multitouch events

[Benjamin Tissoires]

The idea here is to track the different touches given by the device.

Currently, the driver continue to send the trackingID as the XInput
implementation in the server does not contains the masks of the
valuators.

Note that I currently assume two things:
- the trackingID has to be given by the device
- the device reports all multitouch fields at each frame

Signed-off-by: Benjamin Tissoires <tissoire at cena.fr>
---
 src/evdev.c |   73 ++++++++++++++++++++++++++++++++++++++++++++++++++++------
 src/evdev.h |   11 +++++++++
 2 files changed, 76 insertions(+), 8 deletions(-)

diff --git a/src/evdev.c b/src/evdev.c
index 76af8dc..554e796 100644
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -556,12 +556,10 @@ EvdevProcessAbsoluteMotionEvent(InputInfoPtr pInfo, struct input_event *ev)
 
     if (ev->code < ABS_MT_TOUCH_MAJOR)
         pEvdev->vals[pEvdev->axis_map[ev->code]] = value;
-    else if (pEvdev->current_num_multitouch < EVDEV_MAX_TOUCHPOINTS) {
-        /* MT value -> store it at the first available place */
-        pEvdev->vals[pEvdev->axis_map[ev->code] +
-                        pEvdev->current_num_multitouch * pEvdev->mt_num_valuators] = value;
-    } else
-        return; /* mt-event, but not enough place to store it */
+    else
+        /* multitouch event */
+        pEvdev->mt_current_vals[pEvdev->axis_map[ev->code] -
+                pEvdev->mt_first_axis] = value;
 
     if (ev->code == ABS_X)
         pEvdev->abs |= ABS_X_VALUE;
@@ -692,6 +690,7 @@ EvdevProcessSyncEvent(InputInfoPtr pInfo, struct input_event *ev)
     int num_v = 0, first_v = 0;
     int v[MAX_VALUATORS];
     EvdevPtr pEvdev = pInfo->private;
+    int i;
 
     EvdevProcessValuators(pInfo, v, &num_v, &first_v);
 
@@ -704,7 +703,17 @@ EvdevProcessSyncEvent(InputInfoPtr pInfo, struct input_event *ev)
     pEvdev->num_queue = 0;
     pEvdev->abs = 0;
     pEvdev->rel = 0;
-    pEvdev->current_num_multitouch = 0;
+
+    if (pEvdev->flags & EVDEV_MULTITOUCH) {
+        pEvdev->current_num_multitouch = 0;
+
+        /* clean up known multitouch */
+        for (i = 0; i < EVDEV_MAX_TOUCHPOINTS; i++) {
+            if (!pEvdev->known_touches[i].used)
+                pEvdev->known_touches[i].id = -1;
+            pEvdev->known_touches[i].used = FALSE;
+        }
+    }
 }
 
 /**
@@ -714,7 +723,48 @@ static void
 EvdevProcessMTSyncReport(InputInfoPtr pInfo, struct input_event *ev)
 {
     EvdevPtr pEvdev = pInfo->private;
-    pEvdev->current_num_multitouch++;
+    EvdevTouchPtr pTouch = NULL;
+
+    /* find the previously associated MT */
+    if (pEvdev->axis_map[ABS_MT_TRACKING_ID] > -1) {
+        /* the tracking ID is given by the device */
+        int i;
+        int id = pEvdev->mt_current_vals[
+            pEvdev->axis_map[ABS_MT_TRACKING_ID] - pEvdev->mt_first_axis];
+
+        /* Get a TouchDataRec to keep the state of the MT-event */
+        /* first, find if the id was previously assigned */
+        for (i = 0; i < EVDEV_MAX_TOUCHPOINTS; i++) {
+            if (pEvdev->known_touches[i].id == id) {
+                pTouch = &pEvdev->known_touches[i];
+                break;
+            }
+        }
+
+        if (!pTouch) {
+            /* the TouchDataRec was not found, look at an unassigned one */
+            for (i = 0; i < EVDEV_MAX_TOUCHPOINTS; i++) {
+                if (pEvdev->known_touches[i].id <= 0) {
+                    pTouch = &pEvdev->known_touches[i];
+                    pTouch->id = id;
+                    break;
+                }
+            }
+        }
+
+        if (pTouch) {
+            pTouch->used = TRUE;
+            pTouch->position = pEvdev->current_num_multitouch; /* currently as mask for valuators is non available */
+        }
+    }
+
+    if (pTouch) {
+        memcpy(pEvdev->vals + pEvdev->mt_first_axis +
+                pTouch->position * pEvdev->mt_num_valuators,
+                pEvdev->mt_current_vals,
+                sizeof(int) * pEvdev->mt_num_valuators);
+        pEvdev->current_num_multitouch++;
+    }
 }
 
 /**
@@ -2091,6 +2141,7 @@ EvdevPreInit(InputDriverPtr drv, IDevPtr dev, int flags)
     const char *device, *str;
     int num_calibration = 0, calibration[4] = { 0, 0, 0, 0 };
     EvdevPtr pEvdev;
+    int i;
 
     if (!(pInfo = xf86AllocateInput(drv, 0)))
 	return NULL;
@@ -2188,6 +2239,12 @@ EvdevPreInit(InputDriverPtr drv, IDevPtr dev, int flags)
         return NULL;
     }
 
+    /* mt-related */
+    for (i = 0; i < EVDEV_MAX_TOUCHPOINTS; i++) {
+        pEvdev->known_touches[i].id = 0;
+        pEvdev->known_touches[i].used = FALSE;
+    }
+
     EvdevAddDevice(pInfo);
 
     if (pEvdev->flags & EVDEV_BUTTON_EVENTS)
diff --git a/src/evdev.h b/src/evdev.h
index 0dba366..9b5c1cd 100644
--- a/src/evdev.h
+++ b/src/evdev.h
@@ -116,6 +116,13 @@ typedef struct {
     int val;		/* State of the key/button; pressed or released. */
 } EventQueueRec, *EventQueuePtr;
 
+/* Touch record to store if a touch was presviously reported */
+typedef struct {
+    int id; /* the tracking ID of the touch (>0 means touch alive) */
+    BOOL used; /* true if seen in the current frame (between two SYNC_EVENT) */
+    int position; /* the position in the collection of touches */
+} EvdevTouchRec, *EvdevTouchPtr;
+
 typedef struct {
     const char *device;
     int grabDevice;         /* grab the event device? */
@@ -199,6 +206,10 @@ typedef struct {
     unsigned int mt_first_axis;
     unsigned int mt_num_valuators;
     unsigned int current_num_multitouch;
+
+    /* a list of the current touches */
+    EvdevTouchRec known_touches[EVDEV_MAX_TOUCHPOINTS];
+    int mt_current_vals[ABS_CNT - ABS_MT_TOUCH_MAJOR];
 } EvdevRec, *EvdevPtr;
 
 /* Event posting functions */
-- 
1.6.6.1