Add support for multiple pointer acceleration schemes. #8583

Available acceleration schemes:
 - xorg classic scheme.
 - the new "Predictable" polynomial accel scheme.

X.Org Bug 8583 <http://bugs.freedesktop.org/show_bug.cgi?id=8583>

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

4 files changed, 123 insertions, 2 deletions

diff --git a/include/Makefile.am b/include/Makefile.am
index 5edefe7b5..3d7879933 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -35,6 +35,7 @@ sdk_HEADERS =		\
 	privates.h	\
 	property.h	\
 	propertyst.h	\
+	ptrveloc.h  \
 	region.h	\
 	regionstr.h	\
 	registry.h	\
diff --git a/include/input.h b/include/input.h
index 59f4e7f95..ba4492839 100644
--- a/include/input.h
+++ b/include/input.h
@@ -63,6 +63,12 @@ SOFTWARE.
 #define POINTER_ABSOLUTE (1 << 2)
 #define POINTER_ACCELERATE (1 << 3)
 
+/*int constants for pointer acceleration schemes*/
+#define PtrAccelNoOp            0
+#define PtrAccelPredictable     1
+#define PtrAccelClassic         2
+#define PtrAccelDefault         PtrAccelPredictable
+
 #define MAX_VALUATORS 36 /* XXX from comment in dix/getevents.c */
 
 #define NO_AXIS_LIMITS -1
@@ -155,6 +161,17 @@ typedef void (*DeviceUnwrapProc)(
     void* /*data*/
     );
 
+/* pointer acceleration handling */
+typedef void (*PointerAccelSchemeProc)(
+    DeviceIntPtr /*pDev*/,
+    int /*first_valuator*/,
+    int /*num_valuators*/,
+    int* /*valuators*/,
+    int /*evtime*/);
+
+typedef void (*DeviceCallbackProc)(
+              DeviceIntPtr /*pDev*/);
+
 typedef struct _DeviceRec {
     pointer	devicePrivate;
     ProcessInputProc processInputProc;	/* current */
@@ -280,6 +297,10 @@ extern Bool InitValuatorClassDeviceStruct(
     int /*numMotionEvents*/,
     int /*mode*/);
 
+extern Bool InitPointerAccelerationScheme(
+    DeviceIntPtr /*dev*/,
+    int /*scheme*/);
+
 extern Bool InitAbsoluteClassDeviceStruct(
     DeviceIntPtr /*device*/);
 
diff --git a/include/inputstr.h b/include/inputstr.h
index f3211a972..3f5c76870 100644
--- a/include/inputstr.h
+++ b/include/inputstr.h
@@ -166,6 +166,13 @@ typedef struct _AxisInfo {
     int		max_value;
 } AxisInfo, *AxisInfoPtr;
 
+typedef struct _ValuatorAccelerationRec {
+    int                         number;
+    PointerAccelSchemeProc      AccelSchemeProc;
+    void                       *accelData; /* at disposal of AccelScheme */
+    DeviceCallbackProc          AccelCleanupProc;
+} ValuatorAccelerationRec, *ValuatorAccelerationPtr;
+
 typedef struct _ValuatorClassRec {
     int		 	  numMotionEvents;
     int                   first_motion;
@@ -177,8 +184,8 @@ typedef struct _ValuatorClassRec {
     AxisInfoPtr 	  axes;
     unsigned short	  numAxes;
     int			  *axisVal; /* always absolute, but device-coord system */
-    float                 dxremaind, dyremaind; /* for acceleration */
     CARD8	 	  mode;
+    ValuatorAccelerationRec	accelScheme;
 } ValuatorClassRec, *ValuatorClassPtr;
 
 typedef struct _ButtonClassRec {
@@ -467,9 +474,12 @@ typedef struct _DeviceIntRec {
     /* last valuator values recorded, not posted to client;
      * for slave devices, valuators is in device coordinates
      * for master devices, valuators is in screen coordinates
-     * see dix/getevents.c */
+     * see dix/getevents.c
+     * remainder supports acceleration
+     */
     struct {
         int             valuators[MAX_VALUATORS];
+        float           remainder[MAX_VALUATORS];
         int             numValuators;
     } last;
 
diff --git a/include/ptrveloc.h b/include/ptrveloc.h
new file mode 100644
index 000000000..dd5ee5067
--- /dev/null
+++ b/include/ptrveloc.h
@@ -0,0 +1,89 @@
+/*
+*  2006-2008 by Simon Thum
+*/
+
+#ifndef POINTERVELOCITY_H
+#define POINTERVELOCITY_H
+
+#include <input.h> /* DeviceIntPtr */
+
+#define MAX_VELOCITY_FILTERS 8
+
+struct _DeviceVelocityRec;
+
+/**
+ * profile
+ * returns actual acceleration depending on velocity, acceleration control,...
+ */
+typedef float (*PointerAccelerationProfileFunc)
+              (struct _DeviceVelocityRec* /*pVel*/,
+               float /*threshold*/, float /*acc*/);
+
+/**
+ * a filter stage contains the data for the adaptive IIR filtering.
+ * To improve results, one may run several parallel filters
+ * which have different decays. Since more integration means more
+ * delay, a given filter only does good matches in a specific phase of
+ * a stroke.
+ *
+ * Basically, the coupling feature makes one filter fairly enough,
+ * so that is the default.
+ */
+typedef struct _FilterStage {
+    float*  fading_lut;     /* lookup for adaptive IIR filter */
+    int     fading_lut_size; /* size of lookup table */
+    float   rdecay;     /* reciprocal weighting halflife in ms */
+    float   current;
+} FilterStage, *FilterStagePtr;
+
+/**
+ * Contains all data needed to implement mouse ballistics
+ */
+typedef struct _DeviceVelocityRec {
+    FilterStage filters[MAX_VELOCITY_FILTERS];
+    float   velocity;       /* velocity as guessed by algorithm */
+    int     lrm_time;       /* time the last motion event was processed  */
+    int     last_dx, last_dy; /* last motion delta */
+    int     last_diff;      /* last time-diff */
+    float   corr_mul;       /* config: multiply this into velocity */
+    float   const_acceleration;  /* config: (recipr.) const deceleration */
+    float   min_acceleration;    /* config: minimum acceleration */
+    short   reset_time;     /* config: reset non-visible state after # ms */
+    short   use_softening;  /* config: use softening of mouse values */
+    float   coupling;       /* config: max. divergence before coupling */
+    PointerAccelerationProfileFunc Profile;
+    PointerAccelerationProfileFunc deviceSpecificProfile;
+    void*   profile_private;/* extended data, see  SetAccelerationProfile() */
+    struct {   /* to be able to query this information */
+        int     profile_number;
+        int     filter_usecount[MAX_VELOCITY_FILTERS];
+    } statistics;
+} DeviceVelocityRec, *DeviceVelocityPtr;
+
+
+extern void
+InitVelocityData(DeviceVelocityPtr s);
+
+extern void
+InitFilterChain(DeviceVelocityPtr s, float rdecay, float degression,
+                int lutsize, int stages);
+
+extern int
+SetAccelerationProfile(DeviceVelocityPtr s, int profile_num);
+
+extern void
+SetDeviceSpecificAccelerationProfile(DeviceIntPtr s,
+                                     PointerAccelerationProfileFunc profile);
+
+extern void
+AccelerationDefaultCleanup(DeviceIntPtr pDev);
+
+extern void
+acceleratePointerPredictable(DeviceIntPtr pDev, int first_valuator,
+                             int num_valuators, int *valuators, int evtime);
+
+extern void
+acceleratePointerClassic(DeviceIntPtr pDev, int first_valuator,
+                         int num_valuators, int *valuators, int ignore);
+
+#endif  /* POINTERVELOCITY_H */