Fixed issue where the throttle and other axes on racing wheels don't …

…start at zero and show up as immediate input when the wheel is turned for the first time. Wait until they are actually moved before generating input from them.
libsdl-org · Dec 23, 2016 · ca019da · ca019da
1 parent b2f6c4c
commit ca019da
Show file tree

Hide file tree

Showing 3 changed files with 35 additions and 35 deletions.
diff --git a/src/joystick/SDL_gamecontroller.c b/src/joystick/SDL_gamecontroller.c
@@ -1132,12 +1132,12 @@ SDL_GameControllerOpen(int device_index)
         int leftTriggerMapping = gamecontroller->mapping.axes[SDL_CONTROLLER_AXIS_TRIGGERLEFT];
         int rightTriggerMapping = gamecontroller->mapping.axes[SDL_CONTROLLER_AXIS_TRIGGERRIGHT];
         if (leftTriggerMapping >= 0) {
-            gamecontroller->joystick->axes[leftTriggerMapping] =
-            gamecontroller->joystick->axes_zero[leftTriggerMapping] = (Sint16)-32768;
+            gamecontroller->joystick->axes[leftTriggerMapping].value =
+            gamecontroller->joystick->axes[leftTriggerMapping].zero = (Sint16)-32768;
         }
         if (rightTriggerMapping >= 0) {
-            gamecontroller->joystick->axes[rightTriggerMapping] =
-            gamecontroller->joystick->axes_zero[rightTriggerMapping] = (Sint16)-32768;
+            gamecontroller->joystick->axes[rightTriggerMapping].value =
+            gamecontroller->joystick->axes[rightTriggerMapping].zero = (Sint16)-32768;
         }
     }
 

diff --git a/src/joystick/SDL_joystick.c b/src/joystick/SDL_joystick.c
@@ -170,20 +170,16 @@ SDL_JoystickOpen(int device_index)
         joystick->name = NULL;
 
     if (joystick->naxes > 0) {
-        joystick->axes = (Sint16 *) SDL_malloc(joystick->naxes * sizeof(Sint16));
-        joystick->axes_zero = (Sint16 *) SDL_malloc(joystick->naxes * sizeof(Sint16));
+        joystick->axes = (SDL_JoystickAxisInfo *) SDL_calloc(joystick->naxes, sizeof(SDL_JoystickAxisInfo));
     }
     if (joystick->nhats > 0) {
-        joystick->hats = (Uint8 *) SDL_malloc
-            (joystick->nhats * sizeof(Uint8));
+        joystick->hats = (Uint8 *) SDL_calloc(joystick->nhats, sizeof(Uint8));
     }
     if (joystick->nballs > 0) {
-        joystick->balls = (struct balldelta *) SDL_malloc
-            (joystick->nballs * sizeof(*joystick->balls));
+        joystick->balls = (struct balldelta *) SDL_calloc(joystick->nballs, sizeof(*joystick->balls));
     }
     if (joystick->nbuttons > 0) {
-        joystick->buttons = (Uint8 *) SDL_malloc
-            (joystick->nbuttons * sizeof(Uint8));
+        joystick->buttons = (Uint8 *) SDL_calloc(joystick->nbuttons, sizeof(Uint8));
     }
     if (((joystick->naxes > 0) && !joystick->axes)
         || ((joystick->nhats > 0) && !joystick->hats)
@@ -194,20 +190,6 @@ SDL_JoystickOpen(int device_index)
         SDL_UnlockJoystickList();
         return NULL;
     }
-    if (joystick->axes) {
-        SDL_memset(joystick->axes, 0, joystick->naxes * sizeof(Sint16));
-        SDL_memset(joystick->axes_zero, 0, joystick->naxes * sizeof(Sint16));
-    }
-    if (joystick->hats) {
-        SDL_memset(joystick->hats, 0, joystick->nhats * sizeof(Uint8));
-    }
-    if (joystick->balls) {
-        SDL_memset(joystick->balls, 0,
-            joystick->nballs * sizeof(*joystick->balls));
-    }
-    if (joystick->buttons) {
-        SDL_memset(joystick->buttons, 0, joystick->nbuttons * sizeof(Uint8));
-    }
     joystick->epowerlevel = SDL_JOYSTICK_POWER_UNKNOWN;
 
     /* Add joystick to list */
@@ -302,7 +284,7 @@ SDL_JoystickGetAxis(SDL_Joystick * joystick, int axis)
         return (0);
     }
     if (axis < joystick->naxes) {
-        state = joystick->axes[axis];
+        state = joystick->axes[axis].value;
     } else {
         SDL_SetError("Joystick only has %d axes", joystick->naxes);
         state = 0;
@@ -486,7 +468,6 @@ SDL_JoystickClose(SDL_Joystick * joystick)
 
     /* Free the data associated with this joystick */
     SDL_free(joystick->axes);
-    SDL_free(joystick->axes_zero);
     SDL_free(joystick->hats);
     SDL_free(joystick->balls);
     SDL_free(joystick->buttons);
@@ -621,22 +602,34 @@ SDL_PrivateJoystickAxis(SDL_Joystick * joystick, Uint8 axis, Sint16 value)
     if (axis >= joystick->naxes) {
         return 0;
     }
-    if (value == joystick->axes[axis]) {
+    if (value == joystick->axes[axis].value) {
         return 0;
     }
+    if (!joystick->axes[axis].moved) {
+        if (joystick->axes[axis].intial_value == 0) {
+            joystick->axes[axis].intial_value = value;
+            return 0;
+        }
+        if (value == joystick->axes[axis].intial_value) {
+            return 0;
+        }
+
+        /* We got more than 0 and the initial value from the joystick, consider it as having actually moved */
+        joystick->axes[axis].moved = SDL_TRUE;
+    }
 
     /* We ignore events if we don't have keyboard focus, except for centering
      * events.
      */
     if (SDL_PrivateJoystickShouldIgnoreEvent()) {
-        if ((value > joystick->axes_zero[axis] && value >= joystick->axes[axis]) ||
-            (value < joystick->axes_zero[axis] && value <= joystick->axes[axis])) {
+        if ((value > joystick->axes[axis].zero && value >= joystick->axes[axis].value) ||
+            (value < joystick->axes[axis].zero && value <= joystick->axes[axis].value)) {
             return 0;
         }
     }
 
     /* Update internal joystick state */
-    joystick->axes[axis] = value;
+    joystick->axes[axis].value = value;
 
     /* Post the event, if desired */
     posted = 0;
@@ -807,7 +800,7 @@ SDL_JoystickUpdate(void)
 
             /* Tell the app that everything is centered/unpressed...  */
             for (i = 0; i < joystick->naxes; i++) {
-                SDL_PrivateJoystickAxis(joystick, i, joystick->axes_zero[i]);
+                SDL_PrivateJoystickAxis(joystick, i, joystick->axes[i].zero);
             }
 
             for (i = 0; i < joystick->nbuttons; i++) {

diff --git a/src/joystick/SDL_sysjoystick.h b/src/joystick/SDL_sysjoystick.h
@@ -29,14 +29,21 @@
 #include "SDL_joystick_c.h"
 
 /* The SDL joystick structure */
+typedef struct _SDL_JoystickAxisInfo
+{
+    Sint16 value;           /* Current axis states */
+    Sint16 zero;            /* Zero point on the axis (-32768 for triggers) */
+    Sint16 intial_value;    /* The very first value we saw on this axis */
+    SDL_bool moved;         /* Whether the axis has moved */
+} SDL_JoystickAxisInfo;
+
 struct _SDL_Joystick
 {
     SDL_JoystickID instance_id; /* Device instance, monotonically increasing from 0 */
     char *name;                 /* Joystick name - system dependent */
 
     int naxes;                  /* Number of axis controls on the joystick */
-    Sint16 *axes;               /* Current axis states */
-    Sint16 *axes_zero;          /* Zero point on the axis (-32768 for triggers) */
+    SDL_JoystickAxisInfo *axes;
 
     int nhats;                  /* Number of hats on the joystick */
     Uint8 *hats;                /* Current hat states */