Simple rumble API for haptic

Edgar Simo      2011-02-20 10:27:52 PST

Adding patch that adds a simplified API for the haptic subsystem built ontop of
the "real one" for those who want simple rumble without jumping through hoops.

Adds 4 functions:

- extern DECLSPEC int SDLCALL SDL_HapticRumbleSupported(SDL_Haptic * haptic);
- extern DECLSPEC int SDLCALL SDL_HapticRumbleInit(SDL_Haptic * haptic);
- extern DECLSPEC int SDLCALL SDL_HapticRumblePlay(SDL_Haptic * haptic, float
strength, Uint32 length );
- extern DECLSPEC int SDLCALL SDL_HapticRumbleStop(SDL_Haptic * haptic);

Also provided is test/testrumble.c which does test this.

This has all been tested on linux and has worked, but due to being built ontop
of the other haptic API it should work on all OS the same.

src/haptic/SDL_haptic.c

@@ -143,6 +143,7 @@ SDL_HapticOpen(int device_index)
 
     /* Initialize the haptic device */
     SDL_memset(haptic, 0, (sizeof *haptic));
+    haptic->rumble_id = -1;
     haptic->index = device_index;
     if (SDL_SYS_HapticOpen(haptic) < 0) {
         SDL_free(haptic);
@@ -292,6 +293,7 @@ SDL_HapticOpenFromJoystick(SDL_Joystick * joystick)
 
     /* Initialize the haptic device */
     SDL_memset(haptic, 0, sizeof(SDL_Haptic));
+    haptic->rumble_id = -1;
     if (SDL_SYS_HapticOpenFromJoystick(haptic, joystick) < 0) {
         SDL_free(haptic);
         return NULL;
@@ -706,3 +708,110 @@ SDL_HapticStopAll(SDL_Haptic * haptic)
 
     return SDL_SYS_HapticStopAll(haptic);
 }
+
+static int
+SDL_HapticRumbleCreate(SDL_HapticEffect * efx)
+{
+   SDL_memset(efx, 0, sizeof(SDL_HapticEffect));
+   efx->type = SDL_HAPTIC_SINE;
+   efx->periodic.period = 1000;
+   efx->periodic.magnitude = 0x4000;
+   efx->periodic.length = 5000;
+   efx->periodic.attack_length = 0;
+   efx->periodic.fade_length = 0;
+}
+
+/*
+ * Checks to see if rumble is supported.
+ */
+int
+SDL_HapticRumbleSupported(SDL_Haptic * haptic)
+{
+    SDL_HapticEffect efx;
+
+    if (!ValidHaptic(haptic)) {
+        return -1;
+    }
+
+    SDL_HapticRumbleCreate(&efx);
+    return SDL_HapticEffectSupported(haptic, &efx);
+}
+
+/*
+ * Initializes the haptic device for simple rumble playback.
+ */
+int
+SDL_HapticRumbleInit(SDL_Haptic * haptic)
+{
+    if (!ValidHaptic(haptic)) {
+        return -1;
+    }
+
+    /* Already allocated. */
+    if (haptic->rumble_id >= 0) {
+        return 0;
+    }
+
+    /* Copy over. */
+    SDL_HapticRumbleCreate(&haptic->rumble_effect);
+    haptic->rumble_id = SDL_HapticNewEffect(haptic, &haptic->rumble_effect);
+    if (haptic->rumble_id >= 0) {
+        return 0;
+    }
+    return -1;
+}
+
+/*
+ * Runs simple rumble on a haptic device
+ */
+int
+SDL_HapticRumblePlay(SDL_Haptic * haptic, float strength, Uint32 length)
+{
+    int ret;
+    SDL_HapticPeriodic *efx;
+
+    if (!ValidHaptic(haptic)) {
+        return -1;
+    }
+
+    if (haptic->rumble_id < 0) {
+        SDL_SetError("Haptic: Rumble effect not initialized on haptic device");
+        return -1;
+    }
+
+    /* Clamp strength. */
+    if (strength > 1.0f) {
+        strength = 1.0f;
+    }
+    else if (strength < 0.0f) {
+        strength = 0.0f;
+    }
+
+    /* New effect. */
+    efx = &haptic->rumble_effect.periodic;
+    efx->magnitude = (Sint16)(32767.0f*strength);
+    efx->length = length;
+    ret = SDL_HapticUpdateEffect(haptic, haptic->rumble_id, &haptic->rumble_effect);
+
+    return SDL_HapticRunEffect(haptic, haptic->rumble_id, 1);
+}
+
+/*
+ * Stops the simple rumble on a haptic device.
+ */
+int
+SDL_HapticRumbleStop(SDL_Haptic * haptic)
+{
+    if (!ValidHaptic(haptic)) {
+        return -1;
+    }
+
+    if (haptic->rumble_id < 0) {
+        SDL_SetError("Haptic: Rumble effect not initialized on haptic device");
+        return -1;
+    }
+
+    return SDL_HapticStopEffect(haptic, haptic->rumble_id);
+}
+
+

src/haptic/SDL_syshaptic.h

@@ -52,6 +52,9 @@ struct _SDL_Haptic
 
     struct haptic_hwdata *hwdata;       /* Driver dependent */
     int ref_count;              /* Count for multiple opens */
+
+    int rumble_id;              /* ID of rumble effect for simple rumble API. */
+    SDL_HapticEffect rumble_effect; /* Rumble effect. */
 };
 
 /*