Pointer confinement support (opt-in) (#17169)

New environment set call to enable a bit more sensible handling of
absolute pointing devices (pointer and lightgun). With the
confinement enabled, pointing devices will not return neither
-0x8000 nor (0,0), which was anyway dependent on the input driver,
instead they will stay at the extreme edge.

cores/libretro-net-retropad/net_retropad_core.c

@@ -785,6 +785,7 @@ void NETRETROPAD_CORE_PREFIX(retro_set_environment)(retro_environment_t cb)
       { "net_retropad_screen", "Start screen; Retropad|Keyboard tester|Sensor tester" },
       { "net_retropad_hide_analog_mismatch", "Hide mismatching analog button inputs; True|False" },
       { "net_retropad_pointer_test", "Pointer test; Off|Mouse|Pointer|Lightgun|Old lightgun" },
+      { "net_retropad_pointer_confine", "Pointer confinement; Off|Edge" },
       { NULL, NULL },
    };
    enum retro_pixel_format fmt = RETRO_PIXEL_FORMAT_RGB565;
@@ -806,15 +807,17 @@ void NETRETROPAD_CORE_PREFIX(retro_set_environment)(retro_environment_t cb)
 
 static void netretropad_check_variables(void)
 {
-   struct retro_variable var, var2, var3, var4, port_var, screen_var, hide_a_var, mouse_var;
+   unsigned pointer_confinement = RETRO_POINTER_CONFINEMENT_LEGACY;
-   var.key        = "net_retropad_ip_octet1";
+   struct retro_variable var, var2, var3, var4, port_var, screen_var, hide_a_var, mouse_var, confine_var;
-   var2.key       = "net_retropad_ip_octet2";
+   var.key         = "net_retropad_ip_octet1";
-   var3.key       = "net_retropad_ip_octet3";
+   var2.key        = "net_retropad_ip_octet2";
-   var4.key       = "net_retropad_ip_octet4";
+   var3.key        = "net_retropad_ip_octet3";
-   port_var.key   = "net_retropad_port";
+   var4.key        = "net_retropad_ip_octet4";
-   screen_var.key = "net_retropad_screen";
+   port_var.key    = "net_retropad_port";
-   hide_a_var.key = "net_retropad_hide_analog_mismatch";
+   screen_var.key  = "net_retropad_screen";
-   mouse_var.key  = "net_retropad_pointer_test";
+   hide_a_var.key  = "net_retropad_hide_analog_mismatch";
+   mouse_var.key   = "net_retropad_pointer_test";
+   confine_var.key = "net_retropad_pointer_confine";
 
    NETRETROPAD_CORE_PREFIX(environ_cb)(RETRO_ENVIRONMENT_GET_VARIABLE, &var);
    NETRETROPAD_CORE_PREFIX(environ_cb)(RETRO_ENVIRONMENT_GET_VARIABLE, &var2);
@@ -824,6 +827,7 @@ static void netretropad_check_variables(void)
    NETRETROPAD_CORE_PREFIX(environ_cb)(RETRO_ENVIRONMENT_GET_VARIABLE, &screen_var);
    NETRETROPAD_CORE_PREFIX(environ_cb)(RETRO_ENVIRONMENT_GET_VARIABLE, &hide_a_var);
    NETRETROPAD_CORE_PREFIX(environ_cb)(RETRO_ENVIRONMENT_GET_VARIABLE, &mouse_var);
+   NETRETROPAD_CORE_PREFIX(environ_cb)(RETRO_ENVIRONMENT_GET_VARIABLE, &confine_var);
 
    snprintf(server, sizeof(server), "%s.%s.%s.%s", var.value, var2.value, var3.value, var4.value);
    port = atoi(port_var.value);
@@ -849,6 +853,9 @@ static void netretropad_check_variables(void)
    else
       mouse_type = 0;
 
+   if (confine_var.value && strstr(confine_var.value,"Edge"))
+      pointer_confinement = RETRO_POINTER_CONFINEMENT_EDGE;
+   NETRETROPAD_CORE_PREFIX(environ_cb)(RETRO_ENVIRONMENT_SET_POINTER_CONFINEMENT, &pointer_confinement);
 }
 
 void NETRETROPAD_CORE_PREFIX(retro_set_audio_sample)(retro_audio_sample_t cb)

gfx/video_driver.c

@@ -694,14 +694,15 @@ bool video_driver_translate_coord_viewport(
       int16_t *res_x,        int16_t *res_y,
       int16_t *res_screen_x, int16_t *res_screen_y)
 {
-   int norm_vp_width         = (int)vp->width;
+   runloop_state_t *runloop_st = runloop_state_get_ptr();
-   int norm_vp_height        = (int)vp->height;
+   int norm_vp_width           = (int)vp->width;
-   int norm_full_vp_width    = (int)vp->full_width;
+   int norm_vp_height          = (int)vp->height;
-   int norm_full_vp_height   = (int)vp->full_height;
+   int norm_full_vp_width      = (int)vp->full_width;
-   int scaled_screen_x       = -0x8000; /* OOB */
+   int norm_full_vp_height     = (int)vp->full_height;
-   int scaled_screen_y       = -0x8000; /* OOB */
+   int scaled_screen_x         = -0x8000; /* Legacy OOB */
-   int scaled_x              = -0x8000; /* OOB */
+   int scaled_screen_y         = -0x8000; /* Legacy OOB */
-   int scaled_y              = -0x8000; /* OOB */
+   int scaled_x                = -0x8000; /* Legacy OOB */
+   int scaled_y                = -0x8000; /* Legacy OOB */
    if (   (norm_vp_width       <= 0)
        || (norm_vp_height      <= 0)
        || (norm_full_vp_width  <= 0)
@@ -722,12 +723,24 @@ bool video_driver_translate_coord_viewport(
    if (mouse_x >= 0 && mouse_x <= norm_vp_width)
       scaled_x        = ((2 * mouse_x * 0x7fff)
             / norm_vp_width) - 0x7fff;
-   else
+   else if (runloop_st->pointer_confinement == RETRO_POINTER_CONFINEMENT_EDGE)
-      scaled_x        = -0x8000; /* OOB */
+   {
+      if (mouse_x < 0)
+         scaled_x = -0x7fff;
+      else
+         scaled_x =  0x7fff;
+   }
 
    if (mouse_y >= 0 && mouse_y <= norm_vp_height)
       scaled_y        = ((2 * mouse_y * 0x7fff)
             / norm_vp_height) - 0x7fff;
+   else if (runloop_st->pointer_confinement == RETRO_POINTER_CONFINEMENT_EDGE)
+   {
+      if (mouse_y < 0)
+         scaled_y = -0x7fff;
+      else
+         scaled_y =  0x7fff;
+   }
 
    *res_x             = scaled_x;
    *res_y             = scaled_y;

libretro-common/include/libretro.h

@@ -432,6 +432,9 @@ extern "C" {
 #define RETRO_DEVICE_ID_POINTER_PRESSED   2
 #define RETRO_DEVICE_ID_POINTER_COUNT     3
 
+/* Values for pointer confinement */
+#define RETRO_POINTER_CONFINEMENT_LEGACY 0
+#define RETRO_POINTER_CONFINEMENT_EDGE   1
 /** @} */
 
 /* Returned from retro_get_region(). */
@@ -2569,6 +2572,31 @@ enum retro_mod
  */
 #define RETRO_ENVIRONMENT_GET_FILE_BROWSER_START_DIRECTORY 80
 
+/**
+ * Controls how the frontend should handle screen edges and off-screen for
+ * inputs returning screen coordinates (pointer and lightgun).
+ *
+ * Default behavior is that (0,0) coordinates are returned if cursor leaves
+ * the actual viewport, and resides on either the black padding area or
+ * outside the window (if there is one), but it is somewhat input driver
+ * dependent.
+ *
+ * Modified behavior is that coordinates will always be in the range of
+ * [-0x7fff,0x7fff], with the edge values meaning that cursor has left the
+ * viewport in that direction.
+ *
+ * @param[in] data <tt>const unsigned *</tt>.
+ * Pointer to a single \c unsigned that indicates the confinement method.
+ * Can point to a value of \c RETRO_POINTER_CONFINEMENT_LEGACY but this
+ * isn't necessary, pointer confinement support is opt-in.
+ * The behavior is not changed compared to the previous state if \c data
+ * is <tt>NULL</tt>.
+ * @returns \c true if the environment call is available.
+ * @see RETRO_DEVICE_POINTER
+ * @see RETRO_DEVICE_LIGHTGUN
+ */
+#define RETRO_ENVIRONMENT_SET_POINTER_CONFINEMENT 81
+
 /**@}*/
 
 /**

runloop.c

@@ -3586,6 +3586,13 @@ bool runloop_environment_cb(unsigned cmd, void *data)
             }
          }
          break;
+
+      case RETRO_ENVIRONMENT_SET_POINTER_CONFINEMENT:
+         if (data)
+            runloop_st->pointer_confinement = *(unsigned*)data;
+         RARCH_LOG("[Environ]: RETRO_ENVIRONMENT_SET_POINTER_CONFINEMENT: %d\n", runloop_st->pointer_confinement);
+         break;
+
       default:
          RARCH_LOG("[Environ]: UNSUPPORTED (#%u).\n", cmd);
          return false;

runloop.h

@@ -254,6 +254,7 @@ struct runloop
    unsigned subsystem_current_count;
    unsigned entry_state_slot;
    unsigned video_swap_interval_auto;
+   unsigned pointer_confinement;
 
    fastmotion_overrides_t fastmotion_override; /* float alignment */