expose analog-is-circle functionality to libretro

Author: hunterk

libretro/libretro.cpp

@@ -722,6 +722,16 @@ static void check_variables(CoreParameter &coreParam)
          g_Config.iButtonPreference = PSP_SYSTEMPARAM_BUTTON_CIRCLE;
    }
 
+   var.key = "ppsspp_analog_is_circular";
+   if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
+   {
+      if (!strcmp(var.value, "disabled"))
+         g_Config.bAnalogIsCircular = false;
+      else
+         g_Config.bAnalogIsCircular = true;
+   }
+
+
    var.key = "ppsspp_internal_resolution";
    if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
    {
@@ -1534,6 +1544,31 @@ static void retro_input(void)
    float y_left = input_state_cb(0, RETRO_DEVICE_ANALOG, RETRO_DEVICE_INDEX_ANALOG_LEFT, RETRO_DEVICE_ID_ANALOG_Y) / -32767.0f;
    float x_right = input_state_cb(0, RETRO_DEVICE_ANALOG, RETRO_DEVICE_INDEX_ANALOG_RIGHT, RETRO_DEVICE_ID_ANALOG_X) / 32767.0f;
    float y_right = input_state_cb(0, RETRO_DEVICE_ANALOG, RETRO_DEVICE_INDEX_ANALOG_RIGHT, RETRO_DEVICE_ID_ANALOG_Y) / -32767.0f;
+   
+   __CtrlSetAnalogXY(CTRL_STICK_LEFT, x_left, y_left);
+   __CtrlSetAnalogXY(CTRL_STICK_RIGHT, x_right, y_right);
+   
+   // Analog circle vs square gate compensation
+   // copied from ControlMapper.cpp's ConvertAnalogStick function
+   const bool isCircular = g_Config.bAnalogIsCircular;
+   
+   float norm = std::max(fabsf(x_left), fabsf(y_left));
+
+   if (norm == 0.0f)
+      return;
+
+   if (isCircular) {
+      float newNorm = sqrtf(x_left * x_left + y_left * y_left);
+      float factor = newNorm / norm;
+      x_left *= factor;
+      y_left *= factor;
+      norm = newNorm;
+   }
+
+   float mappedNorm = norm;
+   x_left = std::clamp(x_left / norm * mappedNorm, -1.0f, 1.0f);
+   y_left = std::clamp(y_left / norm * mappedNorm, -1.0f, 1.0f);
+   
    __CtrlSetAnalogXY(CTRL_STICK_LEFT, x_left, y_left);
    __CtrlSetAnalogXY(CTRL_STICK_RIGHT, x_right, y_right);
 }

libretro/libretro_core_options.h

@@ -261,6 +261,16 @@ struct retro_core_option_v2_definition option_defs_us[] = {
       },
       "Cross"
    },
+   {
+      "ppsspp_analog_is_circular",
+      "Analog Circle vs Square Gate Compensation",
+      NULL,
+      NULL,
+      NULL,
+      "system",
+      BOOL_OPTIONS,
+      "disabled"
+   },
    {
       "ppsspp_internal_resolution",
       "Internal Resolution (Restart)",