Support DirectInput gamepads on Windows.

content/browser/gamepad/gamepad_platform_data_fetcher_win.cc

Index: content/browser/gamepad/gamepad_platform_data_fetcher_win.cc
diff --git a/content/browser/gamepad/gamepad_platform_data_fetcher_win.cc b/content/browser/gamepad/gamepad_platform_data_fetcher_win.cc
index 838a626d0184b093df64cb1ba6a2269dd9060022..7d81496f3484288056f52c62eacde8f75884c349 100644
--- a/content/browser/gamepad/gamepad_platform_data_fetcher_win.cc
+++ b/content/browser/gamepad/gamepad_platform_data_fetcher_win.cc
@@ -4,7 +4,21 @@
 
 #include "content/browser/gamepad/gamepad_platform_data_fetcher_win.h"
 
+#define DIRECTINPUT_VERSION 0x0800
+#ifndef _WIN32_DCOM
+#define _WIN32_DCOM
+#endif
+
+#include <basetsd.h>
+#include <commctrl.h>
+#include <dinput.h>
+#include <dinputd.h>
+#include <oleauto.h>
+#include <wbemidl.h>
+#include <windows.h>
+
 #include "base/debug/trace_event.h"
+#include "base/string_util.h"
 #include "content/common/gamepad_messages.h"
 #include "content/common/gamepad_hardware_buffer.h"
 
@@ -28,7 +42,7 @@ static const BYTE kDeviceSubTypeDrumKit = 8;
 static const BYTE kDeviceSubTypeGuitarBass = 11;
 static const BYTE kDeviceSubTypeArcadePad = 19;
 
-float NormalizeAxis(SHORT value) {
+float NormalizeXInputAxis(SHORT value) {
   return ((value + 32768.f) / 32767.5f) - 1.f;
 }
 
@@ -48,105 +62,492 @@ const WebUChar* const GamepadSubTypeName(BYTE sub_type) {
   }
 }
 
+// A nicer version of the DirectX SAFE_RELEASE macro.
+template <class T>
+void SafeRelease(T** p) {
+  if (*p)
+    (*p)->Release();
+  *p = NULL;
+}
+
+bool GetDirectInputVendorProduct(IDirectInputDevice8* gamepad,
+                                 std::string* vendor,
+                                 std::string* product) {
+  DIPROPDWORD property;
+  property.diph.dwSize = sizeof(DIPROPDWORD);
+  property.diph.dwHeaderSize = sizeof(DIPROPHEADER);
+  property.diph.dwObj = 0;
+  property.diph.dwHow = DIPH_DEVICE;
+
+  if (FAILED(gamepad->GetProperty(DIPROP_VIDPID, &property.diph)))
+    return false;
+  int vendorData = LOWORD(property.dwData);
+  int productData = HIWORD(property.dwData);
+  std::stringstream vendorstream;
+  vendorstream << std::setw(4) << std::setfill('0') << std::hex << vendorData;

[scottmg, 2013/02/13 19:19:07]

http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Stream...

[teravest, 2013/02/13 21:59:22]

Done.

+  *vendor = vendorstream.str();
+
+  std::stringstream productstream;
+  productstream << std::setw(4) << std::setfill('0') << std::hex << productData;
+  *product = productstream.str();
+  return true;
+}
+
+// Sets the deadzone value for all axes of a gamepad.
+// deadzone values range from 0 (no deadzone) to 10,000 (entire range
+// is dead).
+bool SetDirectInputDeadZone(IDirectInputDevice8* gamepad,
+                            int deadzone) {
+  DIPROPDWORD prop;
+  prop.diph.dwSize = sizeof(DIPROPDWORD);
+  prop.diph.dwHeaderSize = sizeof(DIPROPHEADER);
+  prop.diph.dwObj = 0;
+  prop.diph.dwHow = DIPH_DEVICE;
+  prop.dwData = deadzone;
+  return SUCCEEDED(gamepad->SetProperty(DIPROP_DEADZONE, &prop.diph));
+}
+
+struct InternalDirectInputDevice {
+  IDirectInputDevice8* gamepad;
+  GamepadStandardMappingFunction mapper;
+  wchar_t id[WebGamepad::idLengthCap];
+};
+
+struct EnumDevicesContext {
+  std::vector<uint32>* xinput_devices;
+  IDirectInput8* directinput_interface;
+  std::vector<InternalDirectInputDevice>* directinput_devices;
+};
+
+// We have to define our own structure here; I was unable to link the
+// "global" joydata2 structure from directx. This one is smaller anyway.

[scottmg, 2013/02/13 19:19:07]

What? Why?

[teravest, 2013/02/13 21:59:22]

I didn't want to muck around with how we were linking in DirectX, and the linker
couldn't resolve c_dfDIJoystick2.

It's possible that some gamepads won't have their axes mapped well into that
structure anyway, so I think defining our own format here is reasonable. I've
updated the comment.

+struct JoyData {
+  long axes[10];
+  char buttons[24];
+  DWORD pov;  // Often used for D-pads.
+};
+
+BOOL CALLBACK DirectInputEnumDevicesCallback(const DIDEVICEINSTANCE* instance,
+                                             void* context) {
+  EnumDevicesContext* ctxt = (EnumDevicesContext*) context;
+  // Skip XInput devices.
+  for (size_t i = 0; i < ctxt->xinput_devices->size(); ++i) {
+    if ((*ctxt->xinput_devices)[i] == instance->guidProduct.Data1)
+      return DIENUM_CONTINUE;
+  }
+  IDirectInputDevice8* gamepad;
+  if (FAILED(ctxt->directinput_interface->CreateDevice(instance->guidInstance,
+                                                       &gamepad,
+                                                       NULL)))
+    return DIENUM_CONTINUE;
+
+#define MAKE_AXIS(i) \
+  {0, FIELD_OFFSET(JoyData, axes) + 4 * i, \
+   DIDFT_AXIS | DIDFT_MAKEINSTANCE(i) | DIDFT_OPTIONAL, 0}
+#define MAKE_BUTTON(i) \
+  {&GUID_Button, FIELD_OFFSET(JoyData, buttons) + i, \
+   DIDFT_BUTTON | DIDFT_MAKEINSTANCE(i) | DIDFT_OPTIONAL, 0}
+#define MAKE_POV() \
+  {&GUID_POV, FIELD_OFFSET(JoyData, pov), DIDFT_POV | DIDFT_OPTIONAL, 0}
+  DIOBJECTDATAFORMAT rgodf[] = {
+    MAKE_AXIS(0),
+    MAKE_AXIS(1),
+    MAKE_AXIS(2),
+    MAKE_AXIS(3),
+    MAKE_AXIS(4),
+    MAKE_AXIS(5),
+    MAKE_AXIS(6),
+    MAKE_AXIS(7),
+    MAKE_AXIS(8),
+    MAKE_AXIS(9),
+    MAKE_BUTTON(0),
+    MAKE_BUTTON(1),
+    MAKE_BUTTON(2),
+    MAKE_BUTTON(3),
+    MAKE_BUTTON(4),
+    MAKE_BUTTON(5),
+    MAKE_BUTTON(6),
+    MAKE_BUTTON(7),
+    MAKE_BUTTON(8),
+    MAKE_BUTTON(9),
+    MAKE_BUTTON(10),
+    MAKE_BUTTON(11),
+    MAKE_BUTTON(12),
+    MAKE_BUTTON(13),
+    MAKE_BUTTON(14),
+    MAKE_BUTTON(15),
+    MAKE_BUTTON(16),
+    MAKE_POV(),
+  };
+#undef MAKE_AXIS
+#undef MAKE_BUTTON
+#undef MAKE_POV
+
+  DIDATAFORMAT df = {
+    sizeof (DIDATAFORMAT),
+    sizeof (DIOBJECTDATAFORMAT),
+    DIDF_ABSAXIS,
+    sizeof (JoyData),
+    sizeof (rgodf) / sizeof (rgodf[0]),
+    rgodf
+  };
+
+  // If we can't set the data format on the device, don't add it to our
+  // list, since we won't know how to read data from it.
+  if (FAILED(gamepad->SetDataFormat(&df)))
+    return DIENUM_CONTINUE;
+
+  InternalDirectInputDevice device;
+  device.gamepad = gamepad;
+  std::string vendor;
+  std::string product;
+  if (!GetDirectInputVendorProduct(gamepad, &vendor, &product))
+    return DIENUM_CONTINUE;
+
+  wcscpy_s(device.id, WebGamepad::idLengthCap, instance->tszInstanceName);
+
+  SetDirectInputDeadZone(gamepad, 1000);

[scottmg, 2013/02/13 19:19:07]

Where did this 1000 come from?

[teravest, 2013/02/13 21:59:22]

I've added a comment here explaining what this is. Admittedly, 10% is a rough
guess at what's a reasonable space for a dead zone on an axis.

XInput uses by default 12% on the left stick and 13.3% on the right stick.

+  device.mapper = GetGamepadStandardMappingFunction(vendor, product);
+  if (device.mapper)
+    ctxt->directinput_devices->push_back(device);
+  return DIENUM_CONTINUE;
+}
+
+// Adapted from the DirectInput samples in the DirectX SDK.
+// http://goo.gl/53Sfw
+void FillXInputDeviceList(std::vector<uint32>* xinput_devices) {
+  xinput_devices->clear();
+  IWbemServices* pIWbemServices = NULL;
+  IEnumWbemClassObject* pEnumDevices = NULL;
+  IWbemLocator* pIWbemLocator = NULL;
+  IWbemClassObject* pDevices[20] = {0};
+  BSTR bstrDeviceID = NULL;
+  BSTR bstrClassName = NULL;
+  BSTR bstrNamespace = NULL;
+  DWORD uReturned = 0;
+  bool bCleanupCOM = false;
+  UINT iDevice = 0;
+  VARIANT var;
+  HRESULT hr;
+
+  // CoInit if needed
+  hr = CoInitialize(NULL);

[scottmg, 2013/02/13 19:19:07]

We shouldn't be doing this here.

[teravest, 2013/02/13 21:59:22]

I've changed this to use a ScopedCOMInitializer. Or are you suggesting this
shouldn't happen at all? I think I need to do this to call CoCreateInstance()
below.

+  bCleanupCOM = SUCCEEDED(hr);
+
+  // Create WMI
+  hr = CoCreateInstance(__uuidof(WbemLocator),
+                        NULL,
+                        CLSCTX_INPROC_SERVER,
+                        __uuidof(IWbemLocator),
+                        (void**)&pIWbemLocator);

[scottmg, 2013/02/13 19:19:07]

Please fix all the identifiers to match Chromium style.

[teravest, 2013/02/13 21:59:22]

Done.

+  if (FAILED(hr) || pIWbemLocator == NULL )
+    goto LCleanup;
+
+  // Create BSTRs for WMI
+  bstrNamespace = SysAllocString(L"\\\\.\\root\\cimv2");
+  if (bstrNamespace == NULL)
+    goto LCleanup;
+  bstrDeviceID = SysAllocString(L"DeviceID");
+  if (bstrDeviceID == NULL)
+    goto LCleanup;
+  bstrClassName = SysAllocString(L"Win32_PNPEntity");
+  if (bstrClassName == NULL)
+    goto LCleanup;
+
+  // Connect to WMI
+  hr = pIWbemLocator->ConnectServer(bstrNamespace, NULL, NULL, 0L,
+                                    0L, NULL, NULL, &pIWbemServices );
+  if (FAILED(hr) || pIWbemServices == NULL)
+    goto LCleanup;
+
+  // Switch security level to IMPERSONATE
+  CoSetProxyBlanket(pIWbemServices, RPC_C_AUTHN_WINNT, RPC_C_AUTHZ_NONE, NULL,
+                    RPC_C_AUTHN_LEVEL_CALL, RPC_C_IMP_LEVEL_IMPERSONATE, NULL,
+                    0);
+
+  // Get list of Win32_PNPEntity devices
+  hr = pIWbemServices->CreateInstanceEnum(bstrClassName, 0, NULL,
+                                          &pEnumDevices);
+  if (FAILED(hr) || pEnumDevices == NULL )
+    goto LCleanup;
+
+  // Loop over all devices
+  while (true) {
+    // Get 20 at a time
+    hr = pEnumDevices->Next(10000, 20, pDevices, &uReturned);
+    if (FAILED(hr))
+      goto LCleanup;
+    if (uReturned == 0)
+      break;
+
+    for (iDevice = 0; iDevice < uReturned; iDevice++) {
+      if (!pDevices[iDevice])
+        continue;
+      // For each device, get its device ID
+      hr = pDevices[iDevice]->Get(bstrDeviceID, 0L, &var, NULL, NULL);
+      if (SUCCEEDED(hr) && var.vt == VT_BSTR && var.bstrVal != NULL) {
+        // Check if the device ID contains "IG_".  If it does, then it's an
+        // XInput device
+        // Unfortunately this information can not be found by just using
+        // DirectInput
+        if (wcsstr(var.bstrVal, L"IG_")) {
+          // If it does, then get the VID/PID from var.bstrVal
+          DWORD dwPid = 0, dwVid = 0;
+          WCHAR* strVid = wcsstr(var.bstrVal, L"VID_");
+          if (strVid && swscanf(strVid, L"VID_%4X", &dwVid) != 1)
+            dwVid = 0;
+          WCHAR* strPid = wcsstr(var.bstrVal, L"PID_");
+          if (strPid && swscanf(strPid, L"PID_%4X", &dwPid) != 1)
+            dwPid = 0;
+          DWORD dwVidPid = MAKELONG(dwVid, dwPid);
+
+          // Add the VID/PID to a linked list
+          xinput_devices->push_back(dwVidPid);
+        }
+      }
+      SafeRelease(&pDevices[iDevice]);
+    }
+  }
+
+LCleanup:
+  if (bstrNamespace)
+    SysFreeString(bstrNamespace);
+  if (bstrDeviceID)
+    SysFreeString(bstrDeviceID);
+  if (bstrClassName)
+    SysFreeString(bstrClassName);
+  for (iDevice = 0; iDevice < 20; iDevice++)
+    SafeRelease(&pDevices[iDevice]);
+  SafeRelease(&pEnumDevices);
+  SafeRelease(&pIWbemLocator);
+  SafeRelease(&pIWbemServices);
+}
+
 }  // namespace
 
 GamepadPlatformDataFetcherWin::GamepadPlatformDataFetcherWin()
     : xinput_dll_(FilePath(FILE_PATH_LITERAL("xinput1_3.dll"))),
-      xinput_available_(GetXinputDllFunctions()) {
+      xinput_available_(GetXInputDllFunctions()),
+      directinput_dll_(FilePath(FILE_PATH_LITERAL("dinput8.dll"))),
+      directinput_available_(GetDirectInputDllFunctions()) {
 }
 
 GamepadPlatformDataFetcherWin::~GamepadPlatformDataFetcherWin() {
 }
 
+void GamepadPlatformDataFetcherWin::EnumerateDevices(
+    WebGamepads* pads) {
+  TRACE_EVENT0("GAMEPAD", "EnumerateDevices");
+  pad_state_.clear();
+  for (unsigned i = 0; i < WebGamepads::itemsLengthCap; ++i) {
+    PadState s;
+    s.status = DISCONNECTED;
+    pad_state_.push_back(s);
+  }
+
+  for (unsigned i = 0; i < WebGamepads::itemsLengthCap; ++i) {
+    WebGamepad &pad = pads->items[i];
+    if (xinput_available_ && GetXInputPadConnectivity(i, &pad)) {
+      pad_state_[i].status = XINPUT_CONNECTED;
+      continue;
+    }
+  }
+
+  if (directinput_available_) {
+    FillXInputDeviceList(&xinput_devices_);
+    struct EnumDevicesContext ctxt;
+    std::vector<InternalDirectInputDevice> directinput_gamepads;
+    ctxt.xinput_devices = &xinput_devices_;
+    ctxt.directinput_interface = directinput_interface_;
+    ctxt.directinput_devices = &directinput_gamepads;
+
+    directinput_interface_->EnumDevices(
+        DI8DEVCLASS_GAMECTRL,
+        &DirectInputEnumDevicesCallback,
+        &ctxt,
+        DIEDFL_ATTACHEDONLY);
+
+    // Fill the "disconnected" pad state entries with our DirectInput
+    // gamepads.
+    unsigned pad_state_index = 0;
+    unsigned directinput_index = 0;
+    while (pad_state_index < WebGamepads::itemsLengthCap &&
+           directinput_index < directinput_gamepads.size()) {
+      if (pad_state_[pad_state_index].status != DISCONNECTED) {
+        ++pad_state_index;
+        continue;
+      }
+      WebGamepad &pad = pads->items[pad_state_index];
+      pad.connected = true;
+      wcscpy_s(pad.id, WebGamepad::idLengthCap,
+               directinput_gamepads[directinput_index].id);
+      pad_state_[pad_state_index].status = DIRECTINPUT_CONNECTED;
+      pad_state_[pad_state_index].directinput_gamepad =
+          directinput_gamepads[directinput_index].gamepad;
+      pad_state_[pad_state_index].mapper =
+          directinput_gamepads[directinput_index].mapper;
+      ++directinput_index;
+      ++pad_state_index;
+    }
+  }
+}
+
+
 void GamepadPlatformDataFetcherWin::GetGamepadData(WebGamepads* pads,
-                                        bool devices_changed_hint) {
+                                                   bool devices_changed_hint) {
   TRACE_EVENT0("GAMEPAD", "GetGamepadData");
 
-  // If there's no XInput DLL on the system, early out so that we don't
-  // call any other XInput functions.
-  if (!xinput_available_) {
+  if (!xinput_available_ && !directinput_available_) {
     pads->length = 0;
     return;
   }
 
-  pads->length = WebGamepads::itemsLengthCap;
-
+  // A note on XInput devices:
   // If we got notification that system devices have been updated, then
   // run GetCapabilities to update the connected status and the device
   // identifier. It can be slow to do to both GetCapabilities and
   // GetState on unconnected devices, so we want to avoid a 2-5ms pause
   // here by only doing this when the devices are updated (despite
   // documentation claiming it's OK to call it any time).
-  if (devices_changed_hint) {
-    for (unsigned i = 0; i < WebGamepads::itemsLengthCap; ++i) {
-      WebGamepad& pad = pads->items[i];
-      TRACE_EVENT1("GAMEPAD", "GetCapabilities", "id", i);
-      XINPUT_CAPABILITIES caps;
-      DWORD res = xinput_get_capabilities_(i, XINPUT_FLAG_GAMEPAD, &caps);
-      if (res == ERROR_DEVICE_NOT_CONNECTED) {
-        pad.connected = false;
-      } else {
-        pad.connected = true;
-        base::swprintf(pad.id,
-                       WebGamepad::idLengthCap,
-                       L"Xbox 360 Controller (XInput STANDARD %ls)",
-                       GamepadSubTypeName(caps.SubType));
-      }
-    }
-  }
+  if (devices_changed_hint)
+    EnumerateDevices(pads);
 
-  // We've updated the connection state if necessary, now update the actual
-  // data for the devices that are connected.
   for (unsigned i = 0; i < WebGamepads::itemsLengthCap; ++i) {
     WebGamepad& pad = pads->items[i];
+    if (pad_state_[i].status == XINPUT_CONNECTED)
+      GetXInputPadData(i, &pad);
+    else if (pad_state_[i].status == DIRECTINPUT_CONNECTED)
+      GetDirectInputPadData(i, &pad);
+  }
+  pads->length = WebGamepads::itemsLengthCap;
+  return;

[scottmg, 2013/02/13 19:19:07]

nit: remove

[teravest, 2013/02/13 21:59:22]

Done.

+}
 
-    // We rely on device_changed and GetCapabilities to tell us that
-    // something's been connected, but we will mark as disconnected if
-    // GetState returns that we've lost the pad.
-    if (!pad.connected)
-      continue;
+bool GamepadPlatformDataFetcherWin::GetXInputPadConnectivity(
+    int i,
+    WebGamepad* pad) const {
+  DCHECK(pad);
+  TRACE_EVENT1("GAMEPAD", "GetXInputPadConnectivity", "id", i);
+  XINPUT_CAPABILITIES caps;
+  DWORD res = xinput_get_capabilities_(i, XINPUT_FLAG_GAMEPAD, &caps);
+  if (res == ERROR_DEVICE_NOT_CONNECTED) {
+    pad->connected = false;
+    return false;
+  } else {
+    pad->connected = true;
+    base::swprintf(pad->id,
+                   WebGamepad::idLengthCap,
+                   L"Xbox 360 Controller (XInput STANDARD %ls)",
+                   GamepadSubTypeName(caps.SubType));
+    return true;
+  }
+}
+
+void GamepadPlatformDataFetcherWin::GetXInputPadData(
+    int i,
+    WebGamepad* pad) {
+  // We rely on device_changed and GetCapabilities to tell us that
+  // something's been connected, but we will mark as disconnected if
+  // GetState returns that we've lost the pad.
+  if (!pad->connected)
+    return;
 
-    XINPUT_STATE state;
-    memset(&state, 0, sizeof(XINPUT_STATE));
-    TRACE_EVENT_BEGIN1("GAMEPAD", "XInputGetState", "id", i);
-    DWORD dwResult = xinput_get_state_(i, &state);
-    TRACE_EVENT_END1("GAMEPAD", "XInputGetState", "id", i);
-
-    if (dwResult == ERROR_SUCCESS) {
-      pad.timestamp = state.dwPacketNumber;
-      pad.buttonsLength = 0;
-#define ADD(b) pad.buttons[pad.buttonsLength++] = \
-    ((state.Gamepad.wButtons & (b)) ? 1.0 : 0.0);
-      ADD(XINPUT_GAMEPAD_A);
-      ADD(XINPUT_GAMEPAD_B);
-      ADD(XINPUT_GAMEPAD_X);
-      ADD(XINPUT_GAMEPAD_Y);
-      ADD(XINPUT_GAMEPAD_LEFT_SHOULDER);
-      ADD(XINPUT_GAMEPAD_RIGHT_SHOULDER);
-      pad.buttons[pad.buttonsLength++] = state.Gamepad.bLeftTrigger / 255.0;
-      pad.buttons[pad.buttonsLength++] = state.Gamepad.bRightTrigger / 255.0;
-      ADD(XINPUT_GAMEPAD_BACK);
-      ADD(XINPUT_GAMEPAD_START);
-      ADD(XINPUT_GAMEPAD_LEFT_THUMB);
-      ADD(XINPUT_GAMEPAD_RIGHT_THUMB);
-      ADD(XINPUT_GAMEPAD_DPAD_UP);
-      ADD(XINPUT_GAMEPAD_DPAD_DOWN);
-      ADD(XINPUT_GAMEPAD_DPAD_LEFT);
-      ADD(XINPUT_GAMEPAD_DPAD_RIGHT);
+  XINPUT_STATE state;
+  memset(&state, 0, sizeof(XINPUT_STATE));
+  TRACE_EVENT_BEGIN1("GAMEPAD", "XInputGetState", "id", i);
+  DWORD dwResult = xinput_get_state_(i, &state);
+  TRACE_EVENT_END1("GAMEPAD", "XInputGetState", "id", i);
+
+  if (dwResult == ERROR_SUCCESS) {
+    pad->timestamp = state.dwPacketNumber;
+    pad->buttonsLength = 0;
+#define ADD(b) pad->buttons[pad->buttonsLength++] = \
+  ((state.Gamepad.wButtons & (b)) ? 1.0 : 0.0);
+    ADD(XINPUT_GAMEPAD_A);
+    ADD(XINPUT_GAMEPAD_B);
+    ADD(XINPUT_GAMEPAD_X);
+    ADD(XINPUT_GAMEPAD_Y);
+    ADD(XINPUT_GAMEPAD_LEFT_SHOULDER);
+    ADD(XINPUT_GAMEPAD_RIGHT_SHOULDER);
+    pad->buttons[pad->buttonsLength++] = state.Gamepad.bLeftTrigger / 255.0;
+    pad->buttons[pad->buttonsLength++] = state.Gamepad.bRightTrigger / 255.0;
+    ADD(XINPUT_GAMEPAD_BACK);
+    ADD(XINPUT_GAMEPAD_START);
+    ADD(XINPUT_GAMEPAD_LEFT_THUMB);
+    ADD(XINPUT_GAMEPAD_RIGHT_THUMB);
+    ADD(XINPUT_GAMEPAD_DPAD_UP);
+    ADD(XINPUT_GAMEPAD_DPAD_DOWN);
+    ADD(XINPUT_GAMEPAD_DPAD_LEFT);
+    ADD(XINPUT_GAMEPAD_DPAD_RIGHT);
 #undef ADD
-      pad.axesLength = 0;
-      // XInput are +up/+right, -down/-left, we want -up/-left.
-      pad.axes[pad.axesLength++] = NormalizeAxis(state.Gamepad.sThumbLX);
-      pad.axes[pad.axesLength++] = -NormalizeAxis(state.Gamepad.sThumbLY);
-      pad.axes[pad.axesLength++] = NormalizeAxis(state.Gamepad.sThumbRX);
-      pad.axes[pad.axesLength++] = -NormalizeAxis(state.Gamepad.sThumbRY);
-    } else {
-      pad.connected = false;
-    }
+    pad->axesLength = 0;
+    // XInput are +up/+right, -down/-left, we want -up/-left.
+    pad->axes[pad->axesLength++] = NormalizeXInputAxis(state.Gamepad.sThumbLX);
+    pad->axes[pad->axesLength++] = -NormalizeXInputAxis(state.Gamepad.sThumbLY);
+    pad->axes[pad->axesLength++] = NormalizeXInputAxis(state.Gamepad.sThumbRX);
+    pad->axes[pad->axesLength++] = -NormalizeXInputAxis(state.Gamepad.sThumbRY);
+  } else {
+    pad->connected = false;
   }
 }
 
-bool GamepadPlatformDataFetcherWin::GetXinputDllFunctions() {
+void GamepadPlatformDataFetcherWin::GetDirectInputPadData(
+    int index,
+    WebGamepad* pad) {
+  if (!pad->connected)
+    return;
+
+  IDirectInputDevice8* gamepad = pad_state_[index].directinput_gamepad;
+  if (FAILED(gamepad->Poll())) {
+    HRESULT hr;
+    while ((hr = gamepad->Acquire()) == DIERR_INPUTLOST) { }
+    return;
+  }
+
+  JoyData state;
+  if (FAILED(gamepad->GetDeviceState(sizeof(JoyData), &state))) {
+    pad->connected = false;
+    return;
+  }
+
+  WebGamepad raw;
+  raw.connected = true;
+  for (int i = 0; i < 16; i++)
+    raw.buttons[i] = (state.buttons[i] & 0x80) ? 1.0 : 0.0;
+
+  // We map the POV (often a D-pad) into the buttons 16-19.
+  // DirectInput gives pov measurements in hundredths of degrees,
+  // clockwise from "North".
+  // We use 22.5 degree slices so we can handle diagonal D-raw presses.
+  static const int arc_segment = 2250;  // 22.5 degrees = 1/16 circle
+  if (state.pov > arc_segment && state.pov < 7 * arc_segment)
+    raw.buttons[19] = 1;
+  else
+    raw.buttons[19] = 0;
+
+  if (state.pov > 5 * arc_segment && state.pov < 11 * arc_segment)
+    raw.buttons[17] = 1;
+  else
+    raw.buttons[17] = 0;
+
+  if (state.pov > 9 * arc_segment && state.pov < 15 * arc_segment)
+    raw.buttons[18] = 1;
+  else
+    raw.buttons[18] = 0;
+
+  if (state.pov < 3 * arc_segment ||
+      (state.pov > 13 * arc_segment && state.pov < 36000))
+    raw.buttons[16] = 1;
+  else
+    raw.buttons[16] = 0;
+
+  for (int i = 0; i < 10; i++)
+    raw.axes[i] = state.axes[i];
+
+  pad_state_[index].mapper(raw, pad);
+}
+
+bool GamepadPlatformDataFetcherWin::GetXInputDllFunctions() {
   xinput_get_capabilities_ = NULL;
   xinput_get_state_ = NULL;
   xinput_enable_ = static_cast<XInputEnableFunc>(
@@ -165,4 +566,18 @@ bool GamepadPlatformDataFetcherWin::GetXinputDllFunctions() {
   return true;
 }
 
+bool GamepadPlatformDataFetcherWin::GetDirectInputDllFunctions() {
+  directinput_create_ = static_cast<DirectInputCreateFunc>(

[scottmg, 2013/02/13 19:19:07]

According to
http://msdn.microsoft.com/en-us/library/windows/desktop/ee416805(v=vs.85).aspx
dinput has shipped and hasn't changed since xpsp2, so there's no reason not to
link directly, rather than doing late binding.

[teravest, 2013/02/13 21:59:22]

Cool. I'm still trying to figure out how to do this, I haven't been able to link
directly yet, but I'll play with the gyp files some more.

+      directinput_dll_.GetFunctionPointer("DirectInput8Create"));
+  if (!directinput_create_)
+    return false;
+  if (FAILED(directinput_create_(GetModuleHandle(NULL),
+                                 DIRECTINPUT_VERSION,
+                                 IID_IDirectInput8,
+                                 (void **)&directinput_interface_,
+                                 NULL)))
+    return false;
+  return true;
+}
+
 }  // namespace content