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Wii Motion Plus Fixed #260

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Wii Motion Plus Fixed #260

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2af6564
Add WPAD_HasMotionPlus function to check MotionPlus
gitman123323 Mar 23, 2026
5ecf16a
Update motion_plus.c
gitman123323 Mar 23, 2026
f3313c7
Add MotionPlus support to wpad.h
gitman123323 Mar 23, 2026
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3 changes: 3 additions & 0 deletions gc/wiiuse/wpad.h
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Original file line number Diff line number Diff line change
Expand Up @@ -228,6 +228,9 @@ void WPAD_Expansion(int chan, struct expansion_t *exp);
void WPAD_PadStatus(int chan);
bool WPAD_IsBatteryCritical(int chan);

s32 WPAD_HasMotionPlus(s32 chan);
#define WPAD_EXP_MOTION_PLUS 5
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@DacoTaco DacoTaco Mar 23, 2026

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unused define?

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@gitman123323 gitman123323 Mar 23, 2026

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The #define WPAD_EXP_MOTION_PLUS 5 is important because it exposes Motion Plus as an official public API constant. Now that Motion Plus actually works, external code needs to know what the value 5 represents. Without it in the header, 5 stays an undocumented magic number. The constant makes Motion Plus a discoverable, documented part of the API.

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@mardy mardy Mar 23, 2026

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Please don't add this: we already have EXP_MOTION_PLUS defined in a public header, and there's a way of checking if the motion plus is available, using the currently public API: just check the exp.type field of the WPADData structure.

If you really want to make it even more convenient, you could add this to the wpad.h header:

static inline bool WPAD_HasMotionPlus(s32 chan) {
     return WPAD_Data(chan)->exp.type == EXP_MOTION_PLUS;
}

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@gitman123323 gitman123323 Mar 24, 2026 •
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Hi mardy,

Just to clarify what my new code actually does: it ensures that the Wii MotionPlus can be reliably detected as physically present using libogc. Before these changes, detection wasn’t consistent, and the gyroscope values from MotionPlus were all zeros, so motion data wasn’t accessible at all. With my fixes, the MotionPlus now responds correctly to motion, and developers can safely detect and use it.

That’s why I added the new header — it’s directly tied to these fixes and makes the feature work reliably in practice.

Thanks for taking a look.


#ifdef __cplusplus
}
#endif /* __cplusplus */
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4 changes: 2 additions & 2 deletions wiiuse/motion_plus.c
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Expand Up @@ -30,7 +30,7 @@ static void wiiuse_probe_motion_plus_check2(struct wiimote_t *wm, ubyte *data, u

static void wiiuse_probe_motion_plus_check1(struct wiimote_t *wm, ubyte *data, uword len)
{
if (data[1] != 0x05)
if (data[5] != 0x05)
{
WIIMOTE_DISABLE_STATE(wm, WIIMOTE_STATE_MPLUS_PRESENT);
WIIMOTE_DISABLE_STATE(wm, WIIMOTE_STATE_EXP_HANDSHAKE);
Expand All @@ -45,7 +45,7 @@ static void wiiuse_probe_motion_plus_check1(struct wiimote_t *wm, ubyte *data, u
void wiiuse_probe_motion_plus(struct wiimote_t *wm)
{
ubyte *buf = __lwp_wkspace_allocate(MAX_PAYLOAD);
wiiuse_read_data(wm, buf, WM_EXP_MOTION_PLUS_MODE, 2, wiiuse_probe_motion_plus_check1);
wiiuse_read_data(wm, buf, WM_EXP_ID, 6, wiiuse_probe_motion_plus_check1);
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@mardy mardy Mar 23, 2026

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I haven't test this very code in libogc, but when I ported it in my wpad2 branch I followed the same logic and it was working fine. Are you sure that the old code is not working?

Also, according to the documentation, the old code is correct, because the motion plus, until you activate it, is found at 0xA60000: https://wiibrew.org/wiki/Wiimote/Extension_Controllers/Wii_Motion_Plus

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@gitman123323 gitman123323 Mar 23, 2026

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Hey, just to make sure we're talking about the same thing — if you mean Motion Plus connectivity, yeah that might be fine. What I'm fixing here is actually reading the gyro data, because right now the values just come back as 0.00 no matter what even when Motion Plus is attached and active. That's the bug I ran into and what this PR addresses. Maybe we were just confused about which problem we were each referring to?

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@gitman123323 gitman123323 Mar 24, 2026

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Because i mean, could you clarify what you were talking about? because what my new code fixes is the following: wii motion plus can now be detected as wheter it is physically present or not using libogc and it also now allow access to the wii motion plus gyros which weren't accessible at all before because the values returned all zeros and now they actually respond to motion correctly.

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@mardy mardy Mar 24, 2026

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Hi! Let's try to address one issue at a time, since your PR seems to relate to several different issues.

With the unmodified libogc, is the motion plus detected correctly? I mean, what is the value of WPAD_Data(chan)->exp.type, if you connect the Motion plus? And does this change, if you call WPAD_SetMotionPlus(chan, true)?

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@gitman123323 gitman123323 Mar 25, 2026

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the value of WPAD_Data(chan)->exp.type returns nothing because i don't know, somehow it doesn't work right, and also yes directly setting WPAD_SetMotionPlus(chan, true) does do something but it's just forcefully telling the system that there is a motion plus present when there isn't one, not actually detecting wheter it got connected to the wiimote or not. Does that help you?

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@mardy mardy Mar 25, 2026

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Mmm... Are you calling WPAD_ScanPads() at every frame? This is the function responsible for updating the wiimotes structures.

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@gitman123323 gitman123323 Mar 25, 2026 •
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Yes, I am calling WPAD_ScanPads() every frame as expected, and all standard input handling works correctly (Wiimote buttons, Nunchuk detection, etc.).

The issue seems to be specific to Wii MotionPlus. Before applying my changes, MotionPlus could not be reliably detected or used, even though the rest of the input system behaved normally.

From my testing, this appears to be unrelated to how often PAD_ScanPads() is called, and more likely tied to how MotionPlus data or registers are currently handled in libogc. After patching the relevant parts, MotionPlus detection and usage started working as expected.

I really appreciate you taking the time to look into this.

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@gitman123323 gitman123323 Mar 26, 2026 •
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Here are some showcase videos demonstrating the fix working in real time:

https://youtube.com/shorts/dbdM1a0HkyI?feature=share

https://youtube.com/shorts/va6WUNGnWXY?feature=share

}

void wiiuse_motion_plus_check(struct wiimote_t *wm,ubyte *data,uword len)
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9 changes: 8 additions & 1 deletion wiiuse/wpad.c
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Expand Up @@ -89,7 +89,7 @@ static vs32 __wpads_bonded = 0;
static u32 __wpad_idletimeout = 300;
static vu32 __wpads_active = 0;
static vu32 __wpads_used = 0;
static wiimote **__wpads = NULL;
wiimote **__wpads = NULL;
static wiimote_listen __wpads_listen[WPAD_MAX_DEVICES] = {0};
static WPADData wpaddata[WPAD_MAX_DEVICES] = {0};
static struct _wpad_cb __wpdcb[WPAD_MAX_DEVICES] = {0};
Expand Down Expand Up @@ -2046,3 +2046,10 @@ bool WPAD_IsBatteryCritical(int chan)
if(chan<0 || chan>=WPAD_MAX_DEVICES) return false;
return WIIMOTE_IS_SET(__wpads[chan],WIIMOTE_STATE_BATTERY_CRITICAL);
}

int WPAD_HasMotionPlus(s32 chan) {
if (__wpads && __wpads[chan]) __wpads[chan]->state &= ~0x000020;
if (__wpads == NULL) return 0;
if (__wpads[chan] == NULL) return 0;
return (__wpads[chan]->state & 0x100000) ? 1 : 0;
}
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