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fix: touch translator pan/pinch mode-lock, DPI-scaled thresholds, main-menu first-tap #15

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fix: touch translator pan/pinch mode-lock, DPI-scaled thresholds, main-menu first-tap #15

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7 changes: 7 additions & 0 deletions GeneralsMD/Code/GameEngine/Source/GameClient/GUI/GUICallbacks/Menus/MainMenu.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,9 @@
#include "GameClient/GadgetPushButton.h"
#include <SDL3/SDL.h>
#endif
#if defined(__APPLE__)
#include <TargetConditionals.h>
#endif


// PRIVATE DATA ///////////////////////////////////////////////////////////////////////////////////
Expand Down Expand Up @@ -1057,6 +1060,10 @@ WindowMsgHandledType MainMenuInput( GameWindow *window, UnsignedInt msg,
{
// TheSuperHackers @tweak 26/02/2026 Show mouse and menu immediately when shellmap is disabled.
Bool doShow = !TheGlobalData->m_shellMapOn;
#if defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE
// GeneralsX @bugfix Codex 09/07/2026 Touch has no idle mouse travel before the first tap, so reveal the main menu on first hover.
doShow = TRUE;
#endif

if (!doShow)
{
Expand Down
172 changes: 137 additions & 35 deletions GeneralsMD/Code/GameEngineDevice/Source/SDL3GameEngine.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -139,9 +139,11 @@ struct TouchState {
enum Phase {
IDLE, // no fingers tracked
PENDING, // finger1 down, gesture identity not yet known, nothing sent
TWO_PENDING, // two fingers down, waiting to lock pan vs pinch
DRAGGING, // finger1 drag in progress, LMB held
LONGPRESSED, // long-press fired (RMB click sent), swallow until lift
PAN // two-finger camera pan, RMB held
PAN, // two-finger camera pan, RMB held
PINCH // two-finger zoom, no mouse button held
};

Phase phase = IDLE;
Expand All @@ -150,6 +152,8 @@ struct TouchState {
float downX = 0.0f, downY = 0.0f; // finger1 down position (window points)
float lastX = 0.0f, lastY = 0.0f; // finger1 latest position
float panX = 0.0f, panY = 0.0f; // pan centroid
float twoStartX = 0.0f, twoStartY = 0.0f;
float twoStartDist = 0.0f;
float pinchDist = 0.0f; // finger distance at last wheel step
Uint64 downTicks = 0;
float f1x = 0.0f, f1y = 0.0f, f2x = 0.0f, f2y = 0.0f; // normalized per finger
Expand All @@ -158,8 +162,59 @@ struct TouchState {
TouchState s_touch;

const Uint64 LONG_PRESS_MS = 600;
const float PINCH_STEP_RATIO = 0.06f; // 6% distance change per wheel tick
const float TAP_DEAD_ZONE_PX = 8.0f; // jitter below this keeps a tap a tap
// GeneralsX @bugfix Codex 09/07/2026 Lock two-finger gestures and scale touch thresholds to physical display density.
const float PINCH_STEP_RATIO = 0.03f; // 3% distance change per wheel tick
const float MIN_TOUCH_DEAD_ZONE_PX = 8.0f; // low-density floor for tap/pan/pinch jitter
const float TOUCH_DEAD_ZONE_MM = 3.0f;
const float SDL_BASE_POINTS_PER_MM = 160.0f / 25.4f;

float getTouchDeadZonePx(SDL_Window *window)
{
static bool initialized = false;
static float deadZonePx = MIN_TOUCH_DEAD_ZONE_PX;

if (!initialized) {
if (window) {
const SDL_DisplayID display = SDL_GetDisplayForWindow(window);
if (display != 0) {
const float contentScale = SDL_GetDisplayContentScale(display);
if (contentScale > 0.0f) {
const float physicalPx = TOUCH_DEAD_ZONE_MM * SDL_BASE_POINTS_PER_MM * contentScale;
if (physicalPx > deadZonePx) {
deadZonePx = physicalPx;
}
}
}
}
initialized = true;
}

return deadZonePx;
}

float getCentroidX(int winW)
{
return (s_touch.f1x + s_touch.f2x) * 0.5f * (float)winW;
}

float getCentroidY(int winH)
{
return (s_touch.f1y + s_touch.f2y) * 0.5f * (float)winH;
}

float getFingerDistance(int winW, int winH)
{
const float dx = (s_touch.f1x - s_touch.f2x) * (float)winW;
const float dy = (s_touch.f1y - s_touch.f2y) * (float)winH;
return SDL_sqrtf(dx * dx + dy * dy);
}

bool isTwoFingerPhase()
{
return s_touch.phase == TouchState::TWO_PENDING ||
s_touch.phase == TouchState::PAN ||
s_touch.phase == TouchState::PINCH;
}

void sendSyntheticMouse(SDL3Mouse *mouse, SDL_Window *window, Uint32 type,
float x, float y, Uint8 button = 0, float wheelY = 0.0f)
Expand Down Expand Up @@ -200,17 +255,67 @@ void sendSyntheticMouse(SDL3Mouse *mouse, SDL_Window *window, Uint32 type,

void beginPan(SDL3Mouse *mouse, SDL_Window *window, int winW, int winH)
{
s_touch.panX = (s_touch.f1x + s_touch.f2x) * 0.5f * (float)winW;
s_touch.panY = (s_touch.f1y + s_touch.f2y) * 0.5f * (float)winH;
const float dx = (s_touch.f1x - s_touch.f2x) * (float)winW;
const float dy = (s_touch.f1y - s_touch.f2y) * (float)winH;
s_touch.pinchDist = SDL_sqrtf(dx * dx + dy * dy);
s_touch.panX = getCentroidX(winW);
s_touch.panY = getCentroidY(winH);
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_MOTION, s_touch.panX, s_touch.panY);
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_BUTTON_DOWN,
s_touch.panX, s_touch.panY, SDL_BUTTON_RIGHT);
s_touch.phase = TouchState::PAN;
}

void beginTwoFingerPending(int winW, int winH)
{
s_touch.twoStartX = getCentroidX(winW);
s_touch.twoStartY = getCentroidY(winH);
s_touch.twoStartDist = getFingerDistance(winW, winH);
s_touch.panX = s_touch.twoStartX;
s_touch.panY = s_touch.twoStartY;
s_touch.pinchDist = s_touch.twoStartDist;
s_touch.phase = TouchState::TWO_PENDING;
}

void handlePinch(SDL3Mouse *mouse, SDL_Window *window, int winW, int winH)
{
const float dist = getFingerDistance(winW, winH);
if (s_touch.pinchDist > 1.0f) {
const float ratio = dist / s_touch.pinchDist;
const float cx = getCentroidX(winW);
const float cy = getCentroidY(winH);
if (ratio > 1.0f + PINCH_STEP_RATIO) {
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_WHEEL, cx, cy, 0, 1.0f);
s_touch.pinchDist = dist;
} else if (ratio < 1.0f - PINCH_STEP_RATIO) {
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_WHEEL, cx, cy, 0, -1.0f);
s_touch.pinchDist = dist;
}
}
}

void classifyTwoFingerGesture(SDL3Mouse *mouse, SDL_Window *window, int winW, int winH)
{
const float cx = getCentroidX(winW);
const float cy = getCentroidY(winH);
const float dist = getFingerDistance(winW, winH);
const float panDx = cx - s_touch.twoStartX;
const float panDy = cy - s_touch.twoStartY;
const float panTravel = SDL_sqrtf(panDx * panDx + panDy * panDy);
const float pinchTravel = SDL_fabsf(dist - s_touch.twoStartDist);
const float threshold = getTouchDeadZonePx(window);
const bool panReady = panTravel >= threshold;
const bool pinchReady = pinchTravel >= threshold;

if (!panReady && !pinchReady) {
return;
}

if (panReady && (!pinchReady || panTravel >= pinchTravel)) {
beginPan(mouse, window, winW, winH);
} else {
s_touch.phase = TouchState::PINCH;
handlePinch(mouse, window, winW, winH);
}
}

void handleTouchEvent(SDL3Mouse *mouse, SDL_Window *window, const SDL_Event &event)
{
int winW = 0, winH = 0;
Expand Down Expand Up @@ -243,23 +348,24 @@ void handleTouchEvent(SDL3Mouse *mouse, SDL_Window *window, const SDL_Event &eve
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_MOTION, px, py);
}
else if (s_touch.phase == TouchState::PENDING) {
// Second finger before the first committed to anything: pure pan,
// no left-click ever happened.
// Second finger before the first committed to anything: wait for
// physical movement to decide pan vs pinch, no left-click happened.
s_touch.finger2 = event.tfinger.fingerID;
s_touch.f2x = event.tfinger.x;
s_touch.f2y = event.tfinger.y;
beginPan(mouse, window, winW, winH);
beginTwoFingerPending(winW, winH);
}
else if (s_touch.phase == TouchState::DRAGGING) {
// Second finger during a live drag: finish the drag-box, then pan.
// Second finger during a live drag: finish the drag-box, then wait
// for physical movement to decide pan vs pinch.
s_touch.finger2 = event.tfinger.fingerID;
s_touch.f2x = event.tfinger.x;
s_touch.f2y = event.tfinger.y;
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_BUTTON_UP,
s_touch.lastX, s_touch.lastY, SDL_BUTTON_LEFT);
beginPan(mouse, window, winW, winH);
beginTwoFingerPending(winW, winH);
}
// LONGPRESSED / PAN with extra fingers: ignored
// LONGPRESSED / TWO_PENDING / PAN / PINCH with extra fingers: ignored
break;

case SDL_EVENT_FINGER_MOTION:
Expand All @@ -268,16 +374,18 @@ void handleTouchEvent(SDL3Mouse *mouse, SDL_Window *window, const SDL_Event &eve
s_touch.f1y = event.tfinger.y;
s_touch.lastX = px;
s_touch.lastY = py;
} else if (s_touch.phase == TouchState::PAN && event.tfinger.fingerID == s_touch.finger2) {
} else if (isTwoFingerPhase() && event.tfinger.fingerID == s_touch.finger2) {
s_touch.f2x = event.tfinger.x;
s_touch.f2y = event.tfinger.y;
} else {
break;
}

if (s_touch.phase == TouchState::PENDING && event.tfinger.fingerID == s_touch.finger1) {
const float moved = SDL_fabsf(px - s_touch.downX) + SDL_fabsf(py - s_touch.downY);
if (moved >= TAP_DEAD_ZONE_PX) {
const float dx = px - s_touch.downX;
const float dy = py - s_touch.downY;
const float moved = SDL_sqrtf(dx * dx + dy * dy);
if (moved >= getTouchDeadZonePx(window)) {
// Commit to a drag: anchor the LMB at the original touch point so
// drag-boxes start where the finger first landed.
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_MOTION, s_touch.downX, s_touch.downY);
Expand All @@ -290,33 +398,25 @@ void handleTouchEvent(SDL3Mouse *mouse, SDL_Window *window, const SDL_Event &eve
else if (s_touch.phase == TouchState::DRAGGING && event.tfinger.fingerID == s_touch.finger1) {
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_MOTION, px, py);
}
else if (s_touch.phase == TouchState::TWO_PENDING) {
classifyTwoFingerGesture(mouse, window, winW, winH);
}
else if (s_touch.phase == TouchState::PAN) {
const float cx = (s_touch.f1x + s_touch.f2x) * 0.5f * (float)winW;
const float cy = (s_touch.f1y + s_touch.f2y) * 0.5f * (float)winH;
const float cx = getCentroidX(winW);
const float cy = getCentroidY(winH);
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_MOTION, cx, cy);
s_touch.panX = cx;
s_touch.panY = cy;

const float dx = (s_touch.f1x - s_touch.f2x) * (float)winW;
const float dy = (s_touch.f1y - s_touch.f2y) * (float)winH;
const float dist = SDL_sqrtf(dx * dx + dy * dy);
if (s_touch.pinchDist > 1.0f) {
const float ratio = dist / s_touch.pinchDist;
if (ratio > 1.0f + PINCH_STEP_RATIO) {
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_WHEEL, cx, cy, 0, 1.0f);
s_touch.pinchDist = dist;
} else if (ratio < 1.0f - PINCH_STEP_RATIO) {
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_WHEEL, cx, cy, 0, -1.0f);
s_touch.pinchDist = dist;
}
}
}
else if (s_touch.phase == TouchState::PINCH) {
handlePinch(mouse, window, winW, winH);
}
break;

case SDL_EVENT_FINGER_UP:
case SDL_EVENT_FINGER_CANCELED:
if (event.tfinger.fingerID != s_touch.finger1 &&
!(s_touch.phase == TouchState::PAN && event.tfinger.fingerID == s_touch.finger2)) {
!(isTwoFingerPhase() && event.tfinger.fingerID == s_touch.finger2)) {
break;
}
switch (s_touch.phase) {
Expand All @@ -341,6 +441,9 @@ void handleTouchEvent(SDL3Mouse *mouse, SDL_Window *window, const SDL_Event &eve
sendSyntheticMouse(mouse, window, SDL_EVENT_MOUSE_BUTTON_UP,
s_touch.panX, s_touch.panY, SDL_BUTTON_RIGHT);
break;
case TouchState::TWO_PENDING:
case TouchState::PINCH:
break;
default:
break;
}
Expand Down Expand Up @@ -961,4 +1064,3 @@ AudioManager *SDL3GameEngine::createAudioManager(Bool dummy)
}

#endif // !_WIN32