kc3-lang/SDL

diff --git a/include/SDL_hints.h b/include/SDL_hints.h
index 1462f4e..9aad2e3 100644
--- a/include/SDL_hints.h
+++ b/include/SDL_hints.h
@@ -173,7 +173,18 @@ extern "C" {
 #define SDL_HINT_GRAB_KEYBOARD              "SDL_GRAB_KEYBOARD"
 
 /**
- *  \brief Minimize your SDL_Window if it loses key focus when in Fullscreen mode. Defaults to true.
+*  \brief  A variable controlling whether relative mouse mode is implemented using mouse warping
+*
+*  This variable can be set to the following values:
+*    "0"       - Relative mouse mode uses raw input
+*    "1"       - Relative mouse mode uses mouse warping
+*
+*  By default SDL will use raw input for relative mouse mode
+*/
+#define SDL_HINT_MOUSE_RELATIVE_MODE_WARP    "SDL_MOUSE_RELATIVE_MODE_WARP"
+
+/**
+ *  \brief Minimize your SDL_Window if it loses key focus when in fullscreen mode. Defaults to true.
  *
  */
 #define SDL_HINT_VIDEO_MINIMIZE_ON_FOCUS_LOSS   "SDL_VIDEO_MINIMIZE_ON_FOCUS_LOSS"
diff --git a/src/events/SDL_mouse.c b/src/events/SDL_mouse.c
index 742802a..8eb4414 100644
--- a/src/events/SDL_mouse.c
+++ b/src/events/SDL_mouse.c
@@ -23,6 +23,7 @@
 /* General mouse handling code for SDL */
 
 #include "SDL_assert.h"
+#include "SDL_hints.h"
 #include "SDL_timer.h"
 #include "SDL_events.h"
 #include "SDL_events_c.h"
@@ -205,12 +206,24 @@ SDL_PrivateSendMouseMotion(SDL_Window * window, SDL_MouseID mouseID, int relativ
     int yrel;
     int x_max = 0, y_max = 0;
 
-    /* relative motion is calculated regarding the system cursor last position */
+    if (mouse->relative_mode_warp) {
+        int center_x = 0, center_y = 0;
+        SDL_GetWindowSize(window, &center_x, &center_y);
+        center_x /= 2;
+        center_y /= 2;
+        if (x == center_x && y == center_y) {
+            mouse->last_x = center_x;
+            mouse->last_y = center_y;
+            return 0;
+        }
+        SDL_WarpMouseInWindow(window, center_x, center_y);
+    }
+
     if (relative) {
         xrel = x;
         yrel = y;
-        x = (mouse->last_x + x);
-        y = (mouse->last_y + y);
+        x = (mouse->last_x + xrel);
+        y = (mouse->last_y + yrel);
     } else {
         xrel = x - mouse->last_x;
         yrel = y - mouse->last_y;
@@ -225,7 +238,7 @@ SDL_PrivateSendMouseMotion(SDL_Window * window, SDL_MouseID mouseID, int relativ
     }
 
     /* Update internal mouse coordinates */
-    if (mouse->relative_mode == SDL_FALSE) {
+    if (!mouse->relative_mode) {
         mouse->x = x;
         mouse->y = y;
     } else {
@@ -481,21 +494,36 @@ SDL_WarpMouseInWindow(SDL_Window * window, int x, int y)
     }
 }
 
+static SDL_bool
+ShouldUseRelativeModeWarp(SDL_Mouse *mouse)
+{
+    const char *hint;
+
+    if (!mouse->SetRelativeMouseMode) {
+        return SDL_TRUE;
+    }
+
+    hint = SDL_GetHint(SDL_HINT_MOUSE_RELATIVE_MODE_WARP);
+    if (hint) {
+        if (*hint == '0') {
+            return SDL_FALSE;
+        } else {
+            return SDL_TRUE;
+        }
+    }
+    return SDL_FALSE;
+}
+
 int
 SDL_SetRelativeMouseMode(SDL_bool enabled)
 {
     SDL_Mouse *mouse = SDL_GetMouse();
     SDL_Window *focusWindow = SDL_GetKeyboardFocus();
-    int original_x = mouse->x, original_y = mouse->y;
 
     if (enabled == mouse->relative_mode) {
         return 0;
     }
 
-    if (!mouse->SetRelativeMouseMode) {
-        return SDL_Unsupported();
-    }
-
     if (enabled && focusWindow) {
         /* Center it in the focused window to prevent clicks from going through
          * to background windows.
@@ -504,23 +532,26 @@ SDL_SetRelativeMouseMode(SDL_bool enabled)
         SDL_WarpMouseInWindow(focusWindow, focusWindow->w/2, focusWindow->h/2);
     }
 
-    if (mouse->SetRelativeMouseMode(enabled) < 0) {
+    /* Set the relative mode */
+    if (!enabled && mouse->relative_mode_warp) {
+        mouse->relative_mode_warp = SDL_FALSE;
+    } else if (enabled && ShouldUseRelativeModeWarp(mouse)) {
+        mouse->relative_mode_warp = SDL_TRUE;
+    } else if (mouse->SetRelativeMouseMode(enabled) < 0) {
         return -1;
     }
-
-    /* Set the relative mode */
     mouse->relative_mode = enabled;
 
-    if (enabled) {
-        /* Save the expected mouse position */
-        mouse->original_x = original_x;
-        mouse->original_y = original_y;
-    } else if (mouse->focus) {
-        /* Restore the expected mouse position */
-        SDL_WarpMouseInWindow(mouse->focus, mouse->original_x, mouse->original_y);
+    if (mouse->focus) {
+        SDL_UpdateWindowGrab(mouse->focus);
+
+        /* Put the cursor back to where the application expects it */
+        if (!enabled) {
+            SDL_WarpMouseInWindow(mouse->focus, mouse->x, mouse->y);
+        }
     }
 
-    /* Flush pending mouse motion */
+    /* Flush pending mouse motion - ideally we would pump events, but that's not always safe */
     SDL_FlushEvent(SDL_MOUSEMOTION);
 
     /* Update cursor visibility */
diff --git a/src/events/SDL_mouse_c.h b/src/events/SDL_mouse_c.h
index fd34c66..427b3b1 100644
--- a/src/events/SDL_mouse_c.h
+++ b/src/events/SDL_mouse_c.h
@@ -73,8 +73,7 @@ typedef struct
     int last_x, last_y;         /* the last reported x and y coordinates */
     Uint32 buttonstate;
     SDL_bool relative_mode;
-    /* the x and y coordinates when relative mode was activated */
-    int original_x, original_y;
+    SDL_bool relative_mode_warp;
 
     /* Data for double-click tracking */
     int num_clickstates;
diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
index 5aacac8..ff80891 100644
--- a/src/video/SDL_video.c
+++ b/src/video/SDL_video.c
@@ -2055,8 +2055,9 @@ SDL_UpdateWindowGrab(SDL_Window * window)
 {
     if (_this->SetWindowGrab) {
         SDL_bool grabbed;
-        if ((window->flags & SDL_WINDOW_INPUT_GRABBED) &&
-            (window->flags & SDL_WINDOW_INPUT_FOCUS)) {
+        if (SDL_GetMouse()->relative_mode_warp ||
+            ((window->flags & SDL_WINDOW_INPUT_GRABBED) &&
+             (window->flags & SDL_WINDOW_INPUT_FOCUS))) {
             grabbed = SDL_TRUE;
         } else {
             grabbed = SDL_FALSE;
diff --git a/src/video/windows/SDL_windowsevents.c b/src/video/windows/SDL_windowsevents.c
index 9e82dc9..a06f11f 100644
--- a/src/video/windows/SDL_windowsevents.c
+++ b/src/video/windows/SDL_windowsevents.c
@@ -290,6 +290,7 @@ static void
 WIN_UpdateClipCursor(SDL_Window *window)
 {
     SDL_WindowData *data = (SDL_WindowData *) window->driverdata;
+    SDL_Mouse *mouse = SDL_GetMouse();
 
     /* Don't clip the cursor while we're in the modal resize or move loop */
     if (data->in_modal_loop) {
@@ -297,7 +298,7 @@ WIN_UpdateClipCursor(SDL_Window *window)
         return;
     }
         
-    if (SDL_GetMouse()->relative_mode) {
+    if (mouse->relative_mode && !mouse->relative_mode_warp) {
         LONG cx, cy;
         RECT rect;
         GetWindowRect(data->hwnd, &rect);
@@ -312,8 +313,9 @@ WIN_UpdateClipCursor(SDL_Window *window)
         rect.bottom = cy+1;
 
         ClipCursor(&rect);
-    } else if ((window->flags & SDL_WINDOW_INPUT_GRABBED) &&
-               (window->flags & SDL_WINDOW_INPUT_FOCUS)) {
+    } else if (mouse->relative_mode_warp ||
+               ((window->flags & SDL_WINDOW_INPUT_GRABBED) &&
+                (window->flags & SDL_WINDOW_INPUT_FOCUS))) {
         RECT rect;
         if (GetClientRect(data->hwnd, &rect) && !IsRectEmpty(&rect)) {
             ClientToScreen(data->hwnd, (LPPOINT) & rect);
@@ -426,8 +428,12 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
         break;
 
     case WM_MOUSEMOVE:
-        if( !SDL_GetMouse()->relative_mode )
-            SDL_SendMouseMotion(data->window, 0, 0, GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));
+        {
+            SDL_Mouse *mouse = SDL_GetMouse();
+            if (!mouse->relative_mode || mouse->relative_mode_warp) {
+                SDL_SendMouseMotion(data->window, 0, 0, GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));
+            }
+        }
         /* don't break here, fall through to check the wParam like the button presses */
     case WM_LBUTTONUP:
     case WM_RBUTTONUP:
@@ -437,49 +443,50 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
     case WM_RBUTTONDOWN:
     case WM_MBUTTONDOWN:
     case WM_XBUTTONDOWN:
-        if( !SDL_GetMouse()->relative_mode )
-            WIN_CheckWParamMouseButtons( wParam, data );
+        {
+            SDL_Mouse *mouse = SDL_GetMouse();
+            if (!mouse->relative_mode || mouse->relative_mode_warp) {
+                WIN_CheckWParamMouseButtons(wParam, data);
+            }
+        }
         break;
 
     case WM_INPUT:
-    {
-        HRAWINPUT hRawInput = (HRAWINPUT)lParam;
-        RAWINPUT inp;
-        UINT size = sizeof(inp);
+        {
+            SDL_Mouse *mouse = SDL_GetMouse();
+            HRAWINPUT hRawInput = (HRAWINPUT)lParam;
+            RAWINPUT inp;
+            UINT size = sizeof(inp);
 
-        if(!SDL_GetMouse()->relative_mode)
-            break;
+            if (!mouse->relative_mode || mouse->relative_mode_warp) {
+                break;
+            }
 
-        GetRawInputData(hRawInput, RID_INPUT, &inp, &size, sizeof(RAWINPUTHEADER));
+            GetRawInputData(hRawInput, RID_INPUT, &inp, &size, sizeof(RAWINPUTHEADER));
 
-        /* Mouse data */
-        if(inp.header.dwType == RIM_TYPEMOUSE)
-        {
-            RAWMOUSE* mouse = &inp.data.mouse;
+            /* Mouse data */
+            if (inp.header.dwType == RIM_TYPEMOUSE) {
+                RAWMOUSE* mouse = &inp.data.mouse;
+
+                if ((mouse->usFlags & 0x01) == MOUSE_MOVE_RELATIVE) {
+                    SDL_SendMouseMotion(data->window, 0, 1, (int)mouse->lLastX, (int)mouse->lLastY);
+                } else {
+                    /* synthesize relative moves from the abs position */
+                    static SDL_Point initialMousePoint;
+                    if (initialMousePoint.x == 0 && initialMousePoint.y == 0) {
+                        initialMousePoint.x = mouse->lLastX;
+                        initialMousePoint.y = mouse->lLastY;
+                    }
+
+                    SDL_SendMouseMotion(data->window, 0, 1, (int)(mouse->lLastX-initialMousePoint.x), (int)(mouse->lLastY-initialMousePoint.y) );
 
-            if((mouse->usFlags & 0x01) == MOUSE_MOVE_RELATIVE)
-            {
-                SDL_SendMouseMotion(data->window, 0, 1, (int)mouse->lLastX, (int)mouse->lLastY);
-            }
-            else
-            {
-                /* synthesize relative moves from the abs position */
-                static SDL_Point initialMousePoint;
-                if ( initialMousePoint.x == 0 && initialMousePoint.y == 0 )
-                {
                     initialMousePoint.x = mouse->lLastX;
                     initialMousePoint.y = mouse->lLastY;
                 }
-
-                SDL_SendMouseMotion(data->window, 0, 1, (int)(mouse->lLastX-initialMousePoint.x), (int)(mouse->lLastY-initialMousePoint.y) );
-
-                initialMousePoint.x = mouse->lLastX;
-                initialMousePoint.y = mouse->lLastY;
+                WIN_CheckRawMouseButtons( mouse->usButtonFlags, data );
             }
-            WIN_CheckRawMouseButtons( mouse->usButtonFlags, data );
         }
         break;
-    }
 
     case WM_MOUSEWHEEL:
         {
@@ -497,8 +504,8 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
                     s_AccumulatedMotion += WHEEL_DELTA;
                 }
             }
-            break;
         }
+        break;
 
     case WM_MOUSEHWHEEL:
         {
@@ -516,8 +523,8 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
                     s_AccumulatedMotion += WHEEL_DELTA;
                 }
             }
-            break;
         }
+        break;
 
 #ifdef WM_MOUSELEAVE
     case WM_MOUSELEAVE:
@@ -549,8 +556,8 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 
             GetKeyboardState(keyboardState);
             if (ToUnicode(wParam, (lParam >> 16) & 0xff, keyboardState, (LPWSTR)&utf32, 1, 0) > 0) {
-                WORD repitition;
-                for (repitition = lParam & 0xffff; repitition > 0; repitition--) {
+                WORD repetition;
+                for (repetition = lParam & 0xffff; repetition > 0; repetition--) {
                     WIN_ConvertUTF32toUTF8(utf32, text);
                     SDL_SendKeyboardText(text);
                 }
diff --git a/src/video/x11/SDL_x11events.c b/src/video/x11/SDL_x11events.c
index 423bd87..44ca1cd 100644
--- a/src/video/x11/SDL_x11events.c
+++ b/src/video/x11/SDL_x11events.c
@@ -698,7 +698,7 @@ X11_DispatchEvent(_THIS)
 
     case MotionNotify:{
             SDL_Mouse *mouse = SDL_GetMouse();
-            if(!mouse->relative_mode) {
+            if(!mouse->relative_mode || mouse->relative_mode_warp) {
 #ifdef DEBUG_MOTION
                 printf("window %p: X11 motion: %d,%d\n", xevent.xmotion.x, xevent.xmotion.y);
 #endif
diff --git a/src/video/x11/SDL_x11xinput2.c b/src/video/x11/SDL_x11xinput2.c
index 196dd2a..8993561 100644
--- a/src/video/x11/SDL_x11xinput2.c
+++ b/src/video/x11/SDL_x11xinput2.c
@@ -134,7 +134,7 @@ X11_HandleXinput2Event(SDL_VideoData *videodata,XGenericEventCookie *cookie)
             SDL_Mouse *mouse = SDL_GetMouse();
             double relative_cords[2];
 
-            if (!mouse->relative_mode) {
+            if (!mouse->relative_mode || mouse->relative_mode_warp) {
                 return 0;
             }