Add hack abstraction to make mouse IDs sequential

SDL3 (and therefore sdl2-compat) changed mouse IDs from being seuqential
(so they could be used as an index) to effectively random. We have to
hack over an abstraction for this ourselves to make it work.

Lol!

fixes nzp-team/nzportable#1131

Author: Peter0x44

engine/client/in_sdl.c

@@ -1172,6 +1172,28 @@ void INS_SetOSK(int osk)
 {
 }
 #endif
+
+// SDL2 gives IDs from zero, but SDL3 does not
+// sdl2-compat also doesn't make any attempt to revert this behavior, so we have to do it ourselves
+static uint32_t internal__mice[16];
+static int internal__mice_count=0;
+
+int INS_MouseID(uint32_t mid)
+{
+	for (int i = 0; i < internal__mice_count; ++i)
+	{
+		if (internal__mice[i] == mid)
+			return i;
+	}
+	if (internal__mice_count < 16)
+	{
+		internal__mice[internal__mice_count] = mid;
+		return internal__mice_count++;
+	}
+	return -1;
+}
+
+
 void Sys_SendKeyEvents(void)
 {
 	SDL_Event event;
@@ -1207,6 +1229,7 @@ void Sys_SendKeyEvents(void)
 #endif
 #endif
 // NZP end
+	int which;
 
 	while(SDL_PollEvent(&event))
 	{
@@ -1352,26 +1375,28 @@ void Sys_SendKeyEvents(void)
 #if SDL_MAJOR_VERSION >= 2
 			if (event.motion.which == SDL_TOUCH_MOUSEID)
 				break;	//ignore legacy touch events.
+			which = INS_MouseID(event.motion.which);
 #endif
 			if (!mouseactive)
-				IN_MouseMove(event.motion.which, true, event.motion.x, event.motion.y, 0, 0);
+				IN_MouseMove(which, true, event.motion.x, event.motion.y, 0, 0);
 			else
-				IN_MouseMove(event.motion.which, false, event.motion.xrel, event.motion.yrel, 0, 0);
+				IN_MouseMove(which, false, event.motion.xrel, event.motion.yrel, 0, 0);
 			break;
 
 #if SDL_MAJOR_VERSION >= 2
 		case SDL_MOUSEWHEEL:
+			which = INS_MouseID(event.wheel.which);
 			if (event.wheel.direction == SDL_MOUSEWHEEL_FLIPPED)
 				event.wheel.y *= -1;
 			for (; event.wheel.y > 0; event.wheel.y--)
 			{
-				IN_KeyEvent(event.button.which, true, K_MWHEELUP, 0);
-				IN_KeyEvent(event.button.which, false, K_MWHEELUP, 0);
+				IN_KeyEvent(which, true, K_MWHEELUP, 0);
+				IN_KeyEvent(which, false, K_MWHEELUP, 0);
 			}
 			for (; event.wheel.y < 0; event.wheel.y++)
 			{
-				IN_KeyEvent(event.button.which, true, K_MWHEELDOWN, 0);
-				IN_KeyEvent(event.button.which, false, K_MWHEELDOWN, 0);
+				IN_KeyEvent(which, true, K_MWHEELDOWN, 0);
+				IN_KeyEvent(which, false, K_MWHEELDOWN, 0);
 			}
 /*			for (; event.wheel.x > 0; event.wheel.x--)
 			{
@@ -1392,10 +1417,11 @@ void Sys_SendKeyEvents(void)
 			if (event.button.which == SDL_TOUCH_MOUSEID)
 				break;	//ignore legacy touch events. SDL_FINGER* events above will handle it (for multitouch)
 #endif
+			which = INS_MouseID(event.button.which);
 			//Hmm. SDL allows for 255 buttons, but only defines 5...
 			if (event.button.button > sizeof(tbl_sdltoquakemouse)/sizeof(tbl_sdltoquakemouse[0]))
 				event.button.button = sizeof(tbl_sdltoquakemouse)/sizeof(tbl_sdltoquakemouse[0]);
-			IN_KeyEvent(event.button.which, event.button.state, tbl_sdltoquakemouse[event.button.button-1], 0);
+			IN_KeyEvent(which, event.button.state, tbl_sdltoquakemouse[event.button.button-1], 0);
 			break;
 
 #if SDL_MAJOR_VERSION >= 2