INT 33h: Games like Lemmings do things with INT 33h that confuse the …

…auto-range detction code. Rather than make the code complicated and convoluted, add dosbox.conf options to manually specify ranges and other INT 33h adjustments.

CHANGELOG

@@ -1,4 +1,12 @@
 Next:
+  - INT 33 mouse emulation: Add dosbox.conf options to force a specific
+    coordinate system for the DOS game with respect to host/guest mouse
+    cursor integration (getting the DOS cursor to match the host cursor
+    within the window). Add dosbox.conf option where additional adjustments
+    are available. The maximum x/y and max-adjust options are ideal for
+    Lemmings 2, which uses INT 33h in a way that confuses the automatic
+    range detection code used to synchronize cursor position and therefore
+    needs this option, and the first Lemmings as well. (joncampbell123).
   - PIT timer: Fix restart_counter(), the delay computation was completely
     backwards. This is particularly important where it concerns programs
     that use the PIT to detect the rate at which the Pentium time stamp

src/dosbox.cpp

@@ -4564,6 +4564,22 @@ void DOSBOX_SetupConfigSections(void) {
     Pbool->Set_help("Enable INT 33H for mouse support.");
     Pbool->SetBasic(true);
 
+    Pint = secprop->Add_int("int33 max x", Property::Changeable::WhenIdle, 0);
+    Pint->Set_help("For guest to host cursor integration with DOS games, assume the maximum reported X coordinate has this value, if this is nonzero.\n"
+                   "Use this option if the automatic range detection fails to work correctly with the DOS game and the cursor doesn't match the host cursor position.\n"
+                   "- Lemmings 2: Use X=640 Y=400");
+
+    Pint = secprop->Add_int("int33 max y", Property::Changeable::WhenIdle, 0);
+    Pint->Set_help("For guest to host cursor integration with DOS games, assume the maximum reported Y coordinate has this value, if this is nonzero.\n"
+                   "Use this option if the automatic range detection fails to work correctly with the DOS game and the cursor doesn't match the host cursor position.\n"
+                   "- See the max X setting for a list of games");
+
+    Pstring = secprop->Add_string("int33 xy adjust",Property::Changeable::OnlyAtStart,"");
+    Pstring->Set_help("A list of adjustments to INT 33h position adjustments to help align the guest cursor to the host. name=value, comma separated\n"
+                      "x=spec, y=spec\n"
+                      "spec:   <number>    position adjust, can be positive or negative\n"
+                      "        max-excess  if game sets maximum larger than int33 max x/y, adjust the position forward by the difference");
+
     Pint = secprop->Add_int("mouse report rate",Property::Changeable::WhenIdle,0);
     Pint->Set_help("Mouse reporting rate, or 0 for auto. This affects how often mouse events are reported to the guest through the mouse interrupt.\n"
 		    "Some games including CyClone need a lower reporting rate to function correctly. Auto mode allows the guest to change the report rate through the PS/2 mouse emulation.\n"

src/ints/mouse.cpp

@@ -47,6 +47,10 @@
 # pragma warning(disable:4244) /* const fmath::local::uint64_t to double possible loss of data */
 #endif
 
+static bool adjust_x_max_excess = false,adjust_y_max_excess = false;
+static unsigned int assume_max_x = 0,assume_max_y = 0;
+static int adjust_x = 0,adjust_y = 0;
+
 #define VMWARE_PORT         0x5658u        // communication port
 #define VMWARE_PORTHB       0x5659u        // communication port, high bandwidth
 static Bitu PortRead(Bitu port, Bitu iolen);
@@ -895,6 +899,29 @@ void Mouse_CursorMoved(float xrel,float yrel,float x,float y,bool emulate) {
         mouse.x       = x1 * mouse.max_screen_x;
         mouse.y       = y1 * mouse.max_screen_y;
 
+	/* Cursor adjustment to help in-game cursor match host:
+	 *
+	 * x=[-]adjustment     i.e. x=5 or x=-8
+	 * y=[-]adjustment     i.e. y=8 or y=-10 */
+        mouse.x += adjust_x;
+        mouse.y += adjust_y;
+	/* When used with int33 max x/y:
+	 * max-excess can be specified to state that if the game set the maximum
+	 * past the dosbox.conf max value, that the x/y coordinates are adjusted
+	 * by the difference, for use with games that make use of the min/max
+	 * constraint per screen and offset the min/max by some offset (Lemmings 2).
+	 *
+	 * x=max-excess
+	 * y=max-excess */
+        if (adjust_x_max_excess) {
+            if (mouse.max_x > (int)assume_max_x)
+                mouse.x += (mouse.max_x - assume_max_x);
+        }
+        if (adjust_y_max_excess) {
+            if (mouse.max_y > (int)assume_max_y)
+                mouse.y += (mouse.max_y - assume_max_y);
+        }
+
         if (mouse.x < mouse.min_x)
             mouse.x = mouse.min_x;
         if (mouse.y < mouse.min_y)
@@ -1455,8 +1482,15 @@ void Mouse_AfterNewVideoMode(bool setmode) {
     mouse.cursorType = 0;
     mouse.enabled=true;
 
-    mouse.max_screen_x = mouse.max_x;
-    mouse.max_screen_y = mouse.max_y;
+    if (assume_max_x > 0)
+        mouse.max_screen_x = assume_max_x;
+    else
+        mouse.max_screen_x = mouse.max_x;
+
+    if (assume_max_y > 0)
+        mouse.max_screen_y = assume_max_y;
+    else
+        mouse.max_screen_y = mouse.max_y;
 }
 
 //Much too empty, Mouse_NewVideoMode contains stuff that should be in here
@@ -1650,7 +1684,7 @@ static Bitu INT33_Handler(void) {
              *      set after mode set is the only way to make sure mouse pointer integration
              *      tracks the guest pointer properly. */
             if (mouse.first_range_setx || mouse.buttons == 0) {
-                if (mouse.min_x == 0 && mouse.max_x > 0) {
+                if (mouse.min_x == 0 && mouse.max_x > 0 && assume_max_x == 0) {
                     // most games redefine the range so they can use a saner range matching the screen
                     int16_t nval = mouse.max_x;
 
@@ -1719,7 +1753,7 @@ static Bitu INT33_Handler(void) {
              *      set after mode set is the only way to make sure mouse pointer integration
              *      tracks the guest pointer properly. */
             if (mouse.first_range_sety || mouse.buttons == 0) {
-                if (mouse.min_y == 0 && mouse.max_y > 0) {
+                if (mouse.min_y == 0 && mouse.max_y > 0 && assume_max_y == 0) {
                     // most games redefine the range so they can use a saner range matching the screen
                     int16_t nval = mouse.max_y;
 
@@ -2316,6 +2350,49 @@ void MOUSE_Startup(Section *sec) {
     user_mouse_report_rate=section->Get_int("mouse report rate");
     UpdateMouseReportRate();
 
+    assume_max_x=section->Get_int("int33 max x");
+    assume_max_y=section->Get_int("int33 max y");
+
+    {
+        const char *s = section->Get_string("int33 xy adjust");
+        while (*s != 0) {
+            if (*s == ' ') {
+                s++;
+            }
+            else {
+                const char *base = s;
+                while (*s != 0 && *s != ',' && *s != '=') s++;
+                std::string name = std::string(base,(size_t)(s-base)),value;
+                if (*s == '=') {
+                    s++;
+                    base = s;
+                    while (*s != 0 && *s != ',') s++;
+                    value = std::string(base,(size_t)(s-base));
+                }
+                if (*s == ',') s++;
+
+                if (name == "x") {
+                    const char *v = value.c_str();
+                    if (isdigit(*v) || (*v == '-' && isdigit(v[1]))) {
+                        adjust_x = atoi(v);
+                    }
+                    else if (!strcmp(v,"max-excess")) {
+                        adjust_x_max_excess = true;
+                    }
+                }
+                else if (name == "y") {
+                    const char *v = value.c_str();
+                    if (isdigit(*v) || (*v == '-' && isdigit(v[1]))) {
+                        adjust_y = atoi(v);
+                    }
+                    else if (!strcmp(v,"max-excess")) {
+                        adjust_y_max_excess = true;
+                    }
+                }
+            }
+        }
+    }
+
     en_int33_hide_if_intsub=section->Get_bool("int33 hide host cursor if interrupt subroutine");
 
     en_int33_hide_if_polling=section->Get_bool("int33 hide host cursor when polling");