From 157d79f2d6bf459c3918bf92f811741e10c3ec6c Mon Sep 17 00:00:00 2001
From: Scott Duensing <scott@duensing.com>
Date: Thu, 19 Mar 2026 14:19:41 -0500
Subject: [PATCH] Fixed mouse bounding on real hardware.  INI is now written
 with DOS line endings, not UNIX.

---
 dvx/platform/dvxPlatformDos.c | 95 ++++++++++++++++++++++-------------
 dvxshell/Makefile             |  2 +-
 2 files changed, 61 insertions(+), 36 deletions(-)

diff --git a/dvx/platform/dvxPlatformDos.c b/dvx/platform/dvxPlatformDos.c
index 58ec7d4..3d291c8 100644
--- a/dvx/platform/dvxPlatformDos.c
+++ b/dvx/platform/dvxPlatformDos.c
@@ -68,6 +68,17 @@ static void     sysInfoAppend(const char *fmt, ...);
 static bool    sHasMouseWheel  = false;
 static int32_t sLastWheelDelta = 0;
 
+// Software cursor tracking.  Many real-hardware mouse drivers fail to
+// honour INT 33h functions 07h/08h (set coordinate range) in VESA modes
+// because they don't recognise non-standard video modes.  We bypass the
+// driver's position entirely: platformMousePoll reads raw mickey deltas
+// via function 0Bh, accumulates them into sCurX/sCurY, and clamps to
+// the screen bounds.  Function 03h is still used for button state.
+static int32_t sMouseRangeW = 0;
+static int32_t sMouseRangeH = 0;
+static int32_t sCurX        = 0;
+static int32_t sCurY        = 0;
+
 // Alt+key scan code to ASCII lookup table (indexed by BIOS scan code).
 // INT 16h returns these scan codes with ascii=0 for Alt+key combos.
 // Using a 256-byte lookup table instead of a switch or if-chain because
@@ -1122,30 +1133,20 @@ bool platformKeyboardRead(PlatformKeyEventT *evt) {
 void platformMouseInit(int32_t screenW, int32_t screenH) {
     __dpmi_regs r;
 
+    sMouseRangeW = screenW;
+    sMouseRangeH = screenH;
+    sCurX        = screenW / 2;
+    sCurY        = screenH / 2;
+
     // Function 00h: reset driver, detect mouse hardware
     memset(&r, 0, sizeof(r));
     r.x.ax = 0x0000;
     __dpmi_int(0x33, &r);
 
-    // Function 07h: set horizontal min/max range
+    // Flush any stale mickey counters so the first poll starts clean.
+    // Function 0Bh returns and resets the accumulated motion counters.
     memset(&r, 0, sizeof(r));
-    r.x.ax = 0x0007;
-    r.x.cx = 0;
-    r.x.dx = screenW - 1;
-    __dpmi_int(0x33, &r);
-
-    // Function 08h: set vertical min/max range
-    memset(&r, 0, sizeof(r));
-    r.x.ax = 0x0008;
-    r.x.cx = 0;
-    r.x.dx = screenH - 1;
-    __dpmi_int(0x33, &r);
-
-    // Function 04h: warp cursor to center of screen
-    memset(&r, 0, sizeof(r));
-    r.x.ax = 0x0004;
-    r.x.cx = screenW / 2;
-    r.x.dx = screenH / 2;
+    r.x.ax = 0x000B;
     __dpmi_int(0x33, &r);
 }
 
@@ -1173,32 +1174,55 @@ void platformMouseSetAccel(int32_t threshold) {
 // platformMousePoll
 // ============================================================
 //
-// Reads current mouse state via INT 33h function 03h.
-// Returns: CX=X position, DX=Y position, BX=button state
-// (bit 0 = left, bit 1 = right, bit 2 = middle).
-//
-// Polling is used instead of a callback/event model because the
-// DVX event loop already runs at frame rate. Installing a real-mode
-// callback for mouse events would add DPMI mode-switch overhead
-// on every mickeyed movement, which is wasteful when we only sample
-// once per frame anyway.
+// Reads button state via function 03h and raw mickey deltas via
+// function 0Bh.  Position is tracked in software (sCurX/sCurY)
+// rather than using the driver's coordinates, because many real-
+// hardware mouse drivers cannot handle VESA mode coordinate ranges.
+// Function 0Bh returns the accumulated mickey motion since the last
+// call and is reliable across all drivers.
 
 void platformMousePoll(int32_t *mx, int32_t *my, int32_t *buttons) {
     __dpmi_regs r;
 
+    // Function 03h: read button state only
     memset(&r, 0, sizeof(r));
     r.x.ax = 0x0003;
     __dpmi_int(0x33, &r);
 
-    *mx      = r.x.cx;
-    *my      = r.x.dx;
-    *buttons = r.x.bx & 0x07;  // BL only: bits 0-2 = left/right/middle
+    *buttons = r.x.bx & 0x07;
 
     // BH = signed 8-bit wheel counter (cleared on read by the driver).
-    // Only meaningful if the wheel API was activated via platformMouseWheelInit.
     if (sHasMouseWheel) {
         sLastWheelDelta = (int32_t)(int8_t)(r.x.bx >> 8);
     }
+
+    // Function 0Bh: read mickey motion counters (signed 16-bit deltas,
+    // cleared on read).  Accumulate into software cursor position.
+    memset(&r, 0, sizeof(r));
+    r.x.ax = 0x000B;
+    __dpmi_int(0x33, &r);
+
+    sCurX += (int16_t)r.x.cx;
+    sCurY += (int16_t)r.x.dx;
+
+    if (sCurX < 0) {
+        sCurX = 0;
+    }
+
+    if (sCurX >= sMouseRangeW) {
+        sCurX = sMouseRangeW - 1;
+    }
+
+    if (sCurY < 0) {
+        sCurY = 0;
+    }
+
+    if (sCurY >= sMouseRangeH) {
+        sCurY = sMouseRangeH - 1;
+    }
+
+    *mx = sCurX;
+    *my = sCurY;
 }
 
 
@@ -1247,12 +1271,13 @@ int32_t platformMouseWheelPoll(void) {
 // so the pointer visually sticks to the border.
 
 void platformMouseWarp(int32_t x, int32_t y) {
-    __dpmi_regs r;
+    sCurX = x;
+    sCurY = y;
 
+    // Flush any pending mickeys so the next poll doesn't undo the warp
+    __dpmi_regs r;
     memset(&r, 0, sizeof(r));
-    r.x.ax = 0x0004;
-    r.x.cx = x;
-    r.x.dx = y;
+    r.x.ax = 0x000B;
     __dpmi_int(0x33, &r);
 }
 
diff --git a/dvxshell/Makefile b/dvxshell/Makefile
index e0e2c05..d055ce1 100644
--- a/dvxshell/Makefile
+++ b/dvxshell/Makefile
@@ -32,7 +32,7 @@ $(TARGET): $(OBJS) $(LIBDIR)/libdvx.a $(LIBDIR)/libtasks.a | $(BINDIR)
 	rm -f $(BINDIR)/dvx
 
 $(CONFIGDIR)/dvx.ini: ../dvx.ini | $(CONFIGDIR)
-	cp $< $@
+	sed 's/$$/\r/' $< > $@
 
 $(OBJDIR)/%.o: %.c | $(OBJDIR)
 	$(CC) $(CFLAGS) -c -o $@ $<