Attempt to take care of the Negative values in LPRECT error

[Lionel Ulmer <lionel.ulmer@free.fr>]

Hi all,

It seems that DDraw does clipping against the surface when negative (or out
of bounds) values are sent as any source or destination rectangles. Support
this in the 'standard' case (ie when no stretching is done).

Changelog:
 Support negative values in RECTs during Blts

             Lionel (who did a CVS update this time :-) )

-- 
		 Lionel Ulmer - http://www.bbrox.org/
Index: dlls/ddraw/dsurface/dib.c
===================================================================
RCS file: /home/wine/wine/dlls/ddraw/dsurface/dib.c,v
retrieving revision 1.14
diff -u -r1.14 dib.c
--- dlls/ddraw/dsurface/dib.c	2 Aug 2002 19:10:16 -0000	1.14
+++ dlls/ddraw/dsurface/dib.c	3 Aug 2002 17:41:34 -0000
@@ -374,13 +374,6 @@
     }
 
     if (rdst) {
-	if ((rdst->top < 0) ||
-	    (rdst->left < 0) ||
-	    (rdst->bottom < 0) ||
-	    (rdst->right < 0)) {
-	  ERR(" Negative values in LPRECT !!!\n");
-	  goto release;
-	}
 	memcpy(&xdst,rdst,sizeof(xdst));
     } else {
 	xdst.top	= 0;
@@ -390,13 +383,6 @@
     }
 
     if (rsrc) {
-	if ((rsrc->top < 0) ||
-	    (rsrc->left < 0) ||
-	    (rsrc->bottom < 0) ||
-	    (rsrc->right < 0)) {
-	  ERR(" Negative values in LPRECT !!!\n");
-	  goto release;
-	}
 	memcpy(&xsrc,rsrc,sizeof(xsrc));
     } else {
 	if (src) {
@@ -408,9 +394,63 @@
 	    memset(&xsrc,0,sizeof(xsrc));
 	}
     }
+
     if (src) assert((xsrc.bottom-xsrc.top) <= sdesc.dwHeight);
     assert((xdst.bottom-xdst.top) <= ddesc.dwHeight);
+    
+    /* Now handle negative values in the rectangles. Warning: only supported for now
+       in the 'simple' cases (ie not in any stretching / rotation cases).
+
+       First, the case where nothing is to be done.
+    */
+    if (((xdst.bottom <= 0) || (xdst.right <= 0) || (xdst.top >= (int) ddesc.dwHeight) || (xdst.left >= (int) ddesc.dwWidth)) ||
+        ((src != NULL) &&
+         ((xsrc.bottom <= 0) || (xsrc.right <= 0) || (xsrc.top >= (int) sdesc.dwHeight) || (xsrc.left >= (int) sdesc.dwWidth))))
+    {
+        TRACE("Nothing to be done !\n");
+        goto release;
+    }
+
+    /* The easy case : the source-less blits.... */
+    if (src == NULL) {
+        RECT full_rect = { 0, 0, ddesc.dwHeight, ddesc.dwWidth };
+        RECT temp_rect; /* No idea if intersect rect can be the same as one of the source rect */
+        IntersectRect(&temp_rect, &full_rect, &xdst);
+        xdst = temp_rect;
+    } else {
+        /* This is trickier as any update to one rectangle need to be propagated to the other */
+        int clip_horiz = (xdst.left < 0) || (xdst.right  > (int) ddesc.dwWidth ) || (xsrc.left < 0) || (xsrc.right  > (int) sdesc.dwWidth );
+        int clip_vert  = (xdst.top  < 0) || (xdst.bottom > (int) ddesc.dwHeight) || (xsrc.top  < 0) || (xsrc.bottom > (int) sdesc.dwHeight);
+        if (clip_vert || clip_horiz) {
+            /* Now check if this is a special case or not... */
+            if ((((xdst.bottom - xdst.top ) != (xsrc.bottom - xsrc.top )) && clip_vert ) ||
+                (((xdst.right  - xdst.left) != (xsrc.right  - xsrc.left)) && clip_horiz) ||
+                (dwFlags & DDBLT_DDFX)) {
+                WARN("Out of screen rectangle in special case. Not handled right now.\n");
+                goto release;
+            }
 
+            if (clip_horiz) {
+              if (xsrc.left < 0) { xdst.left -= xsrc.left; xsrc.left = 0; }
+              if (xdst.left < 0) { xsrc.left -= xdst.left; xdst.left = 0; }
+              if (xsrc.right > sdesc.dwWidth) { xdst.right -= (xsrc.right - (int) sdesc.dwWidth); xsrc.right = (int) sdesc.dwWidth; }
+              if (xdst.right > ddesc.dwWidth) { xsrc.right -= (xdst.right - (int) ddesc.dwWidth); xdst.right = (int) ddesc.dwWidth; }
+            }
+            if (clip_vert) {
+                if (xsrc.top < 0) { xdst.top -= xsrc.top; xsrc.top = 0; }
+                if (xdst.top < 0) { xsrc.top -= xdst.top; xdst.top = 0; }
+                if (xsrc.bottom > sdesc.dwHeight) { xdst.bottom -= (xsrc.bottom - (int) sdesc.dwHeight); xsrc.bottom = (int) sdesc.dwHeight; }
+                if (xdst.bottom > ddesc.dwHeight) { xsrc.bottom -= (xdst.bottom - (int) ddesc.dwHeight); xdst.bottom = (int) ddesc.dwHeight; }
+            }
+            /* And check if after clipping something is still to be done... */
+            if ((xdst.bottom <= 0) || (xdst.right <= 0) || (xdst.top >= (int) ddesc.dwHeight) || (xdst.left >= (int) ddesc.dwWidth) ||
+                (xsrc.bottom <= 0) || (xsrc.right <= 0) || (xsrc.top >= (int) sdesc.dwHeight) || (xsrc.left >= (int) sdesc.dwWidth)) {
+                TRACE("Nothing to be done after clipping !\n");
+                goto release;
+            }
+        }
+    }
+    
     bpp = GET_BPP(ddesc);
     srcheight = xsrc.bottom - xsrc.top;
     srcwidth = xsrc.right - xsrc.left;