WIP for SAGA engine.

 o text formatting is not consistent with rules, just indent utility is too
   dumb for that
 o it does not use OSystem, i.e. it runs on direct SDL calls
 o it may not even compile on your box
 o if you enable it, expect zillions of warnings
 o no sound

Now it runs ITE intro as reinherit did

svn-id: r13564

1 files changed, 83 insertions, 0 deletions

diff --git a/saga/transitions.cpp b/saga/transitions.cpp
new file mode 100644
index 0000000000..759652593d
--- /dev/null
+++ b/saga/transitions.cpp
@@ -0,0 +1,83 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2004 The ScummVM project
+ *
+ * The ReInherit Engine is (C)2000-2003 by Daniel Balsom.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * $Header$
+ *
+ */
+/*
+ Description:	
+ 
+	Background transition routines
+
+ Notes: 
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "yslib.h"
+
+#include "reinherit.h"
+
+namespace Saga {
+
+int
+TRANSITION_Dissolve(uchar * dst_img,
+    int dst_w,
+    int dst_h,
+    int dst_p, const uchar * src_img, int src_p, int flags, double percent)
+{
+#define XOR_MASK 0xB400;
+
+	int pixelcount = dst_w * dst_h;
+	int seqlimit = (int)(65535 * percent);
+
+	int seq = 1;
+	int i;
+
+	YS_IGNORE_PARAM(flags);
+	YS_IGNORE_PARAM(src_p);
+	YS_IGNORE_PARAM(dst_p);
+
+	for (i = 0; i < seqlimit; i++) {
+
+		if (seq & 1) {
+			seq = (seq >> 1) ^ XOR_MASK;
+		} else {
+			seq = seq >> 1;
+		}
+
+		if (seq == 1) {
+			return 0;
+		}
+
+		if (seq >= pixelcount) {
+			continue;
+		} else {
+
+			dst_img[seq] = src_img[seq];
+
+		}
+	}
+
+	return 1;
+}
+
+} // End of namespace Saga
+