SCI: Fixed path finding in Amiga SCI1 games

Added wrapper functions to read/write from dynmem segments, as these are
treated as BE in Amiga versions (as we treat them like raw data instead
of reg_t's), whereas the rest are LE. Thanks to waltervn and wjp for their
help on this

3 files changed, 26 insertions, 6 deletions

diff --git a/engines/sci/engine/kpathing.cpp b/engines/sci/engine/kpathing.cpp
index cb70cf91e0..c98d93c2d9 100644
--- a/engines/sci/engine/kpathing.cpp
+++ b/engines/sci/engine/kpathing.cpp
@@ -264,9 +264,9 @@ struct PathfindingState {
 static Common::Point readPoint(SegmentRef list_r, int offset) {
 	Common::Point point;
 
-	if (list_r.isRaw) {
-		point.x = (int16)READ_LE_UINT16(list_r.raw + offset * POLY_POINT_SIZE);
-		point.y = (int16)READ_LE_UINT16(list_r.raw + offset * POLY_POINT_SIZE + 2);
+	if (list_r.isRaw) {	// dynmem blocks are raw
+		point.x = (int16)READ_SCI1ENDIAN_UINT16(list_r.raw + offset * POLY_POINT_SIZE);
+		point.y = (int16)READ_SCI1ENDIAN_UINT16(list_r.raw + offset * POLY_POINT_SIZE + 2);
 	} else {
 		point.x = list_r.reg[offset * 2].toUint16();
 		point.y = list_r.reg[offset * 2 + 1].toUint16();
@@ -275,9 +275,9 @@ static Common::Point readPoint(SegmentRef list_r, int offset) {
 }
 
 static void writePoint(SegmentRef ref, int offset, const Common::Point &point) {
-	if (ref.isRaw) {
-		WRITE_LE_UINT16(ref.raw + offset * POLY_POINT_SIZE, point.x);
-		WRITE_LE_UINT16(ref.raw + offset * POLY_POINT_SIZE + 2, point.y);
+	if (ref.isRaw) {	// dynmem blocks are raw
+		WRITE_SCI1ENDIAN_UINT16(ref.raw + offset * POLY_POINT_SIZE, point.x);
+		WRITE_SCI1ENDIAN_UINT16(ref.raw + offset * POLY_POINT_SIZE + 2, point.y);
 	} else {
 		ref.reg[offset * 2] = make_reg(0, point.x);
 		ref.reg[offset * 2 + 1] = make_reg(0, point.y);
diff --git a/engines/sci/util.cpp b/engines/sci/util.cpp
index f6a2465682..6bc08e6b63 100644
--- a/engines/sci/util.cpp
+++ b/engines/sci/util.cpp
@@ -30,6 +30,20 @@
 
 namespace Sci {
 
+uint16 READ_SCI1ENDIAN_UINT16(const void *ptr) {
+	if (g_sci->getPlatform() == Common::kPlatformAmiga && getSciVersion() >= SCI_VERSION_1_EGA_ONLY && getSciVersion() <= SCI_VERSION_1_LATE)
+		return READ_BE_UINT16(ptr);
+
+	return READ_LE_UINT16(ptr);
+}
+
+void WRITE_SCI1ENDIAN_UINT16(void *ptr, uint16 val) {
+	if (g_sci->getPlatform() == Common::kPlatformAmiga && getSciVersion() >= SCI_VERSION_1_EGA_ONLY && getSciVersion() <= SCI_VERSION_1_LATE)
+		WRITE_BE_UINT16(ptr, val);
+
+	WRITE_LE_UINT16(ptr, val);
+}
+
 uint16 READ_SCI11ENDIAN_UINT16(const void *ptr) {
 	if (g_sci->getPlatform() == Common::kPlatformMacintosh && getSciVersion() >= SCI_VERSION_1_1)
 		return READ_BE_UINT16(ptr);
diff --git a/engines/sci/util.h b/engines/sci/util.h
index d9ced5c9f6..d1f1c2ffa9 100644
--- a/engines/sci/util.h
+++ b/engines/sci/util.h
@@ -30,6 +30,12 @@
 
 namespace Sci {
 
+// Wrappers for reading/writing integer values for SCI1 Amiga.
+// Amiga versions store big endian data in dynmem blocks, as
+// the game resources are in LE, but the actual system is BE.
+uint16 READ_SCI1ENDIAN_UINT16(const void *ptr);
+void WRITE_SCI1ENDIAN_UINT16(void *ptr, uint16 val);
+
 // Wrappers for reading integer values for SCI1.1+.
 // Mac versions have big endian data for some fields.
 uint16 READ_SCI11ENDIAN_UINT16(const void *ptr);