Initialize floor->type and floor->crush fields in EV_BuildStairs()

The floor->type and floor->crush fields of the floor thinkers added in
EV_BuildStairs() were originally left uninitialized and thus contained
random memory content.

Initialize them to make sure the floor->type field does not trigger
propagation of random content into the special and texture fields of
the adjacent sector in T_MoveFloor(). That is, make sure its value
is neither donutRaise, i.e. 11, nor lowerAndChange, i.e. 6.

Also, the chances of 32 bit of random memory being "true", i.e. 0, are
negligible.

This is functionally equivalent to what PrBoom+ is doing.

Fixes desync of mm09-512.lmp.

Fixes #368.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/doom/p_floor.c b/src/doom/p_floor.c
index 1384ee6b..c120d616 100644
--- a/src/doom/p_floor.c
+++ b/src/doom/p_floor.c
@@ -493,6 +493,9 @@ EV_BuildStairs
 	floor->speed = speed;
 	height = sec->floorheight + stairsize;
 	floor->floordestheight = height;
+	// Initialize
+	floor->type = lowerFloor;
+	floor->crush = true;
 		
 	texture = sec->floorpic;
 	
@@ -536,6 +539,9 @@ EV_BuildStairs
 		floor->sector = sec;
 		floor->speed = speed;
 		floor->floordestheight = height;
+		// Initialize
+		floor->type = lowerFloor;
+		floor->crush = true;
 		ok = 1;
 		break;
 	    }