- Fixed: Thing_ProjectileIntercept broke slightly when converted to the new

vector math routines (almost two years ago!) because the original code
  multiplied down columns of the rotation matrix, but the new code multiplies
  across rows of the matrix instead. This is remedied by flipping the matrix
  across the x=y axis by reversing the sign of the sine value passed to the
  matrix constructor.


SVN r1324 (trunk)

docs/rh-log.txt

@@ -1,3 +1,11 @@
+December 17, 2008
+- Fixed: Thing_ProjectileIntercept broke slightly when converted to the new
+  vector math routines (almost two years ago!) because the original code
+  multiplied down columns of the rotation matrix, but the new code multiplies
+  across rows of the matrix instead. This is remedied by flipping the matrix
+  across the x=y axis by reversing the sign of the sine value passed to the
+  matrix constructor.
+
 December 15, 2008
 - Fixed: Autoloading a game (e.g. respawning after dying in single player)
   during demo playback prematurely ended demo control of the player.

src/p_things.cpp

@@ -173,7 +173,7 @@ bool P_Thing_Move (int tid, AActor *source, int mapspot, bool fog)
 	return false;
 }
 
-bool P_Thing_Projectile (int tid, AActor *source, int type, const char * type_name, angle_t angle,
+bool P_Thing_Projectile (int tid, AActor *source, int type, const char *type_name, angle_t angle,
 	fixed_t speed, fixed_t vspeed, int dest, AActor *forcedest, int gravity, int newtid,
 	bool leadTarget)
 {
@@ -288,7 +288,7 @@ bool P_Thing_Projectile (int tid, AActor *source, int type, const char * type_na
 							double ydotx = -aim | tvel;
 							double a = acos (clamp (ydotx / targspeed / dist, -1.0, 1.0));
 							double multiplier = double(pr_leadtarget.Random2())*0.1/255+1.1;
-							double sinb = clamp (targspeed*multiplier * sin(a) / fspeed, -1.0, 1.0);
+							double sinb = -clamp (targspeed*multiplier * sin(a) / fspeed, -1.0, 1.0);
 
 							// Use the cross product of two of the triangle's sides to get a
 							// rotation vector.