Duke3D: Add projectile WORKSLIKE flag PROJECTILE_HITRADIUS_ADDITIVE

This flag alters the radiusdamage calculation such that the blast
damage is added to the current htextra of the actor, rather than
overwriting the current applied damage completely.

source/duke3d/src/actors.cpp

@@ -199,7 +199,11 @@ void A_RadiusDamageObject_Internal(int const spriteNum, int const otherSprite, i
             if (dmgBase == dmgFuzz)
                 ++dmgFuzz;
 
-            dmgActor.htextra = dmgBase + (krand()%(dmgFuzz-dmgBase));
+            int dmgTotal = dmgBase + (krand()%(dmgFuzz-dmgBase));
+            if (SpriteProjectile[spriteNum].workslike & PROJECTILE_HITRADIUS_ADDITIVE)
+                dmgActor.htextra += dmgTotal;
+            else
+                dmgActor.htextra = dmgTotal;
 
             if (!A_CheckSpriteFlags(otherSprite, SFLAG_NODAMAGEPUSH))
             {

source/duke3d/src/actors.h

@@ -388,6 +388,8 @@ enum pflags_t : unsigned int
     PROJECTILE_ACCURATE          = 0x00100000,
     PROJECTILE_NOSETOWNERSHADE   = 0x00200000,
     PROJECTILE_RPG_IMPACT_DAMAGE = 0x00400000,
+//    PROJECTILE_PENETRATE         = 0x00800000,
+    PROJECTILE_HITRADIUS_ADDITIVE  = 0x01000000,
     PROJECTILE_MOVED             = 0x80000000,  // internal flag, do not document
     PROJECTILE_TYPE_MASK         = PROJECTILE_HITSCAN | PROJECTILE_RPG | PROJECTILE_KNEE | PROJECTILE_BLOOD,
 };

source/duke3d/src/gamedef.cpp

@@ -6286,6 +6286,7 @@ static void C_AddDefaultDefinitions(void)
         { "PF_COOLEXPLOSION1",    PROJECTILE_COOLEXPLOSION1 },
         { "PF_EXPLODEONTIMER",    PROJECTILE_EXPLODEONTIMER },
         { "PF_FORCEIMPACT",       PROJECTILE_FORCEIMPACT },
+        { "PF_HITRADIUS_ADDITIVE", PROJECTILE_HITRADIUS_ADDITIVE },
         { "PF_HITSCAN",           PROJECTILE_HITSCAN },
         { "PF_KNEE",              PROJECTILE_KNEE },
         { "PF_LOSESVELOCITY",     PROJECTILE_LOSESVELOCITY },