Gameplay|All Games: Compatibility option for pushable momentum

When pushing objects with the MF2_PUSHABLE flag, the previous (vanillla?) behavior is that the pushed objects may accumulate unlimited amounts of momentum. The new compatibility cvar “game-objects-pushable-limit” (default 1) causes the pushed objects’ momentum to not exceed the speed of the object doing the pushing. This makes the behavior more physically accurate.
skyjake · Dec 2, 2018 · e581e99 · e581e99
1 parent b6969b4
commit e581e99
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Showing 5 changed files with 37 additions and 4 deletions.
diff --git a/doomsday/apps/plugins/common/include/config.h b/doomsday/apps/plugins/common/include/config.h
@@ -54,6 +54,7 @@ typedef struct libcommon_config_s {
     // Gameplay:
     byte            switchSoundOrigin;
     byte            defaultRuleFastMonsters;
+    byte            pushableMomentumLimitedToPusher;
 
     // Weapons:
     byte            weaponCycleSequential; // if true multiple next/prev weapon impulses can be chained to allow the user to "count-click-switch".

diff --git a/doomsday/apps/plugins/common/src/common.cpp b/doomsday/apps/plugins/common/src/common.cpp
@@ -115,4 +115,5 @@ void Common_Register()
 #ifdef __JDOOM__
     C_VAR_BYTE2("game-monsters-fast",   &cfg.common.defaultRuleFastMonsters, 0, 0, 1, fastMonstersChanged);
 #endif
+    C_VAR_BYTE ("game-objects-pushable-limit", &cfg.common.pushableMomentumLimitedToPusher, 0, 0, 1);
 }
diff --git a/doomsday/apps/plugins/common/src/game/g_game.cpp b/doomsday/apps/plugins/common/src/game/g_game.cpp
@@ -314,6 +314,7 @@ void G_CommonPreInit()
     ::quitInProgress = false;
 
     // Apply the default game rules.
+    cfg.common.pushableMomentumLimitedToPusher = true;
     gfw_Session()->applyNewRules(gfw_DefaultGameRules() = GameRules());
 
     // Register hooks.

diff --git a/doomsday/apps/plugins/common/src/hu_menu.cpp b/doomsday/apps/plugins/common/src/hu_menu.cpp
@@ -1150,6 +1150,14 @@ void Hu_MenuInitGameplayOptionsPage()
             .setGroup(1)
             .setShortcut('w');
 
+    page->addWidget(new LabelWidget("Pushable Speed Limit"))
+            .setLeft()
+            .setGroup(1);
+    page->addWidget(new CVarToggleWidget("game-objects-pushable-limit"))
+            .setRight()
+            .setGroup(1)
+            .setShortcut('p');
+
 # if __JDOOM__ || __JDOOM64__
 
     page->addWidget(new LabelWidget("Zombie Players Can\n   Exit Maps")).setLeft()

diff --git a/doomsday/apps/plugins/common/src/world/p_map.cpp b/doomsday/apps/plugins/common/src/world/p_map.cpp
@@ -850,10 +850,32 @@ static int PIT_CheckThing(mobj_t *thing, void * /*context*/)
 
     if((thing->flags2 & MF2_PUSHABLE) && !(tmThing->flags2 & MF2_CANNOTPUSH))
     {
-        // Push thing
-        thing->mom[MX] += tmThing->mom[MX] / 4;
-        thing->mom[MY] += tmThing->mom[MY] / 4;
-        NetSv_PlayerMobjImpulse(thing, tmThing->mom[MX]/4, tmThing->mom[MY]/4, 0);
+        // Push thing.
+        coord_t pushImpulse[2] = {tmThing->mom[MX] / 4, tmThing->mom[MY] / 4};
+
+        for (int axis = 0; axis < 2; ++axis)
+        {
+            // Do not exceed the momentum of the thing doing the pushing.
+            if (cfg.common.pushableMomentumLimitedToPusher)
+            {
+                coord_t maxIncrement = tmThing->mom[axis] - thing->mom[axis];
+                if (thing->mom[axis] > 0 && pushImpulse[axis] > 0)
+                {
+                    pushImpulse[axis] = de::max(0.0, de::min(pushImpulse[axis], maxIncrement));
+                }
+                else if (thing->mom[axis] < 0 && pushImpulse[axis] < 0)
+                {
+                    pushImpulse[axis] = de::min(0.0, de::max(pushImpulse[axis], maxIncrement));
+                }
+            }
+
+            thing->mom[axis] += pushImpulse[axis];
+        }
+
+        if (!de::fequal(pushImpulse[MX], 0) || !de::fequal(pushImpulse[MY], 0))
+        {
+            NetSv_PlayerMobjImpulse(thing, float(pushImpulse[MX]), float(pushImpulse[MY]), 0);
+        }
     }
 
     // @fixme Kludge: Always treat blood as a solid.