account for add state (#6858)

Author: Kestrellius

code/weapon/weapons.cpp

@@ -8878,8 +8878,13 @@ void weapon_render(object* obj, model_draw_list *scene)
 			float offset_z_mult = wip->weapon_curves.get_output(weapon_info::WeaponCurveOutputs::LASER_OFFSET_Z_MULT, *wp, &wp->modular_curves_instance);
 			float switch_ang_mult = wip->weapon_curves.get_output(weapon_info::WeaponCurveOutputs::LASER_HEADON_SWITCH_ANG_MULT, *wp, &wp->modular_curves_instance);
 			float switch_rate_mult = wip->weapon_curves.get_output(weapon_info::WeaponCurveOutputs::LASER_HEADON_SWITCH_RATE_MULT, *wp, &wp->modular_curves_instance);
-			bool anim_has_curve = wip->weapon_curves.has_curve(weapon_info::WeaponCurveOutputs::LASER_ANIM_STATE);
-			float anim_state = wip->weapon_curves.get_output(weapon_info::WeaponCurveOutputs::LASER_ANIM_STATE, *wp, &wp->modular_curves_instance);
+			bool anim_has_curve = wip->weapon_curves.has_curve(weapon_info::WeaponCurveOutputs::LASER_ANIM_STATE) || wip->weapon_curves.has_curve(weapon_info::WeaponCurveOutputs::LASER_ANIM_STATE_ADD);
+			// We'll be using both anim_state and anim_state_add if either one has a curve defined, even if the other doesn't,
+			// so we need to make sure they've got sensible defaults, which in this case means 0.
+			float anim_state = 0.f;
+			if (wip->weapon_curves.has_curve(weapon_info::WeaponCurveOutputs::LASER_ANIM_STATE)) {
+				anim_state = wip->weapon_curves.get_output(weapon_info::WeaponCurveOutputs::LASER_ANIM_STATE, *wp, &wp->modular_curves_instance);
+			}
 			float anim_state_add = 0.f;
 			if (wip->weapon_curves.has_curve(weapon_info::WeaponCurveOutputs::LASER_ANIM_STATE_ADD)) {
 				anim_state_add = wip->weapon_curves.get_output(weapon_info::WeaponCurveOutputs::LASER_ANIM_STATE_ADD, *wp, &wp->modular_curves_instance);