cp_airfight.cpp

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/*
Copyright (C) 2002-2023 UFO: Alien Invasion.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

#include "../../DateTime.h"
#include "../../cl_shared.h"
#include "cp_campaign.h"
#include "cp_mapfightequip.h"
#include "cp_geoscape.h"
#include "cp_ufo.h"
#include "cp_missions.h"
#include "save/save_airfight.h"
#include "../../sound/s_main.h"

#define AIRCRAFT_INVALID -1

static void AIRFIGHT_RemoveProjectile (aircraftProjectile_t* projectile)
{
    const ptrdiff_t num = (ptrdiff_t)(projectile - ccs.projectiles);
    REMOVE_ELEM_ADJUST_IDX(ccs.projectiles, num, ccs.numProjectiles);
}

static bool AIRFIGHT_AddProjectile (const base_t* attackingBase, const installation_t* attackingInstallation, aircraft_t* attacker, aircraft_t* target, aircraftSlot_t* weaponSlot)
{
    aircraftProjectile_t* projectile;

    if (ccs.numProjectiles >= MAX_PROJECTILESONGEOSCAPE) {
        cgi->Com_DPrintf(DEBUG_CLIENT, "Too many projectiles on map\n");
        return false;
    }

    projectile = &ccs.projectiles[ccs.numProjectiles];

    if (!weaponSlot->ammo) {
        cgi->Com_Printf("AIRFIGHT_AddProjectile: Error - no ammo assigned\n");
        return false;
    }

    assert(weaponSlot->item);

    projectile->aircraftItem = weaponSlot->ammo;
    if (attackingBase) {
        projectile->attackingAircraft = nullptr;
        VectorSet(projectile->pos[0], attackingBase->pos[0], attackingBase->pos[1], 0);
        VectorSet(projectile->attackerPos, attackingBase->pos[0], attackingBase->pos[1], 0);
    } else if (attackingInstallation) {
        projectile->attackingAircraft = nullptr;
        VectorSet(projectile->pos[0], attackingInstallation->pos[0], attackingInstallation->pos[1], 0);
        VectorSet(projectile->attackerPos, attackingInstallation->pos[0], attackingInstallation->pos[1], 0);
    } else {
        assert(attacker);
        projectile->attackingAircraft = attacker;
        VectorSet(projectile->pos[0], attacker->pos[0], attacker->pos[1], 0);
        /* attacker may move, use attackingAircraft->pos */
        VectorSet(projectile->attackerPos, 0, 0, 0);
    }

    projectile->numProjectiles++;

    assert(target);
    projectile->aimedAircraft = target;
    VectorSet(projectile->idleTarget, 0, 0, 0);

    projectile->time = 0;
    projectile->angle = 0.0f;

    projectile->bullets = weaponSlot->item->craftitem.bullets;
    projectile->beam = weaponSlot->item->craftitem.beam;
    projectile->rocket = !projectile->bullets && !projectile->beam;

    weaponSlot->ammoLeft--;
    if (weaponSlot->ammoLeft <= 0)
        AII_ReloadWeapon(weaponSlot);

    ccs.numProjectiles++;

    const char* sound;
    if (projectile->bullets) {
        sound = "geoscape/combat-gun";
    } else if (projectile->beam) {
        sound = "geoscape/combat-airlaser";
    } else if (projectile->rocket) {
        sound = "geoscape/combat-rocket";
    } else {
        sound = nullptr;
    }

    if (sound != nullptr)
        cgi->S_StartLocalSample(sound, 1.0f);

    return true;
}

#ifdef DEBUG

static void AIRFIGHT_ProjectileList_f (void)
{
    for (int i = 0; i < ccs.numProjectiles; i++) {
        cgi->Com_Printf("%i. (idx: %i)\n", i, ccs.projectiles[i].idx);
        cgi->Com_Printf("... type '%s'\n", ccs.projectiles[i].aircraftItem->id);
        if (ccs.projectiles[i].attackingAircraft)
            cgi->Com_Printf("... shooting aircraft '%s'\n", ccs.projectiles[i].attackingAircraft->id);
        else
            cgi->Com_Printf("... base is shooting, or shooting aircraft is destroyed\n");
        if (ccs.projectiles[i].aimedAircraft)
            cgi->Com_Printf("... aiming aircraft '%s'\n", ccs.projectiles[i].aimedAircraft->id);
        else
            cgi->Com_Printf("... aiming idle target at (%.02f, %.02f)\n",
                ccs.projectiles[i].idleTarget[0], ccs.projectiles[i].idleTarget[1]);
    }
}
#endif

static void AIRFIGHT_MissTarget (aircraftProjectile_t* projectile)
{
    vec3_t newTarget;
    float offset;

    assert(projectile);

    if (projectile->aimedAircraft) {
        VectorCopy(projectile->aimedAircraft->pos, newTarget);
        projectile->aimedAircraft = nullptr;
    } else {
        VectorCopy(projectile->idleTarget, newTarget);
    }

    /* get the distance between the projectile and target */
    const float distance = GetDistanceOnGlobe(projectile->pos[0], newTarget);

    /* Work out how much the projectile should miss the target by.  We dont want it too close
     * or too far from the original target.
     * * 1/3 distance between target and projectile * random (range -0.5 to 0.5)
     * * Then make sure the value is at least greater than 0.1 or less than -0.1 so that
     *   the projectile doesn't land too close to the target. */
    offset = (distance / 3) * (frand() - 0.5f);

    if (abs(offset) < 0.1f)
        offset = 0.1f;

    newTarget[0] = newTarget[0] + offset;
    newTarget[1] = newTarget[1] + offset;

    VectorCopy(newTarget, projectile->idleTarget);
}

int AIRFIGHT_CheckWeapon (const aircraftSlot_t* slot, float distance)
{
    assert(slot);

    /* check if there is a functional weapon in this slot */
    if (!slot->item || slot->installationTime != 0)
        return AIRFIGHT_WEAPON_CAN_NEVER_SHOOT;

    /* check if there is still ammo in this weapon */
    if (!slot->ammo || (slot->ammoLeft <= 0))
        return AIRFIGHT_WEAPON_CAN_NEVER_SHOOT;

    /* check if the target is within range of this weapon */
    if (distance > slot->ammo->craftitem.stats[AIR_STATS_WRANGE])
        return AIRFIGHT_WEAPON_CAN_NOT_SHOOT_AT_THE_MOMENT;

    /* check if weapon is reloaded */
    if (slot->delayNextShot > 0)
        return AIRFIGHT_WEAPON_CAN_NOT_SHOOT_AT_THE_MOMENT;

    return AIRFIGHT_WEAPON_CAN_SHOOT;
}

int AIRFIGHT_ChooseWeapon (const aircraftSlot_t* slot, int maxSlot, const vec2_t pos, const vec2_t targetPos)
{
    int slotIdx = AIRFIGHT_WEAPON_CAN_NEVER_SHOOT;
    float distance0 = 99999.9f;
    const float distance = GetDistanceOnGlobe(pos, targetPos);

    /* We choose the usable weapon with the smallest range */
    for (int i = 0; i < maxSlot; i++) {
        const int weaponStatus = AIRFIGHT_CheckWeapon(slot + i, distance);

        /* set slotIdx to AIRFIGHT_WEAPON_CAN_NOT_SHOOT_AT_THE_MOMENT if needed */
        /* this will only happen if weapon_state is AIRFIGHT_WEAPON_CAN_NOT_SHOOT_AT_THE_MOMENT
         * and no weapon has been found that can shoot. */
        if (weaponStatus > slotIdx)
            slotIdx = AIRFIGHT_WEAPON_CAN_NOT_SHOOT_AT_THE_MOMENT;

        /* select this weapon if this is the one with the shortest range */
        if (weaponStatus >= AIRFIGHT_WEAPON_CAN_SHOOT && distance < distance0) {
            slotIdx = i;
            distance0 = distance;
        }
    }
    return slotIdx;
}

static float AIRFIGHT_ProbabilityToHit (const aircraft_t* shooter, const aircraft_t* target, const aircraftSlot_t* slot)
{
    float probability = 0.0f;

    if (!slot->item) {
        cgi->Com_Printf("AIRFIGHT_ProbabilityToHit: no weapon assigned to attacking aircraft\n");
        return probability;
    }

    if (!slot->ammo) {
        cgi->Com_Printf("AIRFIGHT_ProbabilityToHit: no ammo in weapon of attacking aircraft\n");
        return probability;
    }

    /* Take Base probability from the ammo of the attacking aircraft */
    probability = slot->ammo->craftitem.stats[AIR_STATS_ACCURACY];
    cgi->Com_DPrintf(DEBUG_CLIENT, "AIRFIGHT_ProbabilityToHit: Base probability: %f\n", probability);

    /* Modify this probability by items of the attacking aircraft (stats is in percent) */
    if (shooter)
        probability *= shooter->stats[AIR_STATS_ACCURACY] / 100.0f;

    cgi->Com_DPrintf(DEBUG_CLIENT, "AIRFIGHT_ProbabilityToHit: Probability after accounting items of attacker: %f\n", probability);

    /* Modify this probability by items of the aimed aircraft (stats is in percent) */
    if (target)
        probability /= target->stats[AIR_STATS_ECM] / 100.0f;

    cgi->Com_DPrintf(DEBUG_CLIENT, "AIRFIGHT_ProbabilityToHit: Probability after accounting ECM of target: %f\n", probability);

    /* If shooter is a PHALANX craft, check the targeting skills of the pilot */
    if (shooter && !AIR_IsUFO(shooter)) {
        if (shooter->pilot) {
            probability += ( ( ( 1.4f - ( shooter->pilot->chr.score.skills[SKILL_TARGETING] / 100.0f ) ) * ( shooter->pilot->chr.score.skills[SKILL_TARGETING] / 100.0f ) ) - 0.2f );

            cgi->Com_DPrintf(DEBUG_CLIENT, "AIRFIGHT_ProbabilityToHit: Probability after accounting targeting skill of shooter: %f\n",
                    probability);
        }
    }

    /* If target is a PHALANX craft, check the evading skills of the pilot */
    if (target && !AIR_IsUFO(target)) {
        if (target->pilot) {
            probability -= ( ( ( 1.4f - ( target->pilot->chr.score.skills[SKILL_EVADING] / 100.0f ) ) * ( target->pilot->chr.score.skills[SKILL_EVADING] / 100.0f ) ) - 0.2f );

            cgi->Com_DPrintf(DEBUG_CLIENT, "AIRFIGHT_ProbabilityToHit: Probability after accounting evasion skill of target: %f\n",
                    probability);
        }
    }

    /* Probability should not exceed 0.95 so there is always a chance to miss */
    probability = std::min(probability, 0.95f);

    cgi->Com_DPrintf(DEBUG_CLIENT, "AIRFIGHT_ProbabilityToHit: Probability to hit: %f\n", probability);

    return probability;
}

void AIRFIGHT_ExecuteActions (const campaign_t* campaign, aircraft_t* shooter, aircraft_t* target)
{
    /* some asserts */
    assert(shooter);
    assert(target);

    /* Check if the attacking aircraft can shoot */
    const int slotIdx = AIRFIGHT_ChooseWeapon(shooter->weapons, shooter->maxWeapons, shooter->pos, target->pos);

    /* if weapon found that can shoot */
    if (slotIdx >= AIRFIGHT_WEAPON_CAN_SHOOT) {
        aircraftSlot_t* weaponSlot = &shooter->weapons[slotIdx];
        const objDef_t* ammo = weaponSlot->ammo;

        /* shoot */
        if (AIRFIGHT_AddProjectile(nullptr, nullptr, shooter, target, weaponSlot)) {
            /* will we miss the target ? */
            const float probability = frand();
            cgi->Com_DPrintf(DEBUG_CLIENT, "AIRFIGHT_ExecuteActions: %s - Random probability to hit: %f\n", shooter->name, probability);
            weaponSlot->delayNextShot = ammo->craftitem.weaponDelay;

            const float calculatedProbability = AIRFIGHT_ProbabilityToHit(shooter, target, shooter->weapons + slotIdx);
            cgi->Com_DPrintf(DEBUG_CLIENT, "AIRFIGHT_ExecuteActions: %s - Calculated probability to hit: %f\n", shooter->name, calculatedProbability);

            if (probability > calculatedProbability)
                AIRFIGHT_MissTarget(&ccs.projectiles[ccs.numProjectiles - 1]);

            if (!AIR_IsUFO(shooter)) {
                /* Maybe UFO is going to shoot back ? */
                UFO_CheckShootBack(campaign, target, shooter);
            } else {
                /* an undetected UFO within radar range and firing should become detected */
                if (!shooter->detected && RADAR_CheckRadarSensored(shooter->pos)) {
                    /* stop time and notify */
                    MSO_CheckAddNewMessage(NT_UFO_ATTACKING, _("Notice"), va(_("A UFO is shooting at %s"), target->name));
                    RADAR_AddDetectedUFOToEveryRadar(shooter);
                    UFO_DetectNewUFO(shooter);
                }
            }
        }
    } else if (slotIdx == AIRFIGHT_WEAPON_CAN_NOT_SHOOT_AT_THE_MOMENT) {
        /* no ammo to fire atm (too far or reloading), pursue target */
        if (AIR_IsUFO(shooter)) {
            UFO_SendPursuingAircraft(shooter, target);
        } else
            AIR_SendAircraftPursuingUFO(shooter, target);
    } else {
        /* no ammo left, or no weapon, proceed with mission */
        if (AIR_IsUFO(shooter)) {
            shooter->aircraftTarget = nullptr;      /* reset target */
            CP_UFOProceedMission(campaign, shooter);
        } else {
            MS_AddNewMessage(_("Notice"), _("Our aircraft has no more ammo left - returning to home base now."));
            AIR_AircraftReturnToBase(shooter);
        }
    }
}

void AIRFIGHT_RemoveProjectileAimingAircraft (const aircraft_t* aircraft)
{
    aircraftProjectile_t* projectile;
    int idx = 0;

    if (!aircraft)
        return;

    for (projectile = ccs.projectiles; idx < ccs.numProjectiles; projectile++, idx++) {
        if (projectile->aimedAircraft != aircraft)
            continue;

        AIRFIGHT_MissTarget(projectile);
        if (projectile->attackingAircraft && projectile->attackingAircraft->homebase) {
            assert(!AIR_IsUFO(projectile->attackingAircraft));
            AIR_AircraftReturnToBase(projectile->attackingAircraft);
        }
    }
}

static void AIRFIGHT_UpdateProjectileForDestroyedAircraft (const aircraft_t* aircraft)
{
    aircraftProjectile_t* projectile;
    int idx;

    for (idx = 0, projectile = ccs.projectiles; idx < ccs.numProjectiles; projectile++, idx++) {
        const aircraft_t* attacker = projectile->attackingAircraft;

        if (attacker == aircraft)
            projectile->attackingAircraft = nullptr;
    }
}

void AIRFIGHT_ActionsAfterAirfight (const campaign_t* campaign, aircraft_t* shooter, aircraft_t* aircraft, bool phalanxWon)
{
    if (phalanxWon) {
        const byte* color;

        assert(aircraft);

        /* change destination of other projectiles aiming aircraft */
        AIRFIGHT_RemoveProjectileAimingAircraft(aircraft);
        /* now update the projectile for the destroyed aircraft, too */
        AIRFIGHT_UpdateProjectileForDestroyedAircraft(aircraft);

        /* don't remove ufo from global array: the mission is not over yet
         * UFO are removed from game only at the end of the mission
         * (in case we need to know what item to collect e.g.) */

        /* get the color value of the map at the crash position */
        color = GEO_GetColor(aircraft->pos, MAPTYPE_TERRAIN, nullptr);
        /* if this color value is not the value for water ...
         * and we hit the probability to spawn a crashsite mission */
        if (!MapIsWater(color)) {
            CP_SpawnCrashSiteMission(aircraft);
        } else {
            cgi->Com_DPrintf(DEBUG_CLIENT, "AIRFIGHT_ActionsAfterAirfight: zone: %s (%i:%i:%i)\n", cgi->csi->terrainDefs.getTerrainName(color), color[0], color[1], color[2]);
            MS_AddNewMessage(_("Interception"), _("UFO interception successful -- UFO lost to sea."));
            CP_MissionIsOverByUFO(aircraft);
        }

        /* skill increase (for aircraft only, base defences skip) */
        if (shooter) {
            /* Increase targeting skill of pilot who destroyed UFO. Never more than 70, see AIRFIGHT_ProbabilityToHit() */
            shooter->pilot->chr.score.skills[SKILL_TARGETING] += 1;
            shooter->pilot->chr.score.skills[SKILL_TARGETING] = std::min(shooter->pilot->chr.score.skills[SKILL_TARGETING], 70);

            /* Increase evasion skill of pilot who destroyed UFO if the aircraft it attacked can carry weapons.
             * Never more than 70, see AIRFIGHT_ProbabilityToHit() */
            if (aircraft->maxWeapons > 0) {
                shooter->pilot->chr.score.skills[SKILL_EVADING] += 1;
                shooter->pilot->chr.score.skills[SKILL_EVADING] = std::min(shooter->pilot->chr.score.skills[SKILL_EVADING], 70);
            }
        }
    } else {
        /* change destination of other projectiles aiming aircraft */
        AIRFIGHT_RemoveProjectileAimingAircraft(aircraft);

        /* and now update the projectile pointers (there still might be some in the air
         * of the current destroyed aircraft) - this is needed not send the aircraft
         * back to base as soon as the projectiles will hit their target */
        AIRFIGHT_UpdateProjectileForDestroyedAircraft(aircraft);

        /* notify UFOs that a phalanx aircraft has been destroyed */
        UFO_NotifyPhalanxAircraftRemoved(aircraft);

        if (!MapIsWater(GEO_GetColor(aircraft->pos, MAPTYPE_TERRAIN, nullptr))) {
            CP_SpawnRescueMission(aircraft, shooter);
        } else {
            /* Destroy the aircraft and everything onboard - the aircraft pointer
             * is no longer valid after this point */
            bool pilotSurvived = false;
            if (AIR_PilotSurvivedCrash(aircraft))
                pilotSurvived = true;

            AIR_DestroyAircraft(aircraft, pilotSurvived);

            if (pilotSurvived)
                MS_AddNewMessage(_("Interception"), _("Pilot ejected from craft"), MSG_STANDARD);
            else
                MS_AddNewMessage(_("Interception"), _("Pilot killed in action"), MSG_STANDARD);
        }

        /* Make UFO proceed with its mission, if it has not been already destroyed */
        if (shooter)
            CP_UFOProceedMission(campaign, shooter);

        MS_AddNewMessage(_("Interception"), _("A PHALANX craft has been destroyed"), MSG_DEATH);
    }
}

static bool AIRFIGHT_ProjectileReachedTarget (const aircraftProjectile_t* projectile, float movement)
{
    float distance;

    if (!projectile->aimedAircraft)
        /* the target is idle, its position is in idleTarget*/
        distance = GetDistanceOnGlobe(projectile->idleTarget, projectile->pos[0]);
    else {
        /* the target is moving, pointer to the other aircraft is aimedAircraft */
        distance = GetDistanceOnGlobe(projectile->aimedAircraft->pos, projectile->pos[0]);
    }

    /* projectile reaches its target */
    if (distance < movement)
        return true;

    assert(projectile->aircraftItem);

    /* check if the projectile went farther than it's range */
    distance = (float) projectile->time * projectile->aircraftItem->craftitem.weaponSpeed / (float)DateTime::SECONDS_PER_HOUR;
    if (distance > projectile->aircraftItem->craftitem.stats[AIR_STATS_WRANGE])
        return true;

    return false;
}

static int AIRFIGHT_GetDamage (const objDef_t* od, const aircraft_t* target)
{
    int damage;

    assert(od);

    /* already destroyed - do nothing */
    if (target->damage <= 0)
        return 0;

    /* base damage is given by the ammo */
    damage = od->craftitem.weaponDamage;

    /* reduce damages with shield target */
    damage -= target->stats[AIR_STATS_SHIELD];

    return damage;
}

static void AIRFIGHT_ProjectileHits (const campaign_t* campaign, aircraftProjectile_t* projectile)
{
    aircraft_t* target;

    assert(projectile);
    target = projectile->aimedAircraft;
    assert(target);

    /* if the aircraft is not on geoscape anymore, do nothing (returned to base) */
    if (AIR_IsAircraftInBase(target))
        return;

    const int damage = AIRFIGHT_GetDamage(projectile->aircraftItem, target);

    /* apply resulting damages - but only if damage > 0 - because the target might
     * already be destroyed, and we don't want to execute the actions after airfight
     * for every projectile */
    if (damage > 0) {
        assert(target->damage > 0);
        target->damage -= damage;
        if (target->damage <= 0) {
            /* Target is destroyed */
            AIRFIGHT_ActionsAfterAirfight(campaign, projectile->attackingAircraft, target, AIR_IsUFO(target));
            cgi->S_StartLocalSample("geoscape/combat-explosion", 1.0f);
        } else {
            if (projectile->rocket)
                cgi->S_StartLocalSample("geoscape/combat-rocket-exp", 1.0f);
        }
    }
}

static void AIRFIGHT_GetNextPointInPathFromVector (const float* movement, const vec2_t originalPoint, const vec3_t orthogonalVector, vec2_t finalPoint)
{
    vec3_t startPoint, finalVectorPoint;

    PolarToVec(originalPoint, startPoint);
    RotatePointAroundVector(finalVectorPoint, orthogonalVector, startPoint, *movement);
    VecToPolar(finalVectorPoint, finalPoint);
}

static void AIRFIGHT_GetNextPointInPath (const float* movement, const vec2_t originalPoint, const vec2_t targetPoint, float* angle, vec2_t finalPoint, vec3_t orthogonalVector)
{
    *angle = GEO_AngleOfPath(originalPoint, targetPoint, nullptr, orthogonalVector);
    AIRFIGHT_GetNextPointInPathFromVector(movement, originalPoint, orthogonalVector, finalPoint);
}

void AIRFIGHT_CampaignRunProjectiles (const campaign_t* campaign, int dt)
{
    int idx;

    /* ccs.numProjectiles is changed in AIRFIGHT_RemoveProjectile */
    for (idx = ccs.numProjectiles - 1; idx >= 0; idx--) {
        aircraftProjectile_t* projectile = &ccs.projectiles[idx];
        const float movement = (float) dt * projectile->aircraftItem->craftitem.weaponSpeed / (float)DateTime::SECONDS_PER_HOUR;
        projectile->time += dt;
        projectile->hasMoved = true;
        projectile->numInterpolationPoints = 0;

        /* Check if the projectile reached its destination (aircraft or idle point) */
        if (AIRFIGHT_ProjectileReachedTarget(projectile, movement)) {
            /* check if it got the ennemy */
            if (projectile->aimedAircraft)
                AIRFIGHT_ProjectileHits(campaign, projectile);

            /* remove the missile from ccs.projectiles[] */
            AIRFIGHT_RemoveProjectile(projectile);
        } else {
            float angle;
            vec3_t ortogonalVector, finalPoint, projectedPoint;

            /* missile is moving towards its target */
            if (projectile->aimedAircraft) {
                AIRFIGHT_GetNextPointInPath(&movement, projectile->pos[0], projectile->aimedAircraft->pos, &angle, finalPoint, ortogonalVector);
                AIRFIGHT_GetNextPointInPath(&movement, finalPoint, projectile->aimedAircraft->pos, &angle, projectedPoint, ortogonalVector);
            } else {
                AIRFIGHT_GetNextPointInPath(&movement, projectile->pos[0], projectile->idleTarget, &angle, finalPoint, ortogonalVector);
                AIRFIGHT_GetNextPointInPath(&movement, finalPoint, projectile->idleTarget, &angle, projectedPoint, ortogonalVector);
            }

            /* update angle of the projectile */
            projectile->angle = angle;
            VectorCopy(finalPoint, projectile->pos[0]);
            VectorCopy(projectedPoint, projectile->projectedPos[0]);
        }
    }
}

static void AIRFIGHT_BaseShoot (const base_t* base, baseWeapon_t* weapons, int maxWeapons)
{
    for (int i = 0; i < maxWeapons; i++) {
        aircraft_t* target = weapons[i].target;
        aircraftSlot_t* slot = &(weapons[i].slot);
        /* if no target, can't shoot */
        if (!target)
            continue;

        /* If the weapon is not ready in base, can't shoot. */
        if (slot->installationTime > 0)
            continue;

        /* if weapon is reloading, can't shoot */
        if (slot->delayNextShot > 0)
            continue;

        /* check that the ufo is still visible */
        if (!UFO_IsUFOSeenOnGeoscape(target)) {
            weapons[i].target = nullptr;
            continue;
        }

        /* Check if we can still fire on this target. */
        const float distance = GetDistanceOnGlobe(base->pos, target->pos);
        const int test = AIRFIGHT_CheckWeapon(slot, distance);
        /* weapon unable to shoot, reset target */
        if (test == AIRFIGHT_WEAPON_CAN_NEVER_SHOOT) {
            weapons[i].target = nullptr;
            continue;
        }
        /* we can't shoot with this weapon atm, wait to see if UFO comes closer */
        else if (test == AIRFIGHT_WEAPON_CAN_NOT_SHOOT_AT_THE_MOMENT)
            continue;
        /* target is too far, wait to see if UFO comes closer */
        else if (distance > slot->ammo->craftitem.stats[AIR_STATS_WRANGE])
            continue;

        /* shoot */
        if (AIRFIGHT_AddProjectile(base, nullptr, nullptr, target, slot)) {
            slot->delayNextShot = slot->ammo->craftitem.weaponDelay;
            /* will we miss the target ? */
            if (frand() > AIRFIGHT_ProbabilityToHit(nullptr, target, slot))
                AIRFIGHT_MissTarget(&ccs.projectiles[ccs.numProjectiles - 1]);
        }
    }
}

static void AIRFIGHT_InstallationShoot (const installation_t* installation, baseWeapon_t* weapons, int maxWeapons)
{
    for (int i = 0; i < maxWeapons; i++) {
        aircraft_t* target = weapons[i].target;
        aircraftSlot_t* slot = &(weapons[i].slot);
        /* if no target, can't shoot */
        if (!target)
            continue;

        /* If the weapon is not ready in base, can't shoot. */
        if (slot->installationTime > 0)
            continue;

        /* if weapon is reloading, can't shoot */
        if (slot->delayNextShot > 0)
            continue;

        /* check that the ufo is still visible */
        if (!UFO_IsUFOSeenOnGeoscape(target)) {
            weapons[i].target = nullptr;
            continue;
        }

        /* Check if we can still fire on this target. */
        const float distance = GetDistanceOnGlobe(installation->pos, target->pos);
        const int test = AIRFIGHT_CheckWeapon(slot, distance);
        /* weapon unable to shoot, reset target */
        if (test == AIRFIGHT_WEAPON_CAN_NEVER_SHOOT) {
            weapons[i].target = nullptr;
            continue;
        }
        /* we can't shoot with this weapon atm, wait to see if UFO comes closer */
        else if (test == AIRFIGHT_WEAPON_CAN_NOT_SHOOT_AT_THE_MOMENT)
            continue;
        /* target is too far, wait to see if UFO comes closer */
        else if (distance > slot->ammo->craftitem.stats[AIR_STATS_WRANGE])
            continue;

        /* shoot */
        if (AIRFIGHT_AddProjectile(nullptr, installation, nullptr, target, slot)) {
            slot->delayNextShot = slot->ammo->craftitem.weaponDelay;
            /* will we miss the target ? */
            if (frand() > AIRFIGHT_ProbabilityToHit(nullptr, target, slot))
                AIRFIGHT_MissTarget(&ccs.projectiles[ccs.numProjectiles - 1]);
        }
    }
}

void AIRFIGHT_CampaignRunBaseDefence (int dt)
{
    base_t* base;

    base = nullptr;
    while ((base = B_GetNext(base)) != nullptr) {
        int idx;

        if (B_IsUnderAttack(base))
            continue;

        for (idx = 0; idx < base->numBatteries; idx++) {
            baseWeapon_t* battery = &base->batteries[idx];
            aircraftSlot_t* slot = &battery->slot;
            if (slot->delayNextShot > 0)
                slot->delayNextShot -= dt;
            if (slot->ammoLeft <= 0)
                AII_ReloadWeapon(slot);
        }

        for (idx = 0; idx < base->numLasers; idx++) {
            baseWeapon_t* battery = &base->lasers[idx];
            aircraftSlot_t* slot = &battery->slot;
            if (slot->delayNextShot > 0)
                slot->delayNextShot -= dt;
            if (slot->ammoLeft <= 0)
                AII_ReloadWeapon(slot);
        }

        if (AII_BaseCanShoot(base)) {
            if (B_GetBuildingStatus(base, B_DEFENCE_MISSILE))
                AIRFIGHT_BaseShoot(base, base->batteries, base->numBatteries);
            if (B_GetBuildingStatus(base, B_DEFENCE_LASER))
                AIRFIGHT_BaseShoot(base, base->lasers, base->numLasers);
        }
    }

    INS_Foreach(installation) {
        if (installation->installationStatus != INSTALLATION_WORKING)
            continue;

        if (installation->installationTemplate->maxBatteries <= 0)
            continue;

        for (int idx = 0; idx < installation->installationTemplate->maxBatteries; idx++) {
            baseWeapon_t* battery = &installation->batteries[idx];
            aircraftSlot_t* slot = &battery->slot;
            if (slot->delayNextShot > 0)
                slot->delayNextShot -= dt;
            if (slot->ammoLeft <= 0)
                AII_ReloadWeapon(slot);
        }

        if (AII_InstallationCanShoot(installation)) {
            AIRFIGHT_InstallationShoot(installation, installation->batteries, installation->installationTemplate->maxBatteries);
        }
    }
}

bool AIRFIGHT_SaveXML (xmlNode_t* parent)
{
    for (int i = 0; i < ccs.numProjectiles; i++) {
        aircraftProjectile_t* projectile = &ccs.projectiles[i];
        xmlNode_t* node = cgi->XML_AddNode(parent, SAVE_AIRFIGHT_PROJECTILE);

        cgi->XML_AddString(node, SAVE_AIRFIGHT_ITEMID, projectile->aircraftItem->id);
        for (int j = 0; j < projectile->numProjectiles; j++)
            cgi->XML_AddPos2(node, SAVE_AIRFIGHT_POS, projectile->pos[j]);
        cgi->XML_AddPos3(node, SAVE_AIRFIGHT_IDLETARGET, projectile->idleTarget);

        cgi->XML_AddInt(node, SAVE_AIRFIGHT_TIME, projectile->time);
        cgi->XML_AddFloat(node, SAVE_AIRFIGHT_ANGLE, projectile->angle);
        cgi->XML_AddBoolValue(node, SAVE_AIRFIGHT_BULLET, projectile->bullets);
        cgi->XML_AddBoolValue(node, SAVE_AIRFIGHT_BEAM, projectile->beam);

        if (projectile->attackingAircraft) {
            xmlNode_t* attacking =  cgi->XML_AddNode(node, SAVE_AIRFIGHT_ATTACKINGAIRCRAFT);

            cgi->XML_AddBoolValue(attacking, SAVE_AIRFIGHT_ISUFO, AIR_IsUFO(projectile->attackingAircraft));
            if (AIR_IsUFO(projectile->attackingAircraft))
                cgi->XML_AddInt(attacking, SAVE_AIRFIGHT_AIRCRAFTIDX, UFO_GetGeoscapeIDX(projectile->attackingAircraft));
            else
                cgi->XML_AddInt(attacking, SAVE_AIRFIGHT_AIRCRAFTIDX, projectile->attackingAircraft->idx);
        }
        cgi->XML_AddPos3(node, SAVE_AIRFIGHT_ATTACKERPOS, projectile->attackerPos);

        if (projectile->aimedAircraft) {
            xmlNode_t* aimed =  cgi->XML_AddNode(node, SAVE_AIRFIGHT_AIMEDAIRCRAFT);

            cgi->XML_AddBoolValue(aimed, SAVE_AIRFIGHT_ISUFO, AIR_IsUFO(projectile->aimedAircraft));
            if (AIR_IsUFO(projectile->aimedAircraft))
                cgi->XML_AddInt(aimed, SAVE_AIRFIGHT_AIRCRAFTIDX, UFO_GetGeoscapeIDX(projectile->aimedAircraft));
            else
                cgi->XML_AddInt(aimed, SAVE_AIRFIGHT_AIRCRAFTIDX, projectile->aimedAircraft->idx);
        }
    }

    return true;
}

bool AIRFIGHT_LoadXML (xmlNode_t* parent)
{
    int i;
    xmlNode_t* node;

    for (i = 0, node = cgi->XML_GetNode(parent, SAVE_AIRFIGHT_PROJECTILE); i < MAX_PROJECTILESONGEOSCAPE && node;
            node = cgi->XML_GetNextNode(node, parent, SAVE_AIRFIGHT_PROJECTILE), i++) {
        technology_t* tech = RS_GetTechByProvided(cgi->XML_GetString(node, SAVE_AIRFIGHT_ITEMID));
        int j;
        xmlNode_t* positions;
        xmlNode_t* attackingAircraft;
        xmlNode_t* aimedAircraft;
        aircraftProjectile_t* projectile = &ccs.projectiles[i];

        if (!tech) {
            cgi->Com_Printf("AIR_Load: Could not get technology of projectile %i\n", i);
            return false;
        }

        projectile->aircraftItem = INVSH_GetItemByID(tech->provides);

        for (j = 0, positions = cgi->XML_GetPos2(node, SAVE_AIRFIGHT_POS, projectile->pos[0]); j < MAX_MULTIPLE_PROJECTILES && positions;
            j++, positions = cgi->XML_GetNextPos2(positions, node, SAVE_AIRFIGHT_POS, projectile->pos[j]))
            ;
        projectile->numProjectiles = j;
        cgi->XML_GetPos3(node, SAVE_AIRFIGHT_IDLETARGET, projectile->idleTarget);

        projectile->time = cgi->XML_GetInt(node, SAVE_AIRFIGHT_TIME, 0);
        projectile->angle = cgi->XML_GetFloat(node, SAVE_AIRFIGHT_ANGLE, 0.0);
        projectile->bullets = cgi->XML_GetBool(node, SAVE_AIRFIGHT_BULLET, false);
        projectile->beam = cgi->XML_GetBool(node, SAVE_AIRFIGHT_BEAM, false);

        if ((attackingAircraft = cgi->XML_GetNode(node, SAVE_AIRFIGHT_ATTACKINGAIRCRAFT))) {
            if (cgi->XML_GetBool(attackingAircraft, SAVE_AIRFIGHT_ISUFO, false))
                projectile->attackingAircraft = UFO_GetByIDX(cgi->XML_GetInt(attackingAircraft, SAVE_AIRFIGHT_AIRCRAFTIDX, 0));
            else
                projectile->attackingAircraft = AIR_AircraftGetFromIDX(cgi->XML_GetInt(attackingAircraft, SAVE_AIRFIGHT_AIRCRAFTIDX, AIRCRAFT_INVALID));
        } else {
            projectile->attackingAircraft = nullptr;
        }
        cgi->XML_GetPos3(node, SAVE_AIRFIGHT_ATTACKERPOS, projectile->attackerPos);

        if ((aimedAircraft = cgi->XML_GetNode(node, SAVE_AIRFIGHT_AIMEDAIRCRAFT))) {
            if (cgi->XML_GetBool(aimedAircraft, SAVE_AIRFIGHT_ISUFO, false))
                projectile->aimedAircraft = UFO_GetByIDX(cgi->XML_GetInt(aimedAircraft, SAVE_AIRFIGHT_AIRCRAFTIDX, 0));
            else
                projectile->aimedAircraft = AIR_AircraftGetFromIDX(cgi->XML_GetInt(aimedAircraft, SAVE_AIRFIGHT_AIRCRAFTIDX, AIRCRAFT_INVALID));
        } else {
            projectile->aimedAircraft = nullptr;
        }
    }
    ccs.numProjectiles = i;

    return true;
}

void AIRFIGHT_InitStartup (void)
{
#ifdef DEBUG
    cgi->Cmd_AddCommand("debug_listprojectile", AIRFIGHT_ProjectileList_f, "Print Projectiles information to game console");
#endif
}