sv_world.cpp

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

Original file from Quake 2 v3.21: quake2-2.31/server/sv_world.c
Copyright (C) 1997-2001 Id Software, Inc.

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 "../shared/moveclip.h"
#include "server.h"
#include "../common/qfiles.h"

#define AREA_DEPTH  4

static worldSector_t* SV_CreateWorldSector (int depth, const AABB& sBox)
{
    if (sv->numWorldSectors >= lengthof(sv->worldSectors))
        Com_Error(ERR_DROP, "SV_CreateWorldSector: overflow");

    worldSector_t* anode = &sv->worldSectors[sv->numWorldSectors];
    sv->numWorldSectors++;

    anode->entities = nullptr;

    if (depth == AREA_DEPTH) {
        anode->axis = LEAFNODE; /* end of tree */
        anode->children[0] = anode->children[1] = nullptr;
        return anode;
    }

    vec3_t size;
    sBox.getDiagonal(size);
    if (size[0] > size[1])
        anode->axis = PLANE_X;
    else
        anode->axis = PLANE_Y;

    anode->dist = 0.5f * (sBox.maxs[anode->axis] + sBox.mins[anode->axis]);
    AABB sBox1(sBox);
    AABB sBox2(sBox);

    sBox1.maxs[anode->axis] = sBox2.mins[anode->axis] = anode->dist;

    anode->children[0] = SV_CreateWorldSector(depth + 1, sBox2);
    anode->children[1] = SV_CreateWorldSector(depth + 1, sBox1);

    return anode;
}

void SV_ClearWorld (void)
{
    SV_CreateWorldSector(0, sv->mapData.mapBox);
}

static inline sv_edict_t* SV_GetServerDataForEdict (const edict_t* ent)
{
    if (!ent || ent->number < 0 || ent->number >= lengthof(sv->edicts))
        Com_Error(ERR_DROP, "SV_GetServerDataForEdict: bad game ent");

    return &sv->edicts[ent->number];
}

void SV_UnlinkEdict (edict_t* ent)
{
    sv_edict_t* sv_ent = SV_GetServerDataForEdict(ent);
    sv_edict_t* scan;
    worldSector_t* ws;

    sv_ent->linked = false;

    ws = sv_ent->worldSector;
    if (!ws)
        return;                 /* not linked in anywhere */

    sv_ent->worldSector = nullptr;

    if (ws->entities == sv_ent) {
        ws->entities = sv_ent->nextEntityInWorldSector;
        return;
    }

    for (scan = ws->entities; scan; scan = scan->nextEntityInWorldSector) {
        if (scan->nextEntityInWorldSector == sv_ent) {
            scan->nextEntityInWorldSector = sv_ent->nextEntityInWorldSector;
            return;
        }
    }

    Com_Printf("WARNING: SV_UnlinkEntity: not found in worldSector\n");
}

void SV_LinkEdict (edict_t* ent)
{
    worldSector_t* node;
    sv_edict_t* sv_ent = SV_GetServerDataForEdict(ent);

    if (sv_ent->worldSector)
        SV_UnlinkEdict(ent);    /* unlink from old position */

    if (ent == svs.ge->edicts)
        return;                 /* don't add the world */

    if (!ent->inuse)
        return;

    /* set the size */
    ent->entBox.getDiagonal(ent->size);

    /* increase the linkcount - even for none solids */
    ent->linkcount++;

    CalculateMinsMaxs(ent->solid == SOLID_BSP ? ent->angles : vec3_origin, ent->entBox, ent->origin, ent->absBox);

    /* if not solid we have to set the abs mins/maxs above but don't really link it */
    if (ent->solid == SOLID_NOT)
        return;

    /* find the first node that the ent's box crosses */
    node = sv->worldSectors;
    while (1) {
        /* end of tree */
        if (node->axis == LEAFNODE)
            break;
        if (ent->absBox.mins[node->axis] > node->dist)
            node = node->children[0];
        else if (ent->absBox.maxs[node->axis] < node->dist)
            node = node->children[1];
        else
            break;              /* crosses the node */
    }

    /* link it in */
    sv_ent->nextEntityInWorldSector = node->entities;
    node->entities = sv_ent;

    sv_ent->linked = true;
    sv_ent->worldSector = node;
    sv_ent->ent = ent;

    /* If this ent has a child, link it back in, too */
    if (ent->child()) {
        ent->child()->entBox.set(ent->absBox);

        /* expand the trigger box */
        ent->child()->entBox.expandXY(UNIT_SIZE / 2);
        /* link child back into the world */
        SV_LinkEdict(ent->child());
    }
}

static bool SV_BoundingBoxesIntersect (const AABB& aabb, const edict_t* ent)
{
    return aabb.doesIntersect(ent->absBox);
}

typedef struct {
    AABB areaBox;
    edict_t** areaEdictList;
    int areaEdictListCount, areaEdictListMaxCount;
} areaParms_t;

static void SV_AreaEdicts_r (worldSector_t* node, areaParms_t* ap)
{
    sv_edict_t* check, *next;

    for (check = node->entities; check; check = next) {
        next = check->nextEntityInWorldSector;

        /* deactivated */
        if (check->ent->solid == SOLID_NOT)
            continue;

        if (!check->ent->inuse)
            continue;

        if (!SV_BoundingBoxesIntersect(ap->areaBox, check->ent))
            continue;           /* not touching */

        if (ap->areaEdictListCount == ap->areaEdictListMaxCount) {
            Com_Printf("SV_AreaEdicts_r: MAXCOUNT\n");
            return;
        }

        ap->areaEdictList[ap->areaEdictListCount] = check->ent;
        ap->areaEdictListCount++;
    }

    if (node->axis == LEAFNODE)
        return;                 /* terminal node - end of tree */

    /* recurse down both sides */
    if (ap->areaBox.maxs[node->axis] > node->dist)
        SV_AreaEdicts_r(node->children[0], ap);
    if (ap->areaBox.mins[node->axis] < node->dist)
        SV_AreaEdicts_r(node->children[1], ap);
}

static int SV_AreaEdicts (const AABB& abox, edict_t** list, int maxCount)
{
    areaParms_t ap;

    ap.areaBox.set(abox);
    ap.areaEdictList = list;
    ap.areaEdictListCount = 0;
    ap.areaEdictListMaxCount = maxCount;

    SV_AreaEdicts_r(sv->worldSectors, &ap);

    return ap.areaEdictListCount;
}

class MoveClipSV : public MoveClip
{
public:
    trace_t trace;
    const edict_t* passedict;
};


static int SV_HullForEntity (const edict_t* ent, int* tile, vec3_t rmaShift)
{
    assert(ent->solid != SOLID_NOT);
    assert(ent->solid != SOLID_TRIGGER);

    /* decide which clipping hull to use, based on the size */
    if (ent->solid == SOLID_BSP) {  /* explicit hulls in the BSP model */
        const cBspModel_t* model;

        assert(ent->modelindex < MAX_MODELS);

        model = sv->models[ent->modelindex];
        if (!model)
            Com_Error(ERR_FATAL, "SOLID_BSP with a non bsp model");

        *tile = model->tile;
        VectorCopy(model->shift, rmaShift);
        assert(model->headnode < MAX_MAP_NODES);
        return model->headnode;
    }

    /* create a temp hull from bounding box sizes */
    *tile = 0;
    VectorCopy(vec3_origin, rmaShift);
    return CM_HeadnodeForBox(sv->mapTiles.mapTiles[*tile], ent->entBox);
}


static void SV_ClipMoveToEntities (MoveClipSV* clip)
{
    edict_t* touchlist[MAX_EDICTS];
    const int num = SV_AreaEdicts(clip->clipBox, touchlist, MAX_EDICTS);

    /* be careful, it is possible to have an entity in this
     * list removed before we get to it (killtriggered) */
    for (int i = 0; i < num; i++) {
        vec3_t rmaShift;
        edict_t* touch = touchlist[i];
        int tile = 0;

        if (touch->solid == SOLID_NOT || touch->solid == SOLID_TRIGGER)
            continue;
        if (touch == clip->passedict)
            continue;

        if (clip->trace.allsolid)
            return;

        if (clip->passedict) {
            if (touch->isParentship(clip->passedict))   /* check if one of them is the owner of the other */
                continue;       /* don't clip against own missiles or owner */
        }

        /* might intersect, so do an exact clip */
        int headnode = SV_HullForEntity(touch, &tile, rmaShift);
        if (headnode >= MAX_MAP_NODES)
            continue;

        const float* angles;
        if (touch->solid != SOLID_BSP)
            angles = vec3_origin;   /* boxes don't rotate */
        else
            angles = touch->angles;

        assert(headnode < MAX_MAP_NODES);
        trace_t trace = CM_HintedTransformedBoxTrace(sv->mapTiles.mapTiles[tile], clip->moveLine, clip->objBox, headnode,
                clip->contentmask, 0, touch->origin, angles, rmaShift, 1.0);

#ifdef PARANOID
        Com_DPrintf(DEBUG_SERVER, "SV_ClipMoveToEntities: %i %i: (%i %i %i) (%i %i %i) (%i %i %i)\n", touch->number, touch->modelindex,
            (int)touch->entBox.mins[0], (int)touch->entBox.mins[1], (int)touch->entBox.mins[2],
            (int)touch->entBox.maxs[0], (int)touch->entBox.maxs[1], (int)touch->entBox.maxs[2],
            (int)touch->origin[0], (int)touch->origin[1], (int)touch->origin[2]);
#endif

        if (trace.fraction < clip->trace.fraction) {
            bool oldStart;

            /* make sure we keep a startsolid from a previous trace */
            oldStart = clip->trace.startsolid;
            trace.entNum = touch->number;
            clip->trace = trace;
            clip->trace.startsolid |= oldStart;
        } else if (trace.allsolid) {
            trace.entNum = touch->number;
            clip->trace = trace;
        } else if (trace.startsolid) {
            trace.entNum = touch->number;
            clip->trace.startsolid = true;
        }
    }
}

int SV_PointContents (const vec3_t p)
{
    /* clip to all world levels */
    const trace_t trace = CM_CompleteBoxTrace(&sv->mapTiles, Line(p, p), AABB::EMPTY, TRACE_ALL_LEVELS, MASK_ALL, 0);
    if (trace.fraction == 0)
        return trace.contentFlags;      /* blocked by the world */
    return 0;
}

trace_t SV_Trace (const Line& traceLine, const AABB& box, const edict_t* passedict, int contentmask)
{
    MoveClipSV clip;

    OBJZERO(clip);

    /* clip to world - 0x1FF = all levels */
    clip.trace = CM_CompleteBoxTrace(&sv->mapTiles, traceLine, box, TRACE_ALL_LEVELS, contentmask, 0);
    clip.trace.entNum = 0; /* the first edict is the world */
    if (clip.trace.fraction == 0)
        return clip.trace;      /* blocked by the world */

    clip.contentmask = contentmask;
    clip.moveLine.set(traceLine);
    clip.objBox.set(box);
    clip.passedict = passedict;

    /* create the bounding box for the entire path traveled by the shot */
    clip.calcBounds();

    /* clip to other solid entities */
    SV_ClipMoveToEntities(&clip);

    return clip.trace;
}

const char* SV_GetFootstepSound (const char* texture)
{
    const terrainType_t* t = Com_GetTerrainType(texture);
    return t ? t->footstepSound : nullptr;
}

float SV_GetBounceFraction (const char* texture)
{
    const terrainType_t* t = Com_GetTerrainType(texture);
    return t ? t->bounceFraction : 1.0f;
}

static void SV_ModLoadAliasMD2Model (sv_model_t* mod, const byte* buffer)
{
    const dMD2Model_t* md2 = (const dMD2Model_t*)buffer;
    const int num_frames = LittleLong(md2->num_frames);
    const int frameSize = LittleLong(md2->framesize);
    const dMD2Frame_t* frame = (const dMD2Frame_t*) ((const byte*) md2 + LittleLong(md2->ofs_frames) + mod->frame * frameSize);
    vec3_t scale, mins, maxs;

    if (mod->frame > num_frames)
        return;

    for (int j = 0; j < 3; j++) {
        scale[j] = LittleFloat(frame->scale[j]);
        mins[j] = LittleFloat(frame->translate[j]);
    }

    VectorMA(mins, 255, scale, maxs);
    mod->aabb.add(mins);
    mod->aabb.add(maxs);
}

static void SV_ModLoadAliasMD3Model (sv_model_t* mod, const byte* buffer)
{
    const dmd3_t* md3 = (const dmd3_t*)buffer;
    const dmd3frame_t* frame = (const dmd3frame_t*)((const byte*)md3 + LittleLong(md3->ofs_frames));
    const int num_frames = LittleLong(md3->num_frames);
    vec3_t mins, maxs;

    if (mod->frame > num_frames)
        return;

    frame += mod->frame;
    for (int j = 0; j < 3; j++) {
        mins[j] = LittleFloat(frame->mins[j]);
        maxs[j] = LittleFloat(frame->maxs[j]);
    }
    mod->aabb.add(mins);
    mod->aabb.add(maxs);
}

static void SV_ModLoadObjModel (sv_model_t* mod, const byte* buffer, int bufferLength)
{
}

static char const* const mod_extensions[] = {
    "md2", "md3", "obj", nullptr
};

bool SV_LoadModelAABB (const char* model, int frame, AABB& aabb)
{
    sv_model_t* mod;
    byte* buf = nullptr;
    unsigned int i;
    int modfilelen = 0;

    if (model[0] == '\0')
        Com_Error(ERR_DROP, "SV_LoadModelAABB: nullptr model");

    /* search the currently loaded models */
    for (i = 0, mod = sv->svModels; i < sv->numSVModels; i++, mod++)
        if (mod->frame == frame && Q_streq(mod->name, model)) {
            aabb.set(mod->aabb);
            return true;
        }

    /* find a free model slot spot */
    for (i = 0, mod = sv->svModels; i < sv->numSVModels; i++, mod++) {
        if (!mod->name)
            break;              /* free spot */
    }

    if (i == sv->numSVModels) {
        if (sv->numSVModels == MAX_MOD_KNOWN)
            Com_Error(ERR_DROP, "sv->numSVModels == MAX_MOD_KNOWN");
        sv->numSVModels++;
    }

    aabb.reset();

    /* load the file */
    if (Com_GetExtension(model) == nullptr) {
        char filename[MAX_QPATH];

        for (i = 0; mod_extensions[i] != nullptr; i++) {
            Com_sprintf(filename, sizeof(filename), "%s.%s", model, mod_extensions[i]);
            modfilelen = FS_LoadFile(filename, &buf);
            if (buf) {
                break;
            }
        }
    } else {
        modfilelen = FS_LoadFile(model, &buf);
    }

    if (!buf) {
        sv->numSVModels--;
        return false;
    }

    OBJZERO(*mod);
    mod->name = Mem_PoolStrDup(model, com_genericPool, 0);
    mod->frame = frame;
    mod->aabb.setNegativeVolume();

    /* call the appropriate loader */
    switch (LittleLong(*(unsigned* ) buf)) {
    case IDALIASHEADER:
        SV_ModLoadAliasMD2Model(mod, buf);
        break;

    case IDMD3HEADER:
        SV_ModLoadAliasMD3Model(mod, buf);
        break;

    default:
        if (!Q_strcasecmp(mod->name + strlen(mod->name) - 4, ".obj"))
            SV_ModLoadObjModel(mod, buf, modfilelen);
        else {
            FS_FreeFile(buf);
            return false;
        }
        break;
    }

    aabb.set(mod->aabb);    /* to return the found values */

    FS_FreeFile(buf);
    return true;
}