bspbrush.cpp

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/*
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 "bsp.h"
#include "map.h"
 
extern int c_nodes;
extern int c_nonvis;
static int c_active_brushes;
 

static void BoundBrush (bspbrush_t* brush)
{
    brush->brBox.setNegativeVolume();
    for (int i = 0; i < brush->numsides; i++) {
        winding_t* w = brush->sides[i].winding;
        if (!w)
            continue;
        for (int j = 0; j < w->numpoints; j++)
            brush->brBox.add(w->p[j]);
    }
}
 

static void CreateBrushWindings (bspbrush_t* brush)
{
    for (int i = 0; i < brush->numsides; i++) {
        side_t* side = &brush->sides[i];
        const plane_t* plane = &mapplanes[side->planenum];
 
        /* evidence that winding_t represents a hessian normal plane */
        winding_t* w = BaseWindingForPlane(plane->normal, plane->dist);
 
        for (int j = 0; j < brush->numsides && w; j++) {
            if (i == j)
                continue;
            /* back side clipaway */
            if (brush->sides[j].planenum == (side->planenum ^ 1))
                continue;
            if (brush->sides[j].bevel)
                continue;
            plane = &mapplanes[brush->sides[j].planenum ^ 1];
            ChopWindingInPlace(&w, plane->normal, plane->dist, 0); /*CLIP_EPSILON); */
 
            /* fix broken windings that would generate trifans */
            if (!FixWinding(w))
                Verb_Printf(VERB_EXTRA, "removed degenerated edge(s) from winding\n");
        }
 
        side->winding = w;
    }
 
    BoundBrush(brush);
}

bspbrush_t* BrushFromBounds (const vec3_t mins, const vec3_t maxs)
{
    vec3_t normal;
 
    bspbrush_t* b = AllocBrush(6);
    b->numsides = 6;
    for (int i = 0; i < 3; i++) {
        VectorClear(normal);
        normal[i] = 1;
        vec_t dist = maxs[i];
        b->sides[i].planenum = FindOrCreateFloatPlane(normal, dist);
 
        normal[i] = -1;
        dist = -mins[i];
        b->sides[3 + i].planenum = FindOrCreateFloatPlane(normal, dist);
    }
 
    CreateBrushWindings(b);
 
    return b;
}

static vec_t BrushVolume (const bspbrush_t* brush)
{
    int i;
    const winding_t* w;
    vec3_t corner;
    vec_t volume;
 
    if (!brush)
        return 0;
 
    /* grab the first valid point as the corner */
    w = nullptr;
    for (i = 0; i < brush->numsides; i++) {
        w = brush->sides[i].winding;
        if (w)
            break;
    }
    if (!w)
        return 0;
    VectorCopy(w->p[0], corner);
 
    /* make tetrahedrons to all other faces */
    volume = 0;
    for (; i < brush->numsides; i++) {
        w = brush->sides[i].winding;
        if (w) {
            const plane_t* plane = &mapplanes[brush->sides[i].planenum];
            const vec_t d = -(DotProduct(corner, plane->normal) - plane->dist);
            const vec_t area = WindingArea(w);
            volume += d * area;
        }
    }
 
    volume /= 3;
    return volume;
}

int CountBrushList (bspbrush_t* brushes)
{
    int c;
 
    c = 0;
    for (; brushes; brushes = brushes->next)
        c++;
    return c;
}

bspbrush_t* AllocBrush (int numsides)
{
    const size_t size = sizeof(bspbrush_t) + sizeof(side_t) * (numsides - STANDARD_NUMBER_OF_BRUSHSIDES);
 
    if (threadstate.numthreads == 1)
        c_active_brushes++;
 
    return (bspbrush_t*)Mem_Alloc(size);
}

void FreeBrush (bspbrush_t* brushes)
{
    for (int i = 0; i < brushes->numsides; i++)
        if (brushes->sides[i].winding)
            FreeWinding(brushes->sides[i].winding);
    Mem_Free(brushes);
    if (threadstate.numthreads == 1)
        c_active_brushes--;
}

void FreeBrushList (bspbrush_t* brushes)
{
    bspbrush_t* next;
 
    for (; brushes; brushes = next) {
        next = brushes->next;
        FreeBrush(brushes);
    }
}

bspbrush_t* CopyBrush (const bspbrush_t* brush)
{
    const size_t size = sizeof(bspbrush_t) + sizeof(side_t) * (brush->numsides - STANDARD_NUMBER_OF_BRUSHSIDES);
 
    bspbrush_t* newbrush = AllocBrush(brush->numsides);
    memcpy(newbrush, brush, size);
 
    for (int i = 0; i < brush->numsides; i++) {
        const side_t* side = &brush->sides[i];
        if (side->winding)
            newbrush->sides[i].winding = CopyWinding(side->winding);
    }
 
    return newbrush;
}
 
 
static int TestBrushToPlanenum (bspbrush_t* brush, uint16_t planenum,
            int* numsplits, bool* hintsplit, int* epsilonbrush)
{
    int i, s;
    plane_t* plane;
    dBspPlane_t plane2;
    vec_t d_front, d_back;
    int front, back;
 
    *numsplits = 0;
    *hintsplit = false;
 
    /* if the brush actually uses the planenum,
     * we can tell the side for sure */
    for (i = 0; i < brush->numsides; i++) {
        const uint16_t num = brush->sides[i].planenum;
        if (num == planenum)
            return (PSIDE_BACK | PSIDE_FACING);
        if (num == (planenum ^ 1))
            return (PSIDE_FRONT | PSIDE_FACING);
    }
 
    /* box on plane side */
    plane = &mapplanes[planenum];
 
    /* Convert to cBspPlane */
    VectorCopy(plane->normal, plane2.normal);
    plane2.dist = plane->dist;
    plane2.type = plane->type;
    s = TR_BoxOnPlaneSide(brush->brBox.mins, brush->brBox.maxs, &plane2);
 
    if (s != PSIDE_BOTH)
        return s;
 
    /* if both sides, count the visible faces split */
    d_front = d_back = 0;
 
    for (i = 0; i < brush->numsides; i++) {
        const side_t* side = &brush->sides[i];
        const winding_t* w;
        if (side->texinfo == TEXINFO_NODE)
            continue;       /* on node, don't worry about splits */
        if (!side->visible)
            continue;       /* we don't care about non-visible */
        w = side->winding;
        if (!w)
            continue;
        front = back = 0;
        for (int j = 0; j < w->numpoints; j++) {
            const vec_t d = DotProduct(w->p[j], plane->normal) - plane->dist;
            if (d > d_front)
                d_front = d;
            if (d < d_back)
                d_back = d;
 
            if (d > 0.1) /* PLANESIDE_EPSILON) */
                front = 1;
            else if (d < -0.1) /* PLANESIDE_EPSILON) */
                back = 1;
        }
        if (front && back) {
            (*numsplits)++;
            if (side->surfaceFlags & SURF_HINT)
                *hintsplit = true;
        }
    }
 
    if ((d_front > 0.0 && d_front < 1.0) || (d_back < 0.0 && d_back > -1.0))
        (*epsilonbrush)++;
 
    return s;
}

uint32_t BrushListCalcContents (bspbrush_t* brushlist)
{
    bspbrush_t* b;
    uint32_t contentFlags = 0;
 
    for (b = brushlist; b; b = b->next) {
        /* if the brush is solid and all of its sides are on nodes,
         * it eats everything */
        if ((b->original->contentFlags & CONTENTS_SOLID) && !(b->original->contentFlags & CONTENTS_PASSABLE)) {
            int i;
            for (i = 0; i < b->numsides; i++)
                if (b->sides[i].texinfo != TEXINFO_NODE)
                    break;
            if (i == b->numsides) {
                contentFlags = CONTENTS_SOLID;
                break;
            }
        }
        contentFlags |= b->original->contentFlags;
    }
 
    return contentFlags;
}

static int BrushMostlyOnSide (const bspbrush_t* brush, const plane_t* plane)
{
    vec_t max = 0;
    int side = PSIDE_FRONT;
 
    for (int i = 0; i < brush->numsides; i++) {
        const winding_t* w = brush->sides[i].winding;
        if (!w)
            continue;
        for (int j = 0; j < w->numpoints; j++) {
            const vec_t d = DotProduct(w->p[j], plane->normal) - plane->dist;
            if (d > max) {
                max = d;
                side = PSIDE_FRONT;
            }
            if (-d > max) {
                max = -d;
                side = PSIDE_BACK;
            }
        }
    }
    return side;
}
 
#define TESTING_MOCK_SPLIT 1
#if TESTING_MOCK_SPLIT
static bool DoesPlaneSplitBrush (const bspbrush_t* brush, int planenum)
{
    plane_t* plane  = &mapplanes[planenum];
    int front_cnt = 0, back_cnt = 0;
 
    /* check all points */
    for (int i = 0; i < brush->numsides; i++) {
        winding_t* w = brush->sides[i].winding;
        if (!w)
            continue;
        for (int j = 0; j < w->numpoints; j++) {
            const float d = DotProduct(w->p[j], plane->normal) - plane->dist;
            if (d > 0.1f) /* PLANESIDE_EPSILON) */
                front_cnt++;
            if (d < -0.1f) /* PLANESIDE_EPSILON) */
                back_cnt++;
        }
    }
 
    /* if brush vertices are both in front and back of given plane, in splits brush */
    return front_cnt && back_cnt ;
}
#endif
 
#if TESTING_MOCK_SPLIT
/* DoesPlaneSplitBrush does not yet work for all maps, namely city_train.map
 * Until we know why, let's use the old stuff. */
static bool CheckPlaneAgainstVolume (int pnum, const bspbrush_t* volume)
{
    bool good;
 
    good = DoesPlaneSplitBrush(volume, pnum);
 
    return good;
}
 
#else
static bool CheckPlaneAgainstVolume (uint16_t pnum, const bspbrush_t* volume)
{
        bspbrush_t* front, *back;
        bool good;
 
        SplitBrush(volume, pnum, &front, &back);
 
        good = (front && back);
 
        if (front)
                FreeBrush(front);
        if (back)
                FreeBrush(back);
 
        return good;
}
#endif
side_t* SelectSplitSide (bspbrush_t* brushes, bspbrush_t* volume)
{
    int value;
    bspbrush_t* brush, *test;
    int i, pass;
    int front, back, both, facing, splits;
    int bsplits, epsilonbrush;
    bool hintsplit;
 
    if (!volume)
        return nullptr; /* can't split empty brush */
 
    side_t* bestside = nullptr;
    int bestvalue = -99999;

    int numpasses = 4;
    for (pass = 0; pass < numpasses; pass++) {
        for (brush = brushes; brush; brush = brush->next) {
            if ((pass & 1) && !(brush->original->contentFlags & CONTENTS_DETAIL))
                continue;
            if (!(pass & 1) && (brush->original->contentFlags & CONTENTS_DETAIL))
                continue;
            for (i = 0; i < brush->numsides; i++) {
                uint16_t pnum;
                side_t* side = &brush->sides[i];
                if (side->bevel)
                    continue;   /* never use a bevel as a spliter */
                if (!side->winding)
                    continue;   /* nothing visible, so it can't split */
                if (side->texinfo == TEXINFO_NODE)
                    continue;   /* already a node splitter */
                if (side->tested)
                    continue;   /* we already have metrics for this plane */
                if (side->surfaceFlags & SURF_SKIP)
                    continue;   /* skip surfaces are never chosen */
                if (side->visible ^ (pass < 2))
                    continue;   /* only check visible faces on first pass */
 
                pnum = side->planenum;
                pnum &= ~1; /* always use positive facing plane */
 
                if (!CheckPlaneAgainstVolume(pnum, volume))
                    continue;   /* would produce a tiny volume */
 
                front = 0;
                back = 0;
                both = 0;
                facing = 0;
                splits = 0;
                epsilonbrush = 0;
                hintsplit = false;
 
                for (test = brushes; test; test = test->next) {
                    const int s = TestBrushToPlanenum(test, pnum, &bsplits, &hintsplit, &epsilonbrush);
 
                    splits += bsplits;
                    if (bsplits && (s & PSIDE_FACING))
                        Sys_Error("PSIDE_FACING with splits");
 
                    test->testside = s;
                    /* if the brush shares this face, don't bother
                     * testing that facenum as a splitter again */
                    if (s & PSIDE_FACING) {
                        facing++;
                        for (int j = 0; j < test->numsides; j++) {
                            if ((test->sides[j].planenum &~ 1) == pnum)
                                test->sides[j].tested = true;
                        }
                    }
                    if (s & PSIDE_FRONT)
                        front++;
                    if (s & PSIDE_BACK)
                        back++;
                    if (s == PSIDE_BOTH)
                        both++;
                }
 
                /* give a value estimate for using this plane */
 
                value = 5 * facing - 5 * splits - abs(front - back);
                if (AXIAL(&mapplanes[pnum]))
                    value += 5;     /* axial is better */
                value -= epsilonbrush * 1000;   /* avoid! */
 
                /* never split a hint side except with another hint */
                if (hintsplit && !(side->surfaceFlags & SURF_HINT))
                    value = -9999999;
 
                /* save off the side test so we don't need
                 * to recalculate it when we actually seperate
                 * the brushes */
                if (value > bestvalue) {
                    bestvalue = value;
                    bestside = side;
                    for (test = brushes; test; test = test->next)
                        test->side = test->testside;
                }
            }
        }
 
        /* if we found a good plane, don't bother trying any other passes */
        if (bestside) {
            if (pass > 1) {
                if (threadstate.numthreads == 1)
                    c_nonvis++;
            }
            break;
        }
    }
 
    /* clear all the tested flags we set */
    for (brush = brushes; brush; brush = brush->next) {
        for (i = 0; i < brush->numsides; i++)
            brush->sides[i].tested = false;
    }
 
    return bestside;
}

void SplitBrush (const bspbrush_t* brush, uint16_t planenum, bspbrush_t** front, bspbrush_t** back)
{
    bspbrush_t* b[2];
    int i, j;
    winding_t* w, *cw[2], *midwinding;
    plane_t* plane;
    float d_front, d_back;
 
    *front = *back = nullptr;
    plane = &mapplanes[planenum];
 
    /* check all points */
    d_front = d_back = 0;
    for (i = 0; i < brush->numsides; i++) {
        w = brush->sides[i].winding;
        if (!w)
            continue;
        for (j = 0; j < w->numpoints; j++) {
            const float d = DotProduct(w->p[j], plane->normal) - plane->dist;
            if (d > 0 && d > d_front)
                d_front = d;
            else if (d < 0 && d < d_back)
                d_back = d;
        }
    }
    if (d_front < 0.1) { /* PLANESIDE_EPSILON) */
        /* only on back */
        *back = CopyBrush(brush);
        return;
    }
    if (d_back > -0.1) { /* PLANESIDE_EPSILON) */
        /* only on front */
        *front = CopyBrush(brush);
        return;
    }
 
    /* create a new winding from the split plane */
    w = BaseWindingForPlane(plane->normal, plane->dist);
    for (i = 0; i < brush->numsides && w; i++) {
        plane_t* plane2 = &mapplanes[brush->sides[i].planenum ^ 1];
        ChopWindingInPlace(&w, plane2->normal, plane2->dist, 0); /* PLANESIDE_EPSILON); */
    }
 
    /* the brush isn't really split */
    if (!w || WindingIsTiny(w)) {
        const int side = BrushMostlyOnSide(brush, plane);
        if (side == PSIDE_FRONT)
            *front = CopyBrush(brush);
        else if (side == PSIDE_BACK)
            *back = CopyBrush(brush);
        return;
    }
 
    if (WindingIsHuge(w)) {
        Com_Printf("WARNING: Large winding\n");
    }
 
    midwinding = w;
 
    /* split it for real */
    for (i = 0; i < 2; i++) {
        b[i] = AllocBrush(brush->numsides + 1);
        b[i]->original = brush->original;
    }
 
    /* split all the current windings */
    for (i = 0; i < brush->numsides; i++) {
        const side_t* s = &brush->sides[i];
        w = s->winding;
        if (!w)
            continue;
        ClipWindingEpsilon(w, plane->normal, plane->dist,
            0 /*PLANESIDE_EPSILON*/, &cw[0], &cw[1]);
        for (j = 0; j < 2; j++) {
            side_t* cs;
 
            if (!cw[j])
                continue;
 
            cs = &b[j]->sides[b[j]->numsides];
            b[j]->numsides++;
            *cs = *s;
 
            cs->winding = cw[j];
            cs->tested = false;
        }
    }
 
    /* see if we have valid polygons on both sides */
    for (i = 0; i < 2; i++) {
        BoundBrush(b[i]);
        for (j = 0; j < 3; j++) {
            if (b[i]->brBox.mins[j] < -MAX_WORLD_WIDTH || b[i]->brBox.maxs[j] > MAX_WORLD_WIDTH) {
                Verb_Printf(VERB_EXTRA, "bogus brush after clip\n");
                break;
            }
        }
 
        if (b[i]->numsides < 3 || j < 3) {
            FreeBrush(b[i]);
            b[i] = nullptr;
        }
    }
 
    if (!(b[0] && b[1])) {
        if (!b[0] && !b[1])
            Verb_Printf(VERB_EXTRA, "split removed brush\n");
        else
            Verb_Printf(VERB_EXTRA, "split not on both sides\n");
        if (b[0]) {
            FreeBrush(b[0]);
            *front = CopyBrush(brush);
        }
        if (b[1]) {
            FreeBrush(b[1]);
            *back = CopyBrush(brush);
        }
        return;
    }
 
    /* add the midwinding to both sides */
    for (i = 0; i < 2; i++) {
        side_t* cs = &b[i]->sides[b[i]->numsides];
        b[i]->numsides++;
 
        cs->planenum = planenum ^ i ^ 1;
        cs->texinfo = TEXINFO_NODE;
        cs->visible = false;
        cs->tested = false;
        if (i == 0)
            cs->winding = CopyWinding(midwinding);
        else
            cs->winding = midwinding;
    }
 
    for (i = 0; i < 2; i++) {
        const vec_t v1 = BrushVolume(b[i]);
        if (v1 < 1.0) {
            FreeBrush(b[i]);
            b[i] = nullptr;
            Verb_Printf(VERB_EXTRA, "tiny volume after clip\n");
        }
    }
 
    *front = b[0];
    *back = b[1];
}
 
void SplitBrushList (bspbrush_t* brushes, uint16_t planenum, bspbrush_t** front, bspbrush_t** back)
{
    bspbrush_t* brush;
 
    *front = *back = nullptr;
 
    for (brush = brushes; brush; brush = brush->next) {
        const int sides = brush->side;
        bspbrush_t* newbrush;
 
        if (sides == PSIDE_BOTH) {  /* split into two brushes */
            bspbrush_t* newbrush2;
            SplitBrush(brush, planenum, &newbrush, &newbrush2);
            if (newbrush) {
                newbrush->next = *front;
                Verb_Printf(VERB_DUMP, "SplitBrushList: Adding brush %i to front list.\n", newbrush->original->brushnum);
                *front = newbrush;
            }
            if (newbrush2) {
                newbrush2->next = *back;
                Verb_Printf(VERB_DUMP, "SplitBrushList: Adding brush %i to back list.\n", newbrush2->original->brushnum);
                *back = newbrush2;
            }
            continue;
        }
 
        newbrush = CopyBrush(brush);
 
        /* if the planenum is actually a part of the brush
         * find the plane and flag it as used so it won't be tried
         * as a splitter again */
        if (sides & PSIDE_FACING) {
            for (int i = 0; i < newbrush->numsides; i++) {
                side_t* side = newbrush->sides + i;
                if ((side->planenum & ~1) == planenum)
                    side->texinfo = TEXINFO_NODE;
            }
        }
 
        if (sides & PSIDE_FRONT) {
            newbrush->next = *front;
            *front = newbrush;
            Verb_Printf(VERB_DUMP, "SplitBrushList: Adding brush %i to front list.\n", newbrush->original->brushnum);
            continue;
        }
        if (sides & PSIDE_BACK) {
            newbrush->next = *back;
            Verb_Printf(VERB_DUMP, "SplitBrushList: Adding brush %i to back list.\n", newbrush->original->brushnum);
            *back = newbrush;
            continue;
        }
        Verb_Printf(VERB_DUMP, "SplitBrushList: Brush %i fell off the map.\n", newbrush->original->brushnum);
    }
}
 

void BrushlistCalcStats (bspbrush_t* brushlist, AABB& blBox)
{
    bspbrush_t* b;
    int c_faces = 0, c_nonvisfaces = 0, c_brushes = 0;
 
    for (b = brushlist; b; b = b->next) {
        c_brushes++;
 
        vec_t volume = BrushVolume(b);
        if (volume < config.microvolume) {
            Com_Printf("\nWARNING: entity %i, brush %i: microbrush, volume %.3g\n",
                b->original->entitynum, b->original->brushnum, volume);
        }
 
        for (int i = 0; i < b->numsides; i++) {
            side_t* side = &b->sides[i];
            if (side->bevel)
                continue;
            if (!side->winding)
                continue;
            if (side->texinfo == TEXINFO_NODE)
                continue;
            if (side->visible)
                c_faces++;
            else
                c_nonvisfaces++;
        }
 
        blBox.add(b->brBox);
    }
 
    Verb_Printf(VERB_EXTRA, "%5i brushes\n", c_brushes);
    Verb_Printf(VERB_EXTRA, "%5i visible faces\n", c_faces);
    Verb_Printf(VERB_EXTRA, "%5i nonvisible faces\n", c_nonvisfaces);
}