rayobject_octree.cpp

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 1990-1998 NeoGeo BV.
 * All rights reserved.
 *
 * Contributors: 2004/2005 Blender Foundation, full recode
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/* IMPORTANT NOTE: this code must be independent of any other render code
   to use it outside the renderer! */

#include <math.h>
#include <string.h>
#include <stdlib.h>
#include <float.h>
#include <assert.h>

#include "MEM_guardedalloc.h"

#include "DNA_material_types.h"

#include "BLI_math.h"
#include "BLI_utildefines.h"

#include "rayintersection.h"
#include "rayobject.h"

/* ********** structs *************** */
#define BRANCH_ARRAY 1024
#define NODE_ARRAY 4096

typedef struct Branch
{
    struct Branch *b[8];
} Branch;

typedef struct OcVal 
{
    short ocx, ocy, ocz;
} OcVal;

typedef struct Node
{
    struct RayFace *v[8];
    struct OcVal ov[8];
    struct Node *next;
} Node;

typedef struct Octree {
    RayObject rayobj;

    struct Branch **adrbranch;
    struct Node **adrnode;
    float ocsize;   /* ocsize: mult factor,  max size octree */
    float ocfacx,ocfacy,ocfacz;
    float min[3], max[3];
    int ocres;
    int branchcount, nodecount;

    /* during building only */
    char *ocface; 
    
    RayFace **ro_nodes;
    int ro_nodes_size, ro_nodes_used;
    
} Octree;

static int  RE_rayobject_octree_intersect(RayObject *o, Isect *isec);
static void RE_rayobject_octree_add(RayObject *o, RayObject *ob);
static void RE_rayobject_octree_done(RayObject *o);
static void RE_rayobject_octree_free(RayObject *o);
static void RE_rayobject_octree_bb(RayObject *o, float *min, float *max);

/*
 * This function is not expected to be called by current code state.
 */
static float RE_rayobject_octree_cost(RayObject *UNUSED(o))
{
    return 1.0;
}

static void RE_rayobject_octree_hint_bb(RayObject *UNUSED(o), RayHint *UNUSED(hint),
                                        float *UNUSED(min), float *UNUSED(max))
{
    return;
}

static RayObjectAPI octree_api =
{
    RE_rayobject_octree_intersect,
    RE_rayobject_octree_add,
    RE_rayobject_octree_done,
    RE_rayobject_octree_free,
    RE_rayobject_octree_bb,
    RE_rayobject_octree_cost,
    RE_rayobject_octree_hint_bb
};

/* **************** ocval method ******************* */
/* within one octree node, a set of 3x15 bits defines a 'boundbox' to OR with */

#define OCVALRES    15
#define BROW16(min, max)      (((max)>=OCVALRES? 0xFFFF: (1<<(max+1))-1) - ((min>0)? ((1<<(min))-1):0) )

static void calc_ocval_face(float *v1, float *v2, float *v3, float *v4, short x, short y, short z, OcVal *ov)
{
    float min[3], max[3];
    int ocmin, ocmax;
    
    copy_v3_v3(min, v1);
    copy_v3_v3(max, v1);
    DO_MINMAX(v2, min, max);
    DO_MINMAX(v3, min, max);
    if(v4) {
        DO_MINMAX(v4, min, max);
    }
    
    ocmin= OCVALRES*(min[0]-x); 
    ocmax= OCVALRES*(max[0]-x);
    ov->ocx= BROW16(ocmin, ocmax);
    
    ocmin= OCVALRES*(min[1]-y); 
    ocmax= OCVALRES*(max[1]-y);
    ov->ocy= BROW16(ocmin, ocmax);
    
    ocmin= OCVALRES*(min[2]-z); 
    ocmax= OCVALRES*(max[2]-z);
    ov->ocz= BROW16(ocmin, ocmax);

}

static void calc_ocval_ray(OcVal *ov, float xo, float yo, float zo, float *vec1, float *vec2)
{
    int ocmin, ocmax;
    
    if(vec1[0]<vec2[0]) {
        ocmin= OCVALRES*(vec1[0] - xo);
        ocmax= OCVALRES*(vec2[0] - xo);
    } else {
        ocmin= OCVALRES*(vec2[0] - xo);
        ocmax= OCVALRES*(vec1[0] - xo);
    }
    ov->ocx= BROW16(ocmin, ocmax);

    if(vec1[1]<vec2[1]) {
        ocmin= OCVALRES*(vec1[1] - yo);
        ocmax= OCVALRES*(vec2[1] - yo);
    } else {
        ocmin= OCVALRES*(vec2[1] - yo);
        ocmax= OCVALRES*(vec1[1] - yo);
    }
    ov->ocy= BROW16(ocmin, ocmax);

    if(vec1[2]<vec2[2]) {
        ocmin= OCVALRES*(vec1[2] - zo);
        ocmax= OCVALRES*(vec2[2] - zo);
    } else {
        ocmin= OCVALRES*(vec2[2] - zo);
        ocmax= OCVALRES*(vec1[2] - zo);
    }
    ov->ocz= BROW16(ocmin, ocmax);
}

/* ************* octree ************** */

static Branch *addbranch(Octree *oc, Branch *br, short ocb)
{
    int index;
    
    if(br->b[ocb]) return br->b[ocb];
    
    oc->branchcount++;
    index= oc->branchcount>>12;
    
    if(oc->adrbranch[index]==NULL)
        oc->adrbranch[index]= (Branch*)MEM_callocN(4096*sizeof(Branch), "new oc branch");

    if(oc->branchcount>= BRANCH_ARRAY*4096) {
        printf("error; octree branches full\n");
        oc->branchcount=0;
    }
    
    return br->b[ocb]= oc->adrbranch[index]+(oc->branchcount & 4095);
}

static Node *addnode(Octree *oc)
{
    int index;
    
    oc->nodecount++;
    index= oc->nodecount>>12;
    
    if(oc->adrnode[index]==NULL)
        oc->adrnode[index]= (Node*)MEM_callocN(4096*sizeof(Node),"addnode");

    if(oc->nodecount> NODE_ARRAY*NODE_ARRAY) {
        printf("error; octree nodes full\n");
        oc->nodecount=0;
    }
    
    return oc->adrnode[index]+(oc->nodecount & 4095);
}

static int face_in_node(RayFace *face, short x, short y, short z, float rtf[][3])
{
    static float nor[3], d;
    float fx, fy, fz;
    
    // init static vars 
    if(face) {
        normal_tri_v3( nor,rtf[0], rtf[1], rtf[2]);
        d= -nor[0]*rtf[0][0] - nor[1]*rtf[0][1] - nor[2]*rtf[0][2];
        return 0;
    }
    
    fx= x;
    fy= y;
    fz= z;
    
    if((fx)*nor[0] + (fy)*nor[1] + (fz)*nor[2] + d > 0.0f) {
        if((fx+1)*nor[0] + (fy  )*nor[1] + (fz  )*nor[2] + d < 0.0f) return 1;
        if((fx  )*nor[0] + (fy+1)*nor[1] + (fz  )*nor[2] + d < 0.0f) return 1;
        if((fx+1)*nor[0] + (fy+1)*nor[1] + (fz  )*nor[2] + d < 0.0f) return 1;
    
        if((fx  )*nor[0] + (fy  )*nor[1] + (fz+1)*nor[2] + d < 0.0f) return 1;
        if((fx+1)*nor[0] + (fy  )*nor[1] + (fz+1)*nor[2] + d < 0.0f) return 1;
        if((fx  )*nor[0] + (fy+1)*nor[1] + (fz+1)*nor[2] + d < 0.0f) return 1;
        if((fx+1)*nor[0] + (fy+1)*nor[1] + (fz+1)*nor[2] + d < 0.0f) return 1;
    }
    else {
        if((fx+1)*nor[0] + (fy  )*nor[1] + (fz  )*nor[2] + d > 0.0f) return 1;
        if((fx  )*nor[0] + (fy+1)*nor[1] + (fz  )*nor[2] + d > 0.0f) return 1;
        if((fx+1)*nor[0] + (fy+1)*nor[1] + (fz  )*nor[2] + d > 0.0f) return 1;
    
        if((fx  )*nor[0] + (fy  )*nor[1] + (fz+1)*nor[2] + d > 0.0f) return 1;
        if((fx+1)*nor[0] + (fy  )*nor[1] + (fz+1)*nor[2] + d > 0.0f) return 1;
        if((fx  )*nor[0] + (fy+1)*nor[1] + (fz+1)*nor[2] + d > 0.0f) return 1;
        if((fx+1)*nor[0] + (fy+1)*nor[1] + (fz+1)*nor[2] + d > 0.0f) return 1;
    }
    
    return 0;
}

static void ocwrite(Octree *oc, RayFace *face, int quad, short x, short y, short z, float rtf[4][3])
{
    Branch *br;
    Node *no;
    short a, oc0, oc1, oc2, oc3, oc4, oc5;

    x<<=2;
    y<<=1;

    br= oc->adrbranch[0];

    if(oc->ocres==512) {
        oc0= ((x & 1024)+(y & 512)+(z & 256))>>8;
        br= addbranch(oc, br, oc0);
    }
    if(oc->ocres>=256) {
        oc0= ((x & 512)+(y & 256)+(z & 128))>>7;
        br= addbranch(oc, br, oc0);
    }
    if(oc->ocres>=128) {
        oc0= ((x & 256)+(y & 128)+(z & 64))>>6;
        br= addbranch(oc, br, oc0);
    }

    oc0= ((x & 128)+(y & 64)+(z & 32))>>5;
    oc1= ((x & 64)+(y & 32)+(z & 16))>>4;
    oc2= ((x & 32)+(y & 16)+(z & 8))>>3;
    oc3= ((x & 16)+(y & 8)+(z & 4))>>2;
    oc4= ((x & 8)+(y & 4)+(z & 2))>>1;
    oc5= ((x & 4)+(y & 2)+(z & 1));

    br= addbranch(oc, br,oc0);
    br= addbranch(oc, br,oc1);
    br= addbranch(oc, br,oc2);
    br= addbranch(oc, br,oc3);
    br= addbranch(oc, br,oc4);
    no= (Node *)br->b[oc5];
    if(no==NULL) br->b[oc5]= (Branch *)(no= addnode(oc));

    while(no->next) no= no->next;

    a= 0;
    if(no->v[7]) {      /* node full */
        no->next= addnode(oc);
        no= no->next;
    }
    else {
        while(no->v[a]!=NULL) a++;
    }
    
    no->v[a]= (RayFace*) RE_rayobject_align(face);
    
    if(quad)
        calc_ocval_face(rtf[0], rtf[1], rtf[2], rtf[3], x>>2, y>>1, z, &no->ov[a]);
    else
        calc_ocval_face(rtf[0], rtf[1], rtf[2], NULL, x>>2, y>>1, z, &no->ov[a]);
}

static void d2dda(Octree *oc, short b1, short b2, short c1, short c2, char *ocface, short rts[][3], float rtf[][3])
{
    int ocx1,ocx2,ocy1,ocy2;
    int x,y,dx=0,dy=0;
    float ox1,ox2,oy1,oy2;
    float labda,labdao,labdax,labday,ldx,ldy;

    ocx1= rts[b1][c1];
    ocy1= rts[b1][c2];
    ocx2= rts[b2][c1];
    ocy2= rts[b2][c2];

    if(ocx1==ocx2 && ocy1==ocy2) {
        ocface[oc->ocres*ocx1+ocy1]= 1;
        return;
    }

    ox1= rtf[b1][c1];
    oy1= rtf[b1][c2];
    ox2= rtf[b2][c1];
    oy2= rtf[b2][c2];

    if(ox1!=ox2) {
        if(ox2-ox1>0.0f) {
            labdax= (ox1-ocx1-1.0f)/(ox1-ox2);
            ldx= -1.0f/(ox1-ox2);
            dx= 1;
        } else {
            labdax= (ox1-ocx1)/(ox1-ox2);
            ldx= 1.0f/(ox1-ox2);
            dx= -1;
        }
    } else {
        labdax=1.0f;
        ldx=0;
    }

    if(oy1!=oy2) {
        if(oy2-oy1>0.0f) {
            labday= (oy1-ocy1-1.0f)/(oy1-oy2);
            ldy= -1.0f/(oy1-oy2);
            dy= 1;
        } else {
            labday= (oy1-ocy1)/(oy1-oy2);
            ldy= 1.0f/(oy1-oy2);
            dy= -1;
        }
    } else {
        labday=1.0f;
        ldy=0;
    }
    
    x=ocx1; y=ocy1;
    labda= MIN2(labdax, labday);
    
    while(TRUE) {
        
        if(x<0 || y<0 || x>=oc->ocres || y>=oc->ocres);
        else ocface[oc->ocres*x+y]= 1;
        
        labdao=labda;
        if(labdax==labday) {
            labdax+=ldx;
            x+=dx;
            labday+=ldy;
            y+=dy;
        } else {
            if(labdax<labday) {
                labdax+=ldx;
                x+=dx;
            } else {
                labday+=ldy;
                y+=dy;
            }
        }
        labda=MIN2(labdax,labday);
        if(labda==labdao) break;
        if(labda>=1.0f) break;
    }
    ocface[oc->ocres*ocx2+ocy2]=1;
}

static void filltriangle(Octree *oc, short c1, short c2, char *ocface, short *ocmin, short *ocmax)
{
    int a, x, y, y1, y2;

    for(x=ocmin[c1];x<=ocmax[c1];x++) {
        a= oc->ocres*x;
        for(y=ocmin[c2];y<=ocmax[c2];y++) {
            if(ocface[a+y]) {
                y++;
                while(ocface[a+y] && y!=ocmax[c2]) y++;
                for(y1=ocmax[c2];y1>y;y1--) {
                    if(ocface[a+y1]) {
                        for(y2=y;y2<=y1;y2++) ocface[a+y2]=1;
                        y1=0;
                    }
                }
                y=ocmax[c2];
            }
        }
    }
}

static void RE_rayobject_octree_free(RayObject *tree)
{
    Octree *oc= (Octree*)tree;

#if 0
    printf("branches %d nodes %d\n", oc->branchcount, oc->nodecount);
    printf("raycount %d \n", raycount); 
    printf("ray coherent %d \n", coherent_ray);
    printf("accepted %d rejected %d\n", accepted, rejected);
#endif
    if(oc->ocface)
        MEM_freeN(oc->ocface);

    if(oc->adrbranch) {
        int a= 0;
        while(oc->adrbranch[a]) {
            MEM_freeN(oc->adrbranch[a]);
            oc->adrbranch[a]= NULL;
            a++;
        }
        MEM_freeN(oc->adrbranch);
        oc->adrbranch= NULL;
    }
    oc->branchcount= 0;
    
    if(oc->adrnode) {
        int a= 0;
        while(oc->adrnode[a]) {
            MEM_freeN(oc->adrnode[a]);
            oc->adrnode[a]= NULL;
            a++;
        }
        MEM_freeN(oc->adrnode);
        oc->adrnode= NULL;
    }
    oc->nodecount= 0;

    MEM_freeN(oc);
}


RayObject *RE_rayobject_octree_create(int ocres, int size)
{
    Octree *oc= (Octree*)MEM_callocN(sizeof(Octree), "Octree");
    assert( RE_rayobject_isAligned(oc) ); /* RayObject API assumes real data to be 4-byte aligned */    
    
    oc->rayobj.api = &octree_api;
    
    oc->ocres = ocres;
    
    oc->ro_nodes = (RayFace**)MEM_callocN(sizeof(RayFace*)*size, "octree rayobject nodes");
    oc->ro_nodes_size = size;
    oc->ro_nodes_used = 0;

    
    return RE_rayobject_unalignRayAPI((RayObject*) oc);
}


static void RE_rayobject_octree_add(RayObject *tree, RayObject *node)
{
    Octree *oc = (Octree*)tree;

    assert( RE_rayobject_isRayFace(node) );
    assert( oc->ro_nodes_used < oc->ro_nodes_size );
    oc->ro_nodes[ oc->ro_nodes_used++ ] = (RayFace*)RE_rayobject_align(node);
}

static void octree_fill_rayface(Octree *oc, RayFace *face)
{
    float ocfac[3], rtf[4][3];
    float co1[3], co2[3], co3[3], co4[3];
    short rts[4][3];
    short ocmin[3], ocmax[3];
    char *ocface= oc->ocface;   // front, top, size view of face, to fill in
    int a, b, c, oc1, oc2, oc3, oc4, x, y, z, ocres2;

    ocfac[0]= oc->ocfacx;
    ocfac[1]= oc->ocfacy;
    ocfac[2]= oc->ocfacz;

    ocres2= oc->ocres*oc->ocres;

    copy_v3_v3(co1, face->v1);
    copy_v3_v3(co2, face->v2);
    copy_v3_v3(co3, face->v3);
    if(face->v4)
        copy_v3_v3(co4, face->v4);

    for(c=0;c<3;c++) {
        rtf[0][c]= (co1[c]-oc->min[c])*ocfac[c] ;
        rts[0][c]= (short)rtf[0][c];
        rtf[1][c]= (co2[c]-oc->min[c])*ocfac[c] ;
        rts[1][c]= (short)rtf[1][c];
        rtf[2][c]= (co3[c]-oc->min[c])*ocfac[c] ;
        rts[2][c]= (short)rtf[2][c];
        if(RE_rayface_isQuad(face)) {
            rtf[3][c]= (co4[c]-oc->min[c])*ocfac[c] ;
            rts[3][c]= (short)rtf[3][c];
        }
    }
    
    for(c=0;c<3;c++) {
        oc1= rts[0][c];
        oc2= rts[1][c];
        oc3= rts[2][c];
        if(!RE_rayface_isQuad(face)) {
            ocmin[c]= MIN3(oc1,oc2,oc3);
            ocmax[c]= MAX3(oc1,oc2,oc3);
        }
        else {
            oc4= rts[3][c];
            ocmin[c]= MIN4(oc1,oc2,oc3,oc4);
            ocmax[c]= MAX4(oc1,oc2,oc3,oc4);
        }
        if(ocmax[c]>oc->ocres-1) ocmax[c]=oc->ocres-1;
        if(ocmin[c]<0) ocmin[c]=0;
    }
    
    if(ocmin[0]==ocmax[0] && ocmin[1]==ocmax[1] && ocmin[2]==ocmax[2]) {
        ocwrite(oc, face, RE_rayface_isQuad(face), ocmin[0], ocmin[1], ocmin[2], rtf);
    }
    else {
        
        d2dda(oc, 0,1,0,1,ocface+ocres2,rts,rtf);
        d2dda(oc, 0,1,0,2,ocface,rts,rtf);
        d2dda(oc, 0,1,1,2,ocface+2*ocres2,rts,rtf);
        d2dda(oc, 1,2,0,1,ocface+ocres2,rts,rtf);
        d2dda(oc, 1,2,0,2,ocface,rts,rtf);
        d2dda(oc, 1,2,1,2,ocface+2*ocres2,rts,rtf);
        if(!RE_rayface_isQuad(face)) {
            d2dda(oc, 2,0,0,1,ocface+ocres2,rts,rtf);
            d2dda(oc, 2,0,0,2,ocface,rts,rtf);
            d2dda(oc, 2,0,1,2,ocface+2*ocres2,rts,rtf);
        }
        else {
            d2dda(oc, 2,3,0,1,ocface+ocres2,rts,rtf);
            d2dda(oc, 2,3,0,2,ocface,rts,rtf);
            d2dda(oc, 2,3,1,2,ocface+2*ocres2,rts,rtf);
            d2dda(oc, 3,0,0,1,ocface+ocres2,rts,rtf);
            d2dda(oc, 3,0,0,2,ocface,rts,rtf);
            d2dda(oc, 3,0,1,2,ocface+2*ocres2,rts,rtf);
        }
        /* nothing todo with triangle..., just fills :) */
        filltriangle(oc, 0,1,ocface+ocres2,ocmin,ocmax);
        filltriangle(oc, 0,2,ocface,ocmin,ocmax);
        filltriangle(oc, 1,2,ocface+2*ocres2,ocmin,ocmax);
        
        /* init static vars here */
        face_in_node(face, 0,0,0, rtf);
        
        for(x=ocmin[0];x<=ocmax[0];x++) {
            a= oc->ocres*x;
            for(y=ocmin[1];y<=ocmax[1];y++) {
                if(ocface[a+y+ocres2]) {
                    b= oc->ocres*y+2*ocres2;
                    for(z=ocmin[2];z<=ocmax[2];z++) {
                        if(ocface[b+z] && ocface[a+z]) {
                            if(face_in_node(NULL, x, y, z, rtf))
                                ocwrite(oc, face, RE_rayface_isQuad(face), x,y,z, rtf);
                        }
                    }
                }
            }
        }
        
        /* same loops to clear octree, doubt it can be done smarter */
        for(x=ocmin[0];x<=ocmax[0];x++) {
            a= oc->ocres*x;
            for(y=ocmin[1];y<=ocmax[1];y++) {
                /* x-y */
                ocface[a+y+ocres2]= 0;

                b= oc->ocres*y + 2*ocres2;
                for(z=ocmin[2];z<=ocmax[2];z++) {
                    /* y-z */
                    ocface[b+z]= 0;
                    /* x-z */
                    ocface[a+z]= 0;
                }
            }
        }
    }
}

static void RE_rayobject_octree_done(RayObject *tree)
{
    Octree *oc = (Octree*)tree;
    int c;
    float t00, t01, t02;
    int ocres2 = oc->ocres*oc->ocres;
    
    INIT_MINMAX(oc->min, oc->max);
    
    /* Calculate Bounding Box */
    for(c=0; c<oc->ro_nodes_used; c++)
        RE_rayobject_merge_bb( RE_rayobject_unalignRayFace(oc->ro_nodes[c]), oc->min, oc->max);
        
    /* Alloc memory */
    oc->adrbranch= (Branch**)MEM_callocN(sizeof(void *)*BRANCH_ARRAY, "octree branches");
    oc->adrnode= (Node**)MEM_callocN(sizeof(void *)*NODE_ARRAY, "octree nodes");
    
    oc->adrbranch[0]=(Branch *)MEM_callocN(4096*sizeof(Branch), "makeoctree");
    
    /* the lookup table, per face, for which nodes to fill in */
    oc->ocface= (char*)MEM_callocN( 3*ocres2 + 8, "ocface");
    memset(oc->ocface, 0, 3*ocres2);

    for(c=0;c<3;c++) {  /* octree enlarge, still needed? */
        oc->min[c]-= 0.01f;
        oc->max[c]+= 0.01f;
    }

    t00= oc->max[0]-oc->min[0];
    t01= oc->max[1]-oc->min[1];
    t02= oc->max[2]-oc->min[2];
    
    /* this minus 0.1 is old safety... seems to be needed? */
    oc->ocfacx= (oc->ocres-0.1)/t00;
    oc->ocfacy= (oc->ocres-0.1)/t01;
    oc->ocfacz= (oc->ocres-0.1)/t02;
    
    oc->ocsize= sqrt(t00*t00+t01*t01+t02*t02);  /* global, max size octree */

    for(c=0; c<oc->ro_nodes_used; c++)
    {
        octree_fill_rayface(oc, oc->ro_nodes[c]);
    }

    MEM_freeN(oc->ocface);
    oc->ocface = NULL;
    MEM_freeN(oc->ro_nodes);
    oc->ro_nodes = NULL;
    
    printf("%f %f - %f\n", oc->min[0], oc->max[0], oc->ocfacx );
    printf("%f %f - %f\n", oc->min[1], oc->max[1], oc->ocfacy );
    printf("%f %f - %f\n", oc->min[2], oc->max[2], oc->ocfacz );
}

static void RE_rayobject_octree_bb(RayObject *tree, float *min, float *max)
{
    Octree *oc = (Octree*)tree;
    DO_MINMAX(oc->min, min, max);
    DO_MINMAX(oc->max, min, max);
}

/* check all faces in this node */
static int testnode(Octree *UNUSED(oc), Isect *is, Node *no, OcVal ocval)
{
    short nr=0;

    /* return on any first hit */
    if(is->mode==RE_RAY_SHADOW) {
    
        for(; no; no = no->next)
        for(nr=0; nr<8; nr++)
        {
            RayFace *face = no->v[nr];
            OcVal       *ov = no->ov+nr;
            
            if(!face) break;
            
            if( (ov->ocx & ocval.ocx) && (ov->ocy & ocval.ocy) && (ov->ocz & ocval.ocz) )
            {
                if( RE_rayobject_intersect( RE_rayobject_unalignRayFace(face),is) )
                    return 1;
            }
        }
    }
    else
    {           /* else mirror or glass or shadowtra, return closest face  */
        int found= 0;
        
        for(; no; no = no->next)
        for(nr=0; nr<8; nr++)
        {
            RayFace *face = no->v[nr];
            OcVal       *ov = no->ov+nr;
            
            if(!face) break;
            
            if( (ov->ocx & ocval.ocx) && (ov->ocy & ocval.ocy) && (ov->ocz & ocval.ocz) )
            { 
                if( RE_rayobject_intersect( RE_rayobject_unalignRayFace(face),is) )
                    found= 1;
            }
        }
        
        return found;
    }

    return 0;
}

/* find the Node for the octree coord x y z */
static Node *ocread(Octree *oc, int x, int y, int z)
{
    Branch *br;
    int oc1;
    
    x<<=2;
    y<<=1;
    
    br= oc->adrbranch[0];
    
    if(oc->ocres==512) {
        oc1= ((x & 1024)+(y & 512)+(z & 256))>>8;
        br= br->b[oc1];
        if(br==NULL) {
            return NULL;
        }
    }
    if(oc->ocres>=256) {
        oc1= ((x & 512)+(y & 256)+(z & 128))>>7;
        br= br->b[oc1];
        if(br==NULL) {
            return NULL;
        }
    }
    if(oc->ocres>=128) {
        oc1= ((x & 256)+(y & 128)+(z & 64))>>6;
        br= br->b[oc1];
        if(br==NULL) {
            return NULL;
        }
    }
    
    oc1= ((x & 128)+(y & 64)+(z & 32))>>5;
    br= br->b[oc1];
    if(br) {
        oc1= ((x & 64)+(y & 32)+(z & 16))>>4;
        br= br->b[oc1];
        if(br) {
            oc1= ((x & 32)+(y & 16)+(z & 8))>>3;
            br= br->b[oc1];
            if(br) {
                oc1= ((x & 16)+(y & 8)+(z & 4))>>2;
                br= br->b[oc1];
                if(br) {
                    oc1= ((x & 8)+(y & 4)+(z & 2))>>1;
                    br= br->b[oc1];
                    if(br) {
                        oc1= ((x & 4)+(y & 2)+(z & 1));
                        return (Node *)br->b[oc1];
                    }
                }
            }
        }
    }
    
    return NULL;
}

static int cliptest(float p, float q, float *u1, float *u2)
{
    float r;

    if(p<0.0f) {
        if(q<p) return 0;
        else if(q<0.0f) {
            r= q/p;
            if(r>*u2) return 0;
            else if(r>*u1) *u1=r;
        }
    }
    else {
        if(p>0.0f) {
            if(q<0.0f) return 0;
            else if(q<p) {
                r= q/p;
                if(r<*u1) return 0;
                else if(r<*u2) *u2=r;
            }
        }
        else if(q<0.0f) return 0;
    }
    return 1;
}

/* extensive coherence checks/storage cancels out the benefit of it, and gives errors... we
   need better methods, sample code commented out below (ton) */
 
/*

in top: static int coh_nodes[16*16*16][6];
in makeoctree: memset(coh_nodes, 0, sizeof(coh_nodes));
 
static void add_coherence_test(int ocx1, int ocx2, int ocy1, int ocy2, int ocz1, int ocz2)
{
    short *sp;
    
    sp= coh_nodes[ (ocx2 & 15) + 16*(ocy2 & 15) + 256*(ocz2 & 15) ];
    sp[0]= ocx1; sp[1]= ocy1; sp[2]= ocz1;
    sp[3]= ocx2; sp[4]= ocy2; sp[5]= ocz2;
    
}

static int do_coherence_test(int ocx1, int ocx2, int ocy1, int ocy2, int ocz1, int ocz2)
{
    short *sp;
    
    sp= coh_nodes[ (ocx2 & 15) + 16*(ocy2 & 15) + 256*(ocz2 & 15) ];
    if(sp[0]==ocx1 && sp[1]==ocy1 && sp[2]==ocz1 &&
       sp[3]==ocx2 && sp[4]==ocy2 && sp[5]==ocz2) return 1;
    return 0;
}

*/

/* return 1: found valid intersection */
/* starts with is->orig.face */
static int RE_rayobject_octree_intersect(RayObject *tree, Isect *is)
{
    Octree *oc= (Octree*)tree;
    Node *no;
    OcVal ocval;
    float vec1[3], vec2[3], start[3], end[3];
    float u1,u2,ox1,ox2,oy1,oy2,oz1,oz2;
    float labdao,labdax,ldx,labday,ldy,labdaz,ldz, ddalabda;
    float olabda = 0;
    int dx,dy,dz;   
    int xo,yo,zo,c1=0;
    int ocx1,ocx2,ocy1, ocy2,ocz1,ocz2;
    
    /* clip with octree */
    if(oc->branchcount==0) return 0;
    
    /* do this before intersect calls */
#if 0
    is->facecontr= NULL;                /* to check shared edge */
    is->obcontr= 0;
    is->faceisect= is->isect= 0;        /* shared edge, quad half flag */
    is->userdata= oc->userdata;
#endif

    copy_v3_v3( start, is->start );
    madd_v3_v3v3fl( end, is->start, is->dir, is->dist );
    ldx= is->dir[0]*is->dist;
    olabda = is->dist;
    u1= 0.0f;
    u2= 1.0f;
    
    /* clip with octree cube */
    if(cliptest(-ldx, start[0]-oc->min[0], &u1,&u2)) {
        if(cliptest(ldx, oc->max[0]-start[0], &u1,&u2)) {
            ldy= is->dir[1]*is->dist;
            if(cliptest(-ldy, start[1]-oc->min[1], &u1,&u2)) {
                if(cliptest(ldy, oc->max[1]-start[1], &u1,&u2)) {
                    ldz = is->dir[2]*is->dist;
                    if(cliptest(-ldz, start[2]-oc->min[2], &u1,&u2)) {
                        if(cliptest(ldz, oc->max[2]-start[2], &u1,&u2)) {
                            c1=1;
                            if(u2<1.0f) {
                                end[0] = start[0]+u2*ldx;
                                end[1] = start[1]+u2*ldy;
                                end[2] = start[2]+u2*ldz;
                            }

                            if(u1>0.0f) {
                                start[0] += u1*ldx;
                                start[1] += u1*ldy;
                                start[2] += u1*ldz;
                            }
                        }
                    }
                }
            }
        }
    }

    if(c1==0) return 0;

    /* reset static variables in ocread */
    //ocread(oc, oc->ocres, 0, 0);

    /* setup 3dda to traverse octree */
    ox1= (start[0]-oc->min[0])*oc->ocfacx;
    oy1= (start[1]-oc->min[1])*oc->ocfacy;
    oz1= (start[2]-oc->min[2])*oc->ocfacz;
    ox2= (end[0]-oc->min[0])*oc->ocfacx;
    oy2= (end[1]-oc->min[1])*oc->ocfacy;
    oz2= (end[2]-oc->min[2])*oc->ocfacz;

    ocx1= (int)ox1;
    ocy1= (int)oy1;
    ocz1= (int)oz1;
    ocx2= (int)ox2;
    ocy2= (int)oy2;
    ocz2= (int)oz2;
    
    if(ocx1==ocx2 && ocy1==ocy2 && ocz1==ocz2) {
        no= ocread(oc, ocx1, ocy1, ocz1);
        if(no) {
            /* exact intersection with node */
            vec1[0]= ox1; vec1[1]= oy1; vec1[2]= oz1;
            vec2[0]= ox2; vec2[1]= oy2; vec2[2]= oz2;
            calc_ocval_ray(&ocval, (float)ocx1, (float)ocy1, (float)ocz1, vec1, vec2);
            if( testnode(oc, is, no, ocval) ) return 1;
        }
    }
    else {
        int found = 0;
        //static int coh_ocx1,coh_ocx2,coh_ocy1, coh_ocy2,coh_ocz1,coh_ocz2;
        float dox, doy, doz;
        int eqval;
        
        /* calc labda en ld */
        dox= ox1-ox2;
        doy= oy1-oy2;
        doz= oz1-oz2;

        if(dox<-FLT_EPSILON) {
            ldx= -1.0f/dox;
            labdax= (ocx1-ox1+1.0f)*ldx;
            dx= 1;
        } else if(dox>FLT_EPSILON) {
            ldx= 1.0f/dox;
            labdax= (ox1-ocx1)*ldx;
            dx= -1;
        } else {
            labdax=1.0f;
            ldx=0;
            dx= 0;
        }

        if(doy<-FLT_EPSILON) {
            ldy= -1.0f/doy;
            labday= (ocy1-oy1+1.0f)*ldy;
            dy= 1;
        } else if(doy>FLT_EPSILON) {
            ldy= 1.0f/doy;
            labday= (oy1-ocy1)*ldy;
            dy= -1;
        } else {
            labday=1.0f;
            ldy=0;
            dy= 0;
        }

        if(doz<-FLT_EPSILON) {
            ldz= -1.0f/doz;
            labdaz= (ocz1-oz1+1.0f)*ldz;
            dz= 1;
        } else if(doz>FLT_EPSILON) {
            ldz= 1.0f/doz;
            labdaz= (oz1-ocz1)*ldz;
            dz= -1;
        } else {
            labdaz=1.0f;
            ldz=0;
            dz= 0;
        }
        
        xo=ocx1; yo=ocy1; zo=ocz1;
        ddalabda= MIN3(labdax,labday,labdaz);
        
        vec2[0]= ox1;
        vec2[1]= oy1;
        vec2[2]= oz1;
        
        /* this loop has been constructed to make sure the first and last node of ray
           are always included, even when ddalabda==1.0f or larger */

        while(TRUE) {

            no= ocread(oc, xo, yo, zo);
            if(no) {
                
                /* calculate ray intersection with octree node */
                copy_v3_v3(vec1, vec2);
                // dox,y,z is negative
                vec2[0]= ox1-ddalabda*dox;
                vec2[1]= oy1-ddalabda*doy;
                vec2[2]= oz1-ddalabda*doz;
                calc_ocval_ray(&ocval, (float)xo, (float)yo, (float)zo, vec1, vec2);

                //is->dist = (u1+ddalabda*(u2-u1))*olabda;
                if( testnode(oc, is, no, ocval) )
                    found = 1;

                if(is->dist < (u1+ddalabda*(u2-u1))*olabda)
                    return found;
            }


            labdao= ddalabda;
            
            /* traversing ocree nodes need careful detection of smallest values, with proper
               exceptions for equal labdas */
            eqval= (labdax==labday);
            if(labday==labdaz) eqval += 2;
            if(labdax==labdaz) eqval += 4;
            
            if(eqval) { // only 4 cases exist!
                if(eqval==7) {  // x=y=z
                    xo+=dx; labdax+=ldx;
                    yo+=dy; labday+=ldy;
                    zo+=dz; labdaz+=ldz;
                }
                else if(eqval==1) { // x=y 
                    if(labday < labdaz) {
                        xo+=dx; labdax+=ldx;
                        yo+=dy; labday+=ldy;
                    }
                    else {
                        zo+=dz; labdaz+=ldz;
                    }
                }
                else if(eqval==2) { // y=z
                    if(labdax < labday) {
                        xo+=dx; labdax+=ldx;
                    }
                    else {
                        yo+=dy; labday+=ldy;
                        zo+=dz; labdaz+=ldz;
                    }
                }
                else { // x=z
                    if(labday < labdax) {
                        yo+=dy; labday+=ldy;
                    }
                    else {
                        xo+=dx; labdax+=ldx;
                        zo+=dz; labdaz+=ldz;
                    }
                }
            }
            else {  // all three different, just three cases exist
                eqval= (labdax<labday);
                if(labday<labdaz) eqval += 2;
                if(labdax<labdaz) eqval += 4;
                
                if(eqval==7 || eqval==5) { // x smallest
                    xo+=dx; labdax+=ldx;
                }
                else if(eqval==2 || eqval==6) { // y smallest
                    yo+=dy; labday+=ldy;
                }
                else { // z smallest
                    zo+=dz; labdaz+=ldz;
                }
                
            }

            ddalabda=MIN3(labdax,labday,labdaz);
            if(ddalabda==labdao) break;
            /* to make sure the last node is always checked */
            if(labdao>=1.0f) break;
        }
    }
    
    /* reached end, no intersections found */
    return 0;
}