imagetexture.c

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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) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * Contributors: 2004/2005/2006 Blender Foundation, full recode
 *
 * ***** END GPL/BL DUAL LICENSE BLOCK *****
 */

#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <math.h>
#include <float.h>
#ifndef WIN32 
#include <unistd.h>
#else
#include <io.h>
#endif

#include "MEM_guardedalloc.h"

#include "IMB_imbuf_types.h"
#include "IMB_imbuf.h"

#include "DNA_image_types.h"
#include "DNA_scene_types.h"
#include "DNA_texture_types.h"

#include "BLI_math.h"
#include "BLI_blenlib.h"
#include "BLI_threads.h"
#include "BLI_utildefines.h"

#include "BKE_global.h"
#include "BKE_main.h"
#include "BKE_image.h"
#include "BKE_texture.h"
#include "BKE_library.h"

#include "RE_render_ext.h"

#include "renderpipeline.h"
#include "render_types.h"
#include "texture.h"

/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
/* defined in pipeline.c, is hardcopy of active dynamic allocated Render */
/* only to be used here in this file, it's for speed */
extern struct Render R;
/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */

static void boxsample(ImBuf *ibuf, float minx, float miny, float maxx, float maxy, TexResult *texres, const short imaprepeat, const short imapextend);

/* *********** IMAGEWRAPPING ****************** */


/* x and y have to be checked for image size */
static void ibuf_get_color(float *col, struct ImBuf *ibuf, int x, int y)
{
    int ofs = y * ibuf->x + x;
    
    if(ibuf->rect_float) {
        if(ibuf->channels==4) {
            float *fp= ibuf->rect_float + 4*ofs;
            copy_v4_v4(col, fp);
        }
        else if(ibuf->channels==3) {
            float *fp= ibuf->rect_float + 3*ofs;
            copy_v3_v3(col, fp);
            col[3]= 1.0f;
        }
        else {
            float *fp= ibuf->rect_float + ofs;
            col[0]= col[1]= col[2]= col[3]= *fp;
        }
    }
    else {
        char *rect = (char *)( ibuf->rect+ ofs);

        col[0] = ((float)rect[0])*(1.0f/255.0f);
        col[1] = ((float)rect[1])*(1.0f/255.0f);
        col[2] = ((float)rect[2])*(1.0f/255.0f);
        col[3] = ((float)rect[3])*(1.0f/255.0f);
    }   
}

int imagewrap(Tex *tex, Image *ima, ImBuf *ibuf, const float texvec[3], TexResult *texres)
{
    float fx, fy, val1, val2, val3;
    int x, y, retval;
    int xi, yi; /* original values */

    texres->tin= texres->ta= texres->tr= texres->tg= texres->tb= 0.0f;
    
    /* we need to set retval OK, otherwise texture code generates normals itself... */
    retval= texres->nor?3:1;
    
    /* quick tests */
    if(ibuf==NULL && ima==NULL)
        return retval;
    if(ima) {
        
        /* hack for icon render */
        if(ima->ibufs.first==NULL && (R.r.scemode & R_NO_IMAGE_LOAD))
            return retval;
        
        ibuf= BKE_image_get_ibuf(ima, &tex->iuser);
    }
    if(ibuf==NULL || (ibuf->rect==NULL && ibuf->rect_float==NULL))
        return retval;
    
    /* setup mapping */
    if(tex->imaflag & TEX_IMAROT) {
        fy= texvec[0];
        fx= texvec[1];
    }
    else {
        fx= texvec[0];
        fy= texvec[1];
    }
    
    if(tex->extend == TEX_CHECKER) {
        int xs, ys;
        
        xs= (int)floor(fx);
        ys= (int)floor(fy);
        fx-= xs;
        fy-= ys;

        if( (tex->flag & TEX_CHECKER_ODD)==0) {
            if((xs+ys) & 1);else return retval;
        }
        if( (tex->flag & TEX_CHECKER_EVEN)==0) {
            if((xs+ys) & 1) return retval; 
        }
        /* scale around center, (0.5, 0.5) */
        if(tex->checkerdist<1.0f) {
            fx= (fx-0.5f)/(1.0f-tex->checkerdist) +0.5f;
            fy= (fy-0.5f)/(1.0f-tex->checkerdist) +0.5f;
        }
    }

    x= xi= (int)floorf(fx*ibuf->x);
    y= yi= (int)floorf(fy*ibuf->y);

    if(tex->extend == TEX_CLIPCUBE) {
        if(x<0 || y<0 || x>=ibuf->x || y>=ibuf->y || texvec[2]<-1.0f || texvec[2]>1.0f) {
            return retval;
        }
    }
    else if( tex->extend==TEX_CLIP || tex->extend==TEX_CHECKER) {
        if(x<0 || y<0 || x>=ibuf->x || y>=ibuf->y) {
            return retval;
        }
    }
    else {
        if(tex->extend==TEX_EXTEND) {
            if(x>=ibuf->x) x = ibuf->x-1;
            else if(x<0) x= 0;
        }
        else {
            x= x % ibuf->x;
            if(x<0) x+= ibuf->x;
        }
        if(tex->extend==TEX_EXTEND) {
            if(y>=ibuf->y) y = ibuf->y-1;
            else if(y<0) y= 0;
        }
        else {
            y= y % ibuf->y;
            if(y<0) y+= ibuf->y;
        }
    }
    
    /* warning, no return before setting back! */
    if( (R.flag & R_SEC_FIELD) && (ibuf->flags & IB_fields) ) {
        ibuf->rect+= (ibuf->x*ibuf->y);
    }

    /* keep this before interpolation [#29761] */
    if (tex->imaflag & TEX_USEALPHA) {
        if ((tex->imaflag & TEX_CALCALPHA) == 0) {
            texres->talpha = TRUE;
        } 
    }

    /* interpolate */
    if (tex->imaflag & TEX_INTERPOL) {
        float filterx, filtery;
        filterx = (0.5f * tex->filtersize) / ibuf->x;
        filtery = (0.5f * tex->filtersize) / ibuf->y;

        /* important that this value is wrapped [#27782]
         * this applies the modifications made by the checks above,
         * back to the floating point values */
        fx -= (float)(xi - x) / (float)ibuf->x;
        fy -= (float)(yi - y) / (float)ibuf->y;

        boxsample(ibuf, fx-filterx, fy-filtery, fx+filterx, fy+filtery, texres, (tex->extend==TEX_REPEAT), (tex->extend==TEX_EXTEND));
    }
    else { /* no filtering */
        ibuf_get_color(&texres->tr, ibuf, x, y);
    }
    
    if( (R.flag & R_SEC_FIELD) && (ibuf->flags & IB_fields) ) {
        ibuf->rect-= (ibuf->x*ibuf->y);
    }

    if(texres->nor) {
        if(tex->imaflag & TEX_NORMALMAP) {
            // qdn: normal from color
            // The invert of the red channel is to make
            // the normal map compliant with the outside world.
            // It needs to be done because in Blender
            // the normal used in the renderer points inward. It is generated
            // this way in calc_vertexnormals(). Should this ever change
            // this negate must be removed.
            texres->nor[0] = -2.f*(texres->tr - 0.5f);
            texres->nor[1] = 2.f*(texres->tg - 0.5f);
            texres->nor[2] = 2.f*(texres->tb - 0.5f);
        }
        else {
            /* bump: take three samples */
            val1= texres->tr+texres->tg+texres->tb;

            if(x<ibuf->x-1) {
                float col[4];
                ibuf_get_color(col, ibuf, x+1, y);
                val2= (col[0]+col[1]+col[2]);
            }
            else val2= val1;

            if(y<ibuf->y-1) {
                float col[4];
                ibuf_get_color(col, ibuf, x, y+1);
                val3= (col[0]+col[1]+col[2]);
            }
            else val3= val1;

            /* do not mix up x and y here! */
            texres->nor[0]= (val1-val2);
            texres->nor[1]= (val1-val3);
        }
    }

    if(texres->talpha) texres->tin= texres->ta;
    else if(tex->imaflag & TEX_CALCALPHA) {
        texres->ta= texres->tin= MAX3(texres->tr, texres->tg, texres->tb);
    }
    else texres->ta= texres->tin= 1.0;
    
    if(tex->flag & TEX_NEGALPHA) texres->ta= 1.0f-texres->ta;

    /* de-premul, this is being premulled in shade_input_do_shade() */
    if(texres->ta!=1.0f && texres->ta>1e-4f) {
        fx= 1.0f/texres->ta;
        texres->tr*= fx;
        texres->tg*= fx;
        texres->tb*= fx;
    }
    
    BRICONTRGB;
    
    return retval;
}

static void clipx_rctf_swap(rctf *stack, short *count, float x1, float x2)
{
    rctf *rf, *newrct;
    short a;

    a= *count;
    rf= stack;
    for(;a>0;a--) {
        if(rf->xmin<x1) {
            if(rf->xmax<x1) {
                rf->xmin+= (x2-x1);
                rf->xmax+= (x2-x1);
            }
            else {
                if(rf->xmax>x2) rf->xmax= x2;
                newrct= stack+ *count;
                (*count)++;

                newrct->xmax= x2;
                newrct->xmin= rf->xmin+(x2-x1);
                newrct->ymin= rf->ymin;
                newrct->ymax= rf->ymax;
                
                if(newrct->xmin==newrct->xmax) (*count)--;
                
                rf->xmin= x1;
            }
        }
        else if(rf->xmax>x2) {
            if(rf->xmin>x2) {
                rf->xmin-= (x2-x1);
                rf->xmax-= (x2-x1);
            }
            else {
                if(rf->xmin<x1) rf->xmin= x1;
                newrct= stack+ *count;
                (*count)++;

                newrct->xmin= x1;
                newrct->xmax= rf->xmax-(x2-x1);
                newrct->ymin= rf->ymin;
                newrct->ymax= rf->ymax;

                if(newrct->xmin==newrct->xmax) (*count)--;

                rf->xmax= x2;
            }
        }
        rf++;
    }

}

static void clipy_rctf_swap(rctf *stack, short *count, float y1, float y2)
{
    rctf *rf, *newrct;
    short a;

    a= *count;
    rf= stack;
    for(;a>0;a--) {
        if(rf->ymin<y1) {
            if(rf->ymax<y1) {
                rf->ymin+= (y2-y1);
                rf->ymax+= (y2-y1);
            }
            else {
                if(rf->ymax>y2) rf->ymax= y2;
                newrct= stack+ *count;
                (*count)++;

                newrct->ymax= y2;
                newrct->ymin= rf->ymin+(y2-y1);
                newrct->xmin= rf->xmin;
                newrct->xmax= rf->xmax;

                if(newrct->ymin==newrct->ymax) (*count)--;

                rf->ymin= y1;
            }
        }
        else if(rf->ymax>y2) {
            if(rf->ymin>y2) {
                rf->ymin-= (y2-y1);
                rf->ymax-= (y2-y1);
            }
            else {
                if(rf->ymin<y1) rf->ymin= y1;
                newrct= stack+ *count;
                (*count)++;

                newrct->ymin= y1;
                newrct->ymax= rf->ymax-(y2-y1);
                newrct->xmin= rf->xmin;
                newrct->xmax= rf->xmax;

                if(newrct->ymin==newrct->ymax) (*count)--;

                rf->ymax= y2;
            }
        }
        rf++;
    }
}

static float square_rctf(rctf *rf)
{
    float x, y;

    x= rf->xmax- rf->xmin;
    y= rf->ymax- rf->ymin;
    return (x*y);
}

static float clipx_rctf(rctf *rf, float x1, float x2)
{
    float size;

    size= rf->xmax - rf->xmin;

    if(rf->xmin<x1) {
        rf->xmin= x1;
    }
    if(rf->xmax>x2) {
        rf->xmax= x2;
    }
    if(rf->xmin > rf->xmax) {
        rf->xmin = rf->xmax;
        return 0.0;
    }
    else if(size!=0.0f) {
        return (rf->xmax - rf->xmin)/size;
    }
    return 1.0;
}

static float clipy_rctf(rctf *rf, float y1, float y2)
{
    float size;

    size= rf->ymax - rf->ymin;

    if(rf->ymin<y1) {
        rf->ymin= y1;
    }
    if(rf->ymax>y2) {
        rf->ymax= y2;
    }

    if(rf->ymin > rf->ymax) {
        rf->ymin = rf->ymax;
        return 0.0;
    }
    else if(size!=0.0f) {
        return (rf->ymax - rf->ymin)/size;
    }
    return 1.0;

}

static void boxsampleclip(struct ImBuf *ibuf, rctf *rf, TexResult *texres)
{
    /* sample box, is clipped already, and minx etc. have been set at ibuf size.
       Enlarge with antialiased edges of the pixels */

    float muly, mulx, div, col[4];
    int x, y, startx, endx, starty, endy;

    startx= (int)floor(rf->xmin);
    endx= (int)floor(rf->xmax);
    starty= (int)floor(rf->ymin);
    endy= (int)floor(rf->ymax);

    if(startx < 0) startx= 0;
    if(starty < 0) starty= 0;
    if(endx>=ibuf->x) endx= ibuf->x-1;
    if(endy>=ibuf->y) endy= ibuf->y-1;

    if(starty==endy && startx==endx) {
        ibuf_get_color(&texres->tr, ibuf, startx, starty);
    }
    else {
        div= texres->tr= texres->tg= texres->tb= texres->ta= 0.0;
        for(y=starty; y<=endy; y++) {
            
            muly= 1.0;

            if(starty==endy);
            else {
                if(y==starty) muly= 1.0f-(rf->ymin - y);
                if(y==endy) muly= (rf->ymax - y);
            }
            
            if(startx==endx) {
                mulx= muly;
                
                ibuf_get_color(col, ibuf, startx, y);

                texres->ta+= mulx*col[3];
                texres->tr+= mulx*col[0];
                texres->tg+= mulx*col[1];
                texres->tb+= mulx*col[2];
                div+= mulx;
            }
            else {
                for(x=startx; x<=endx; x++) {
                    mulx= muly;
                    if(x==startx) mulx*= 1.0f-(rf->xmin - x);
                    if(x==endx) mulx*= (rf->xmax - x);

                    ibuf_get_color(col, ibuf, x, y);
                    
                    if(mulx==1.0f) {
                        texres->ta+= col[3];
                        texres->tr+= col[0];
                        texres->tg+= col[1];
                        texres->tb+= col[2];
                        div+= 1.0f;
                    }
                    else {
                        texres->ta+= mulx*col[3];
                        texres->tr+= mulx*col[0];
                        texres->tg+= mulx*col[1];
                        texres->tb+= mulx*col[2];
                        div+= mulx;
                    }
                }
            }
        }

        if(div!=0.0f) {
            div= 1.0f/div;
            texres->tb*= div;
            texres->tg*= div;
            texres->tr*= div;
            texres->ta*= div;
        }
        else {
            texres->tr= texres->tg= texres->tb= texres->ta= 0.0f;
        }
    }
}

static void boxsample(ImBuf *ibuf, float minx, float miny, float maxx, float maxy, TexResult *texres, const short imaprepeat, const short imapextend)
{
    /* Sample box, performs clip. minx etc are in range 0.0 - 1.0 .
     * Enlarge with antialiased edges of pixels.
     * If variable 'imaprepeat' has been set, the
     * clipped-away parts are sampled as well.
     */
    /* note: actually minx etc isnt in the proper range... this due to filter size and offset vectors for bump */
    /* note: talpha must be initialized */
    /* note: even when 'imaprepeat' is set, this can only repeate once in any direction.
     * the point which min/max is derived from is assumed to be wrapped */
    TexResult texr;
    rctf *rf, stack[8];
    float opp, tot, alphaclip= 1.0;
    short count=1;

    rf= stack;
    rf->xmin= minx*(ibuf->x);
    rf->xmax= maxx*(ibuf->x);
    rf->ymin= miny*(ibuf->y);
    rf->ymax= maxy*(ibuf->y);

    texr.talpha= texres->talpha;    /* is read by boxsample_clip */
    
    if(imapextend) {
        CLAMP(rf->xmin, 0.0f, ibuf->x-1);
        CLAMP(rf->xmax, 0.0f, ibuf->x-1);
    }
    else if(imaprepeat) 
        clipx_rctf_swap(stack, &count, 0.0, (float)(ibuf->x));
    else {
        alphaclip= clipx_rctf(rf, 0.0, (float)(ibuf->x));

        if(alphaclip<=0.0f) {
            texres->tr= texres->tb= texres->tg= texres->ta= 0.0;
            return;
        }
    }

    if(imapextend) {
        CLAMP(rf->ymin, 0.0f, ibuf->y-1);
        CLAMP(rf->ymax, 0.0f, ibuf->y-1);
    }
    else if(imaprepeat) 
        clipy_rctf_swap(stack, &count, 0.0, (float)(ibuf->y));
    else {
        alphaclip*= clipy_rctf(rf, 0.0, (float)(ibuf->y));

        if(alphaclip<=0.0f) {
            texres->tr= texres->tb= texres->tg= texres->ta= 0.0;
            return;
        }
    }

    if(count>1) {
        tot= texres->tr= texres->tb= texres->tg= texres->ta= 0.0;
        while(count--) {
            boxsampleclip(ibuf, rf, &texr);
            
            opp= square_rctf(rf);
            tot+= opp;

            texres->tr+= opp*texr.tr;
            texres->tg+= opp*texr.tg;
            texres->tb+= opp*texr.tb;
            if(texres->talpha) texres->ta+= opp*texr.ta;
            rf++;
        }
        if(tot!= 0.0f) {
            texres->tr/= tot;
            texres->tg/= tot;
            texres->tb/= tot;
            if(texres->talpha) texres->ta/= tot;
        }
    }
    else
        boxsampleclip(ibuf, rf, texres);

    if(texres->talpha==0) texres->ta= 1.0;
    
    if(alphaclip!=1.0f) {
        /* premul it all */
        texres->tr*= alphaclip;
        texres->tg*= alphaclip;
        texres->tb*= alphaclip;
        texres->ta*= alphaclip;
    }
}   

//-----------------------------------------------------------------------------------------------------------------
// from here, some functions only used for the new filtering

// anisotropic filters, data struct used instead of long line of (possibly unused) func args
typedef struct afdata_t {
    float dxt[2], dyt[2];
    int intpol, extflag;
    // feline only
    float majrad, minrad, theta;
    int iProbes;
    float dusc, dvsc;
} afdata_t;

// this only used here to make it easier to pass extend flags as single int
enum {TXC_XMIR=1, TXC_YMIR, TXC_REPT, TXC_EXTD};

// similar to ibuf_get_color() but clips/wraps coords according to repeat/extend flags
// returns true if out of range in clipmode
static int ibuf_get_color_clip(float *col, ImBuf *ibuf, int x, int y, int extflag)
{
    int clip = 0;
    switch (extflag) {
        case TXC_XMIR:  // y rep
            x %= 2*ibuf->x;
            x += x < 0 ? 2*ibuf->x : 0;
            x = x >= ibuf->x ? 2*ibuf->x - x - 1 : x;
            y %= ibuf->y;
            y += y < 0 ? ibuf->y : 0;
            break;
        case TXC_YMIR:  // x rep
            x %= ibuf->x;
            x += x < 0 ? ibuf->x : 0;
            y %= 2*ibuf->y;
            y += y < 0 ? 2*ibuf->y : 0;
            y = y >= ibuf->y ? 2*ibuf->y - y - 1 : y;
            break;
        case TXC_EXTD:
            x = (x < 0) ? 0 : ((x >= ibuf->x) ? (ibuf->x - 1) : x);
            y = (y < 0) ? 0 : ((y >= ibuf->y) ? (ibuf->y - 1) : y);
            break;
        case TXC_REPT:
            x %= ibuf->x;
            x += (x < 0) ? ibuf->x : 0;
            y %= ibuf->y;
            y += (y < 0) ? ibuf->y : 0;
            break;
        default:    {   // as extend, if clipped, set alpha to 0.0
            if (x < 0) { x = 0;  } // TXF alpha: clip = 1; }
            if (x >= ibuf->x) { x = ibuf->x - 1; } // TXF alpha:  clip = 1; }
            if (y < 0) { y = 0; } // TXF alpha:  clip = 1; }
            if (y >= ibuf->y) { y = ibuf->y - 1; } // TXF alpha:  clip = 1; }
        }
    }

    if (ibuf->rect_float) {
        const float* fp = ibuf->rect_float + (x + y*ibuf->x)*ibuf->channels;
        if (ibuf->channels == 1)
            col[0] = col[1] = col[2] = col[3] = *fp;
        else {
            col[0] = fp[0];
            col[1] = fp[1];
            col[2] = fp[2];
            col[3] = clip ? 0.f : (ibuf->channels == 4 ? fp[3] : 1.f);
        }
    }
    else {
        char* rect = (char*)(ibuf->rect + x + y*ibuf->x);
        col[0] = rect[0]*(1.f/255.f);
        col[1] = rect[1]*(1.f/255.f);
        col[2] = rect[2]*(1.f/255.f);
        col[3] = clip ? 0.f : rect[3]*(1.f/255.f);
    }
    return clip;
}

// as above + bilerp
static int ibuf_get_color_clip_bilerp(float *col, ImBuf *ibuf, float u, float v, int intpol, int extflag)
{
    if (intpol) {
        float c00[4], c01[4], c10[4], c11[4];
        const float ufl = floorf(u -= 0.5f), vfl = floorf(v -= 0.5f);
        const float uf = u - ufl, vf = v - vfl;
        const float w00=(1.f-uf)*(1.f-vf), w10=uf*(1.f-vf), w01=(1.f-uf)*vf, w11=uf*vf;
        const int x1 = (int)ufl, y1 = (int)vfl, x2 = x1 + 1, y2 = y1 + 1;
        int clip = ibuf_get_color_clip(c00, ibuf, x1, y1, extflag);
        clip |= ibuf_get_color_clip(c10, ibuf, x2, y1, extflag);
        clip |= ibuf_get_color_clip(c01, ibuf, x1, y2, extflag);
        clip |= ibuf_get_color_clip(c11, ibuf, x2, y2, extflag);
        col[0] = w00*c00[0] + w10*c10[0] + w01*c01[0] + w11*c11[0];
        col[1] = w00*c00[1] + w10*c10[1] + w01*c01[1] + w11*c11[1];
        col[2] = w00*c00[2] + w10*c10[2] + w01*c01[2] + w11*c11[2];
        col[3] = clip ? 0.f : w00*c00[3] + w10*c10[3] + w01*c01[3] + w11*c11[3];
        return clip;
    }
    return ibuf_get_color_clip(col, ibuf, (int)u, (int)v, extflag);
}

static void area_sample(TexResult* texr, ImBuf* ibuf, float fx, float fy, afdata_t* AFD)
{
    int xs, ys, clip = 0;
    float tc[4], xsd, ysd, cw = 0.f;
    const float ux = ibuf->x*AFD->dxt[0], uy = ibuf->y*AFD->dxt[1];
    const float vx = ibuf->x*AFD->dyt[0], vy = ibuf->y*AFD->dyt[1];
    int xsam = (int)(0.5f*sqrtf(ux*ux + uy*uy) + 0.5f);
    int ysam = (int)(0.5f*sqrtf(vx*vx + vy*vy) + 0.5f);
    const int minsam = AFD->intpol ? 2 : 4;
    xsam = CLAMPIS(xsam, minsam, ibuf->x*2);
    ysam = CLAMPIS(ysam, minsam, ibuf->y*2);
    xsd = 1.f / xsam;
    ysd = 1.f / ysam;
    texr->tr = texr->tg = texr->tb = texr->ta = 0.f;
    for (ys=0; ys<ysam; ++ys) {
        for (xs=0; xs<xsam; ++xs) {
            const float su = (xs + ((ys & 1) + 0.5f)*0.5f)*xsd - 0.5f;
            const float sv = (ys + ((xs & 1) + 0.5f)*0.5f)*ysd - 0.5f;
            const float pu = fx + su*AFD->dxt[0] + sv*AFD->dyt[0];
            const float pv = fy + su*AFD->dxt[1] + sv*AFD->dyt[1];
            const int out = ibuf_get_color_clip_bilerp(tc, ibuf, pu*ibuf->x, pv*ibuf->y, AFD->intpol, AFD->extflag);
            clip |= out;
            cw += out ? 0.f : 1.f;
            texr->tr += tc[0];
            texr->tg += tc[1];
            texr->tb += tc[2];
            texr->ta += texr->talpha ? tc[3] : 0.f;
        }
    }
    xsd *= ysd;
    texr->tr *= xsd;
    texr->tg *= xsd;
    texr->tb *= xsd;
    // clipping can be ignored if alpha used, texr->ta already includes filtered edge
    texr->ta = texr->talpha ? texr->ta*xsd : (clip ? cw*xsd : 1.f);
}

// table of (exp(ar) - exp(a)) / (1 - exp(a)) for r in range [0, 1] and a = -2
// used instead of actual gaussian, otherwise at high texture magnifications circular artifacts are visible
#define EWA_MAXIDX 255
static float EWA_WTS[EWA_MAXIDX + 1] =
{ 1.f, 0.990965f, 0.982f, 0.973105f, 0.96428f, 0.955524f, 0.946836f, 0.938216f, 0.929664f,
 0.921178f, 0.912759f, 0.904405f, 0.896117f, 0.887893f, 0.879734f, 0.871638f, 0.863605f,
 0.855636f, 0.847728f, 0.839883f, 0.832098f, 0.824375f, 0.816712f, 0.809108f, 0.801564f,
 0.794079f, 0.786653f, 0.779284f, 0.771974f, 0.76472f, 0.757523f, 0.750382f, 0.743297f,
 0.736267f, 0.729292f, 0.722372f, 0.715505f, 0.708693f, 0.701933f, 0.695227f, 0.688572f,
 0.68197f, 0.67542f, 0.66892f, 0.662471f, 0.656073f, 0.649725f, 0.643426f, 0.637176f,
 0.630976f, 0.624824f, 0.618719f, 0.612663f, 0.606654f, 0.600691f, 0.594776f, 0.588906f,
 0.583083f, 0.577305f, 0.571572f, 0.565883f, 0.56024f, 0.55464f, 0.549084f, 0.543572f,
 0.538102f, 0.532676f, 0.527291f, 0.521949f, 0.516649f, 0.511389f, 0.506171f, 0.500994f,
 0.495857f, 0.490761f, 0.485704f, 0.480687f, 0.475709f, 0.470769f, 0.465869f, 0.461006f,
 0.456182f, 0.451395f, 0.446646f, 0.441934f, 0.437258f, 0.432619f, 0.428017f, 0.42345f,
 0.418919f, 0.414424f, 0.409963f, 0.405538f, 0.401147f, 0.39679f, 0.392467f, 0.388178f,
 0.383923f, 0.379701f, 0.375511f, 0.371355f, 0.367231f, 0.363139f, 0.359079f, 0.355051f,
 0.351055f, 0.347089f, 0.343155f, 0.339251f, 0.335378f, 0.331535f, 0.327722f, 0.323939f,
 0.320186f, 0.316461f, 0.312766f, 0.3091f, 0.305462f, 0.301853f, 0.298272f, 0.294719f,
 0.291194f, 0.287696f, 0.284226f, 0.280782f, 0.277366f, 0.273976f, 0.270613f, 0.267276f,
 0.263965f, 0.26068f, 0.257421f, 0.254187f, 0.250979f, 0.247795f, 0.244636f, 0.241502f,
 0.238393f, 0.235308f, 0.232246f, 0.229209f, 0.226196f, 0.223206f, 0.220239f, 0.217296f,
 0.214375f, 0.211478f, 0.208603f, 0.20575f, 0.20292f, 0.200112f, 0.197326f, 0.194562f,
 0.191819f, 0.189097f, 0.186397f, 0.183718f, 0.18106f, 0.178423f, 0.175806f, 0.17321f,
 0.170634f, 0.168078f, 0.165542f, 0.163026f, 0.16053f, 0.158053f, 0.155595f, 0.153157f,
 0.150738f, 0.148337f, 0.145955f, 0.143592f, 0.141248f, 0.138921f, 0.136613f, 0.134323f,
 0.132051f, 0.129797f, 0.12756f, 0.125341f, 0.123139f, 0.120954f, 0.118786f, 0.116635f,
 0.114501f, 0.112384f, 0.110283f, 0.108199f, 0.106131f, 0.104079f, 0.102043f, 0.100023f,
 0.0980186f, 0.09603f, 0.094057f, 0.0920994f, 0.0901571f, 0.08823f, 0.0863179f, 0.0844208f,
 0.0825384f, 0.0806708f, 0.0788178f, 0.0769792f, 0.0751551f, 0.0733451f, 0.0715493f, 0.0697676f,
 0.0679997f, 0.0662457f, 0.0645054f, 0.0627786f, 0.0610654f, 0.0593655f, 0.0576789f, 0.0560055f,
 0.0543452f, 0.0526979f, 0.0510634f, 0.0494416f, 0.0478326f, 0.0462361f, 0.0446521f, 0.0430805f,
 0.0415211f, 0.039974f, 0.0384389f, 0.0369158f, 0.0354046f, 0.0339052f, 0.0324175f, 0.0309415f,
 0.029477f, 0.0280239f, 0.0265822f, 0.0251517f, 0.0237324f, 0.0223242f, 0.020927f, 0.0195408f,
 0.0181653f, 0.0168006f, 0.0154466f, 0.0141031f, 0.0127701f, 0.0114476f, 0.0101354f, 0.00883339f,
 0.00754159f, 0.00625989f, 0.00498819f, 0.00372644f, 0.00247454f, 0.00123242f, 0.f
};

// test if a float value is 'nan'
// there is a C99 function for this: isnan(), but blender seems to use C90 (according to gcc warns),
// and may not be supported by other compilers either
#ifndef ISNAN
#define ISNAN(x) ((x) != (x))
#endif
//static int ISNAN(float x) { return (x != x); }

static void radangle2imp(float a2, float b2, float th, float* A, float* B, float* C, float* F)
{
    float ct2 = cosf(th);
    const float st2 = 1.f - ct2*ct2;    // <- sin(th)^2
    ct2 *= ct2;
    *A = a2*st2 + b2*ct2;
    *B = (b2 - a2)*sinf(2.f*th);
    *C = a2*ct2 + b2*st2;
    *F = a2*b2;
}

// all tests here are done to make sure possible overflows are hopefully minimized
static void imp2radangle(float A, float B, float C, float F, float* a, float* b, float* th, float* ecc)
{
    if (F <= 1e-5f) {   // use arbitrary major radius, zero minor, infinite eccentricity
        *a = sqrtf(A > C ? A : C);
        *b = 0.f;
        *ecc = 1e10f;
        *th = 0.5f*(atan2f(B, A - C) + (float)M_PI);
    }
    else {
        const float AmC = A - C, ApC = A + C, F2 = F*2.f;
        const float r = sqrtf(AmC*AmC + B*B);
        float d = ApC - r;
        *a = (d <= 0.f) ? sqrtf(A > C ? A : C) : sqrtf(F2 / d);
        d = ApC + r;
        if (d <= 0.f) {
            *b = 0.f;
            *ecc = 1e10f;
        }
        else {
            *b = sqrtf(F2 / d);
            *ecc = *a / *b;
        }
        // incr theta by 0.5*pi (angle of major axis)
        *th = 0.5f*(atan2f(B, AmC) + (float)M_PI);
    }
}

static void ewa_eval(TexResult* texr, ImBuf* ibuf, float fx, float fy, afdata_t* AFD)
{
    // scaling dxt/dyt by full resolution can cause overflow because of huge A/B/C and esp. F values,
    // scaling by aspect ratio alone does the opposite, so try something in between instead...
    const float ff2 = ibuf->x, ff = sqrtf(ff2), q = ibuf->y / ff;
    const float Ux = AFD->dxt[0]*ff, Vx = AFD->dxt[1]*q, Uy = AFD->dyt[0]*ff, Vy = AFD->dyt[1]*q;
    float A = Vx*Vx + Vy*Vy;
    float B = -2.f*(Ux*Vx + Uy*Vy);
    float C = Ux*Ux + Uy*Uy;
    float F = A*C - B*B*0.25f;
    float a, b, th, ecc, a2, b2, ue, ve, U0, V0, DDQ, U, ac1, ac2, BU, d; // TXF alpha: cw = 0.f;
    int u, v, u1, u2, v1, v2; // TXF alpha: clip = 0;

    // The so-called 'high' quality ewa method simply adds a constant of 1 to both A & C,
    // so the ellipse always covers at least some texels. But since the filter is now always larger,
    // it also means that everywhere else it's also more blurry then ideally should be the case.
    // So instead here the ellipse radii are modified instead whenever either is too low.
    // Use a different radius based on interpolation switch, just enough to anti-alias when interpolation is off,
    // and slightly larger to make result a bit smoother than bilinear interpolation when interpolation is on
    // (minimum values: const float rmin = intpol ? 1.f : 0.5f;)
    const float rmin = (AFD->intpol ? 1.5625f : 0.765625f)/ff2;
    imp2radangle(A, B, C, F, &a, &b, &th, &ecc);
    if ((b2 = b*b) < rmin) {
        if ((a2 = a*a) < rmin) {
            B = 0.f;
            A = C = rmin;
            F = A*C;
        }
        else {
            b2 = rmin;
            radangle2imp(a2, b2, th, &A, &B, &C, &F);
        }
    }

    ue = ff*sqrtf(C);
    ve = ff*sqrtf(A);
    d = (float)(EWA_MAXIDX + 1) / (F*ff2);
    A *= d;
    B *= d;
    C *= d;

    U0 = fx*ibuf->x;
    V0 = fy*ibuf->y;
    u1 = (int)(floorf(U0 - ue));
    u2 = (int)(ceilf(U0 + ue));
    v1 = (int)(floorf(V0 - ve));
    v2 = (int)(ceilf(V0 + ve));
    U0 -= 0.5f;
    V0 -= 0.5f;
    DDQ = 2.f*A;
    U = u1 - U0;
    ac1 = A*(2.f*U + 1.f);
    ac2 = A*U*U;
    BU = B*U;

    d = texr->tr = texr->tb = texr->tg = texr->ta = 0.f;
    for (v=v1; v<=v2; ++v) {
        const float V = v - V0;
        float DQ = ac1 + B*V;
        float Q = (C*V + BU)*V + ac2;
        for (u=u1; u<=u2; ++u) {
            if (Q < (float)(EWA_MAXIDX + 1)) {
                float tc[4];
                const float wt = EWA_WTS[(Q < 0.f) ? 0 : (unsigned int)Q];
                /*const int out =*/ ibuf_get_color_clip(tc, ibuf, u, v, AFD->extflag);
                // TXF alpha: clip |= out;
                // TXF alpha: cw += out ? 0.f : wt;
                texr->tr += tc[0]*wt;
                texr->tg += tc[1]*wt;
                texr->tb += tc[2]*wt;
                texr->ta += texr->talpha ? tc[3]*wt : 0.f;
                d += wt;
            }
            Q += DQ;
            DQ += DDQ;
        }
    }

    // d should hopefully never be zero anymore
    d = 1.f/d;
    texr->tr *= d;
    texr->tg *= d;
    texr->tb *= d;
    // clipping can be ignored if alpha used, texr->ta already includes filtered edge
    texr->ta = texr->talpha ? texr->ta*d : 1.f; // TXF alpha (clip ? cw*d : 1.f);
}

static void feline_eval(TexResult* texr, ImBuf* ibuf, float fx, float fy, afdata_t* AFD)
{
    const int maxn = AFD->iProbes - 1;
    const float ll = ((AFD->majrad == AFD->minrad) ? 2.f*AFD->majrad : 2.f*(AFD->majrad - AFD->minrad)) / (maxn ? (float)maxn : 1.f);
    float du = maxn ? cosf(AFD->theta)*ll : 0.f;
    float dv = maxn ? sinf(AFD->theta)*ll : 0.f;
    //const float D = -0.5f*(du*du + dv*dv) / (AFD->majrad*AFD->majrad);
    const float D = (EWA_MAXIDX + 1)*0.25f*(du*du + dv*dv) / (AFD->majrad*AFD->majrad);
    float d; // TXF alpha: cw = 0.f;
    int n; // TXF alpha: clip = 0;
    // have to use same scaling for du/dv here as for Ux/Vx/Uy/Vy (*after* D calc.)
    du *= AFD->dusc;
    dv *= AFD->dvsc;
    d = texr->tr = texr->tb = texr->tg = texr->ta = 0.f;
    for (n=-maxn; n<=maxn; n+=2) {
        float tc[4];
        const float hn = n*0.5f;
        const float u = fx + hn*du, v = fy + hn*dv;
        //const float wt = expf(n*n*D);
        // can use ewa table here too
        const float wt = EWA_WTS[(int)(n*n*D)];
        /*const int out =*/ ibuf_get_color_clip_bilerp(tc, ibuf, ibuf->x*u, ibuf->y*v, AFD->intpol, AFD->extflag);
        // TXF alpha: clip |= out;
        // TXF alpha: cw += out ? 0.f : wt;
        texr->tr += tc[0]*wt;
        texr->tg += tc[1]*wt;
        texr->tb += tc[2]*wt;
        texr->ta += texr->talpha ? tc[3]*wt : 0.f;
        d += wt;
    }

    d = 1.f/d;
    texr->tr *= d;
    texr->tg *= d;
    texr->tb *= d;
    // clipping can be ignored if alpha used, texr->ta already includes filtered edge
    texr->ta = texr->talpha ? texr->ta*d : 1.f; // TXF alpha: (clip ? cw*d : 1.f);
}
#undef EWA_MAXIDX

static void alpha_clip_aniso(ImBuf *ibuf, float minx, float miny, float maxx, float maxy, int extflag, TexResult *texres)
{
    float alphaclip;
    rctf rf;

    // TXF apha: we're doing the same alphaclip here as boxsample, but i'm doubting
    // if this is actually correct for the all the filtering algorithms ..

    if(!(extflag == TXC_REPT || extflag == TXC_EXTD)) {
        rf.xmin= minx*(ibuf->x);
        rf.xmax= maxx*(ibuf->x);
        rf.ymin= miny*(ibuf->y);
        rf.ymax= maxy*(ibuf->y);

        alphaclip = clipx_rctf(&rf, 0.0, (float)(ibuf->x));
        alphaclip*= clipy_rctf(&rf, 0.0, (float)(ibuf->y));
        alphaclip= MAX2(alphaclip, 0.0f);

        if(alphaclip!=1.0f) {
            /* premul it all */
            texres->tr*= alphaclip;
            texres->tg*= alphaclip;
            texres->tb*= alphaclip;
            texres->ta*= alphaclip;
        }
    }
}

static void image_mipmap_test(Tex *tex, ImBuf *ibuf)
{
    if (tex->imaflag & TEX_MIPMAP) {
        if ((ibuf->flags & IB_fields) == 0) {
            
            if (ibuf->mipmap[0] && (ibuf->userflags & IB_MIPMAP_INVALID)) {
                BLI_lock_thread(LOCK_IMAGE);
                if (ibuf->userflags & IB_MIPMAP_INVALID) {
                    IMB_remakemipmap(ibuf, tex->imaflag & TEX_GAUSS_MIP);
                    ibuf->userflags &= ~IB_MIPMAP_INVALID;
                }               
                BLI_unlock_thread(LOCK_IMAGE);
            }
            if (ibuf->mipmap[0] == NULL) {
                BLI_lock_thread(LOCK_IMAGE);
                if (ibuf->mipmap[0] == NULL) 
                    IMB_makemipmap(ibuf, tex->imaflag & TEX_GAUSS_MIP);
                BLI_unlock_thread(LOCK_IMAGE);
            }
        }
    }
    
}

static int imagewraposa_aniso(Tex *tex, Image *ima, ImBuf *ibuf, const float texvec[3], float dxt[3], float dyt[3], TexResult *texres)
{
    TexResult texr;
    float fx, fy, minx, maxx, miny, maxy;
    float maxd, val1, val2, val3;
    int curmap, retval, intpol, extflag = 0;
    afdata_t AFD;

    void (*filterfunc)(TexResult*, ImBuf*, float, float, afdata_t*);
    switch (tex->texfilter) {
        case TXF_EWA:
            filterfunc = ewa_eval;
            break;
        case TXF_FELINE:
            filterfunc = feline_eval;
            break;
        case TXF_AREA:
        default:
            filterfunc = area_sample;
    }

    texres->tin = texres->ta = texres->tr = texres->tg = texres->tb = 0.f;

    // we need to set retval OK, otherwise texture code generates normals itself...
    retval = texres->nor ? 3 : 1;

    // quick tests
    if (ibuf==NULL && ima==NULL) return retval;

    if (ima) {  // hack for icon render
        if ((ima->ibufs.first == NULL) && (R.r.scemode & R_NO_IMAGE_LOAD)) return retval;
        ibuf = BKE_image_get_ibuf(ima, &tex->iuser); 
    }

    if ((ibuf == NULL) || ((ibuf->rect == NULL) && (ibuf->rect_float == NULL))) return retval;

    /* mipmap test */
    image_mipmap_test(tex, ibuf);
    
    if ((tex->imaflag & TEX_USEALPHA) && ((tex->imaflag & TEX_CALCALPHA) == 0)) texres->talpha = 1;
    texr.talpha = texres->talpha;

    if (tex->imaflag & TEX_IMAROT) {
        fy = texvec[0];
        fx = texvec[1];
    }
    else {
        fx = texvec[0];
        fy = texvec[1];
    }

    if (ibuf->flags & IB_fields) {
        if (R.r.mode & R_FIELDS) {          /* field render */
            if (R.flag & R_SEC_FIELD) {     /* correction for 2nd field */
                /* fac1= 0.5/( (float)ibuf->y ); */
                /* fy-= fac1; */
            }
            else    /* first field */
                fy += 0.5f/( (float)ibuf->y );
        }
    }

    // pixel coordinates
    minx = MIN3(dxt[0], dyt[0], dxt[0] + dyt[0]);
    maxx = MAX3(dxt[0], dyt[0], dxt[0] + dyt[0]);
    miny = MIN3(dxt[1], dyt[1], dxt[1] + dyt[1]);
    maxy = MAX3(dxt[1], dyt[1], dxt[1] + dyt[1]);

    // tex_sharper has been removed
    minx = (maxx - minx)*0.5f;
    miny = (maxy - miny)*0.5f;

    if (tex->imaflag & TEX_FILTER_MIN) {
        // make sure the filtersize is minimal in pixels (normal, ref map can have miniature pixel dx/dy)
        const float addval = (0.5f * tex->filtersize) / (float)MIN2(ibuf->x, ibuf->y);
        if (addval > minx) minx = addval;
        if (addval > miny) miny = addval;
    }
    else if (tex->filtersize != 1.f) {
        minx *= tex->filtersize;
        miny *= tex->filtersize;
        dxt[0] *= tex->filtersize;
        dxt[1] *= tex->filtersize;
        dyt[0] *= tex->filtersize;
        dyt[1] *= tex->filtersize;
    }

    if (tex->imaflag & TEX_IMAROT) {
        float t;
        SWAP(float, minx, miny);
        // must rotate dxt/dyt 90 deg
        // yet another blender problem is that swapping X/Y axes (or any tex proj switches) should do something similar,
        // but it doesn't, it only swaps coords, so filter area will be incorrect in those cases.
        t = dxt[0];
        dxt[0] = dxt[1];
        dxt[1] = -t;
        t = dyt[0];
        dyt[0] = dyt[1];
        dyt[1] = -t;
    }

    // side faces of unit-cube
    minx = (minx > 0.25f) ? 0.25f : ((minx < 1e-5f) ? 1e-5f : minx);
    miny = (miny > 0.25f) ? 0.25f : ((miny < 1e-5f) ? 1e-5f : miny);

    // repeat and clip

    if (tex->extend == TEX_REPEAT) {
        if ((tex->flag & (TEX_REPEAT_XMIR | TEX_REPEAT_YMIR)) == (TEX_REPEAT_XMIR | TEX_REPEAT_YMIR))
            extflag = TXC_EXTD;
        else if (tex->flag & TEX_REPEAT_XMIR)
            extflag = TXC_XMIR;
        else if (tex->flag & TEX_REPEAT_YMIR)
            extflag = TXC_YMIR;
        else
            extflag = TXC_REPT;
    }
    else if (tex->extend == TEX_EXTEND)
        extflag = TXC_EXTD;

    if (tex->extend == TEX_CHECKER) {
        int xs = (int)floorf(fx), ys = (int)floorf(fy);
        // both checkers available, no boundary exceptions, checkerdist will eat aliasing
        if ((tex->flag & TEX_CHECKER_ODD) && (tex->flag & TEX_CHECKER_EVEN)) {
            fx -= xs;
            fy -= ys;
        }
        else {
            int xs1 = (int)floorf(fx - minx);
            int ys1 = (int)floorf(fy - miny);
            int xs2 = (int)floorf(fx + minx);
            int ys2 = (int)floorf(fy + miny);
            if ((xs1 != xs2) || (ys1 != ys2)) {
                if (tex->flag & TEX_CHECKER_ODD) {
                    fx -= ((xs1 + ys) & 1) ? xs2 : xs1;
                    fy -= ((ys1 + xs) & 1) ? ys2 : ys1;
                }
                if (tex->flag & TEX_CHECKER_EVEN) {
                    fx -= ((xs1 + ys) & 1) ? xs1 : xs2;
                    fy -= ((ys1 + xs) & 1) ? ys1 : ys2;
                }
            }
            else {
                if ((tex->flag & TEX_CHECKER_ODD) == 0 && ((xs + ys) & 1) == 0) return retval;
                if ((tex->flag & TEX_CHECKER_EVEN) == 0 && (xs + ys) & 1) return retval;
                fx -= xs;
                fy -= ys;
            }
        }
        // scale around center, (0.5, 0.5)
        if (tex->checkerdist < 1.f) {
            const float omcd = 1.f / (1.f - tex->checkerdist);
            fx = (fx - 0.5f)*omcd + 0.5f;
            fy = (fy - 0.5f)*omcd + 0.5f;
            minx *= omcd;
            miny *= omcd;
        }
    }

    if (tex->extend == TEX_CLIPCUBE) {
        if ((fx + minx) < 0.f || (fy + miny) < 0.f || (fx - minx) > 1.f || (fy - miny) > 1.f || texvec[2] < -1.f || texvec[2] > 1.f) return retval;
    }
    else if (tex->extend == TEX_CLIP || tex->extend == TEX_CHECKER) {
        if ((fx + minx) < 0.f || (fy + miny) < 0.f || (fx - minx) > 1.f || (fy - miny) > 1.f) return retval;
    }
    else {
        if (tex->extend == TEX_EXTEND) {
            fx = (fx > 1.f) ? 1.f : ((fx < 0.f) ? 0.f : fx);
            fy = (fy > 1.f) ? 1.f : ((fy < 0.f) ? 0.f : fy);
        }
        else {
            fx -= floorf(fx);
            fy -= floorf(fy);
        }
    }

    intpol = tex->imaflag & TEX_INTERPOL;

    // warning no return!
    if ((R.flag & R_SEC_FIELD) && (ibuf->flags & IB_fields))
        ibuf->rect += ibuf->x*ibuf->y;

    // struct common data
    copy_v2_v2(AFD.dxt, dxt);
    copy_v2_v2(AFD.dyt, dyt);
    AFD.intpol = intpol;
    AFD.extflag = extflag;

    // brecht: added stupid clamping here, large dx/dy can give very large
    // filter sizes which take ages to render, it may be better to do this
    // more intelligently later in the code .. probably it's not noticeable
    if(AFD.dxt[0]*AFD.dxt[0] + AFD.dxt[1]*AFD.dxt[1] > 2.0f*2.0f)
        mul_v2_fl(AFD.dxt, 2.0f/len_v2(AFD.dxt));
    if(AFD.dyt[0]*AFD.dyt[0] + AFD.dyt[1]*AFD.dyt[1] > 2.0f*2.0f)
        mul_v2_fl(AFD.dyt, 2.0f/len_v2(AFD.dyt));

    // choice:
    if (tex->imaflag & TEX_MIPMAP) {
        ImBuf *previbuf, *curibuf;
        float levf;
        int maxlev;
        ImBuf* mipmaps[IB_MIPMAP_LEVELS + 1];

        // modify ellipse minor axis if too eccentric, use for area sampling as well
        // scaling dxt/dyt as done in pbrt is not the same
        // (as in ewa_eval(), scale by sqrt(ibuf->x) to maximize precision)
        const float ff = sqrtf(ibuf->x), q = ibuf->y/ff;
        const float Ux = dxt[0]*ff, Vx = dxt[1]*q, Uy = dyt[0]*ff, Vy = dyt[1]*q;
        const float A = Vx*Vx + Vy*Vy;
        const float B = -2.f*(Ux*Vx + Uy*Vy);
        const float C = Ux*Ux + Uy*Uy;
        const float F = A*C - B*B*0.25f;
        float a, b, th, ecc;
        imp2radangle(A, B, C, F, &a, &b, &th, &ecc);
        if (tex->texfilter == TXF_FELINE) {
            float fProbes;
            a *= ff;
            b *= ff;
            a = MAX2(a, 1.f);
            b = MAX2(b, 1.f);
            fProbes = 2.f*(a / b) - 1.f;
            AFD.iProbes = (int)floorf(fProbes + 0.5f);
            AFD.iProbes = MIN2(AFD.iProbes, tex->afmax);
            if (AFD.iProbes < fProbes)
                b = 2.f*a / (float)(AFD.iProbes + 1);
            AFD.majrad = a/ff;
            AFD.minrad = b/ff;
            AFD.theta = th;
            AFD.dusc = 1.f/ff;
            AFD.dvsc = ff / (float)ibuf->y;
        }
        else {  // EWA & area
            if (ecc > (float)tex->afmax) b = a / (float)tex->afmax;
            b *= ff;
        }
        maxd = MAX2(b, 1e-8f);
        levf = ((float)M_LOG2E)*logf(maxd);

        curmap = 0;
        maxlev = 1;
        mipmaps[0] = ibuf;
        while (curmap < IB_MIPMAP_LEVELS) {
            mipmaps[curmap + 1] = ibuf->mipmap[curmap];
            if (ibuf->mipmap[curmap]) maxlev++;
            curmap++;
        }

        // mipmap level
        if (levf < 0.f) {   // original image only
            previbuf = curibuf = mipmaps[0];
            levf = 0.f;
        }
        else if (levf >= maxlev - 1) {
            previbuf = curibuf = mipmaps[maxlev - 1];
            levf = 0.f;
            if (tex->texfilter == TXF_FELINE) AFD.iProbes = 1;
        }
        else {
            const int lev = ISNAN(levf) ? 0 : (int)levf;
            curibuf = mipmaps[lev];
            previbuf = mipmaps[lev + 1];
            levf -= floorf(levf);
        }

        // filter functions take care of interpolation themselves, no need to modify dxt/dyt here

        if (texres->nor && ((tex->imaflag & TEX_NORMALMAP) == 0)) {
            // color & normal
            filterfunc(texres, curibuf, fx, fy, &AFD);
            val1 = texres->tr + texres->tg + texres->tb;
            filterfunc(&texr, curibuf, fx + dxt[0], fy + dxt[1], &AFD);
            val2 = texr.tr + texr.tg + texr.tb;
            filterfunc(&texr, curibuf, fx + dyt[0], fy + dyt[1], &AFD);
            val3 = texr.tr + texr.tg + texr.tb;
            // don't switch x or y!
            texres->nor[0] = val1 - val2;
            texres->nor[1] = val1 - val3;
            if (previbuf != curibuf) {  // interpolate
                filterfunc(&texr, previbuf, fx, fy, &AFD);
                // rgb
                texres->tr += levf*(texr.tr - texres->tr);
                texres->tg += levf*(texr.tg - texres->tg);
                texres->tb += levf*(texr.tb - texres->tb);
                texres->ta += levf*(texr.ta - texres->ta);
                // normal
                val1 += levf*((texr.tr + texr.tg + texr.tb) - val1);
                filterfunc(&texr, previbuf, fx + dxt[0], fy + dxt[1], &AFD);
                val2 += levf*((texr.tr + texr.tg + texr.tb) - val2);
                filterfunc(&texr, previbuf, fx + dyt[0], fy + dyt[1], &AFD);
                val3 += levf*((texr.tr + texr.tg + texr.tb) - val3);
                texres->nor[0] = val1 - val2;   // vals have been interpolated above!
                texres->nor[1] = val1 - val3;
            }
        }
        else {  // color
            filterfunc(texres, curibuf, fx, fy, &AFD);
            if (previbuf != curibuf) {  // interpolate
                filterfunc(&texr, previbuf, fx, fy, &AFD);
                texres->tr += levf*(texr.tr - texres->tr);
                texres->tg += levf*(texr.tg - texres->tg);
                texres->tb += levf*(texr.tb - texres->tb);
                texres->ta += levf*(texr.ta - texres->ta);
            }

            alpha_clip_aniso(ibuf, fx-minx, fy-miny, fx+minx, fy+miny, extflag, texres);
        }
    }
    else {  // no mipmap
        // filter functions take care of interpolation themselves, no need to modify dxt/dyt here
        if (tex->texfilter == TXF_FELINE) {
            const float ff = sqrtf(ibuf->x), q = ibuf->y/ff;
            const float Ux = dxt[0]*ff, Vx = dxt[1]*q, Uy = dyt[0]*ff, Vy = dyt[1]*q;
            const float A = Vx*Vx + Vy*Vy;
            const float B = -2.f*(Ux*Vx + Uy*Vy);
            const float C = Ux*Ux + Uy*Uy;
            const float F = A*C - B*B*0.25f;
            float a, b, th, ecc, fProbes;
            imp2radangle(A, B, C, F, &a, &b, &th, &ecc);
            a *= ff;
            b *= ff;
            a = MAX2(a, 1.f);
            b = MAX2(b, 1.f);
            fProbes = 2.f*(a / b) - 1.f;
            // no limit to number of Probes here
            AFD.iProbes = (int)floorf(fProbes + 0.5f);
            if (AFD.iProbes < fProbes) b = 2.f*a / (float)(AFD.iProbes + 1);
            AFD.majrad = a/ff;
            AFD.minrad = b/ff;
            AFD.theta = th;
            AFD.dusc = 1.f/ff;
            AFD.dvsc = ff / (float)ibuf->y;
        }
        if (texres->nor && ((tex->imaflag & TEX_NORMALMAP) == 0)) {
            // color & normal
            filterfunc(texres, ibuf, fx, fy, &AFD);
            val1 = texres->tr + texres->tg + texres->tb;
            filterfunc(&texr, ibuf, fx + dxt[0], fy + dxt[1], &AFD);
            val2 = texr.tr + texr.tg + texr.tb;
            filterfunc(&texr, ibuf, fx + dyt[0], fy + dyt[1], &AFD);
            val3 = texr.tr + texr.tg + texr.tb;
            // don't switch x or y!
            texres->nor[0] = val1 - val2;
            texres->nor[1] = val1 - val3;
        }
        else {
            filterfunc(texres, ibuf, fx, fy, &AFD);
            alpha_clip_aniso(ibuf, fx-minx, fy-miny, fx+minx, fy+miny, extflag, texres);
        }
    }

    if (tex->imaflag & TEX_CALCALPHA)
        texres->ta = texres->tin = texres->ta * MAX3(texres->tr, texres->tg, texres->tb);
    else
        texres->tin = texres->ta;
    if (tex->flag & TEX_NEGALPHA) texres->ta = 1.f - texres->ta;
    
    if ((R.flag & R_SEC_FIELD) && (ibuf->flags & IB_fields))
        ibuf->rect -= ibuf->x*ibuf->y;

    if (texres->nor && (tex->imaflag & TEX_NORMALMAP)) {    // normal from color
        // The invert of the red channel is to make
        // the normal map compliant with the outside world.
        // It needs to be done because in Blender
        // the normal used in the renderer points inward. It is generated
        // this way in calc_vertexnormals(). Should this ever change
        // this negate must be removed.
        texres->nor[0] = -2.f*(texres->tr - 0.5f);
        texres->nor[1] = 2.f*(texres->tg - 0.5f);
        texres->nor[2] = 2.f*(texres->tb - 0.5f);
    }
    
    // de-premul, this is being premulled in shade_input_do_shade()
    // TXF: this currently does not (yet?) work properly, destroys edge AA in clip/checker mode, so for now commented out
    // also disabled in imagewraposa() to be able to compare results with blender's default texture filtering

    // brecht: tried to fix this, see "TXF alpha" comments

    if (texres->ta != 1.f && (texres->ta > 1e-4f)) {
        fx = 1.f/texres->ta;
        texres->tr *= fx;
        texres->tg *= fx;
        texres->tb *= fx;
    }

    BRICONTRGB;
    
    return retval;
}


int imagewraposa(Tex *tex, Image *ima, ImBuf *ibuf, const float texvec[3], const float DXT[3], const float DYT[3], TexResult *texres)
{
    TexResult texr;
    float fx, fy, minx, maxx, miny, maxy, dx, dy, dxt[3], dyt[3];
    float maxd, pixsize, val1, val2, val3;
    int curmap, retval, imaprepeat, imapextend;

    // TXF: since dxt/dyt might be modified here and since they might be needed after imagewraposa() call,
    // make a local copy here so that original vecs remain untouched
    copy_v3_v3(dxt, DXT);
    copy_v3_v3(dyt, DYT);

    // anisotropic filtering
    if (tex->texfilter != TXF_BOX)
        return imagewraposa_aniso(tex, ima, ibuf, texvec, dxt, dyt, texres);

    texres->tin= texres->ta= texres->tr= texres->tg= texres->tb= 0.0f;
    
    /* we need to set retval OK, otherwise texture code generates normals itself... */
    retval= texres->nor?3:1;
    
    /* quick tests */
    if(ibuf==NULL && ima==NULL)
        return retval;
    if(ima) {

        /* hack for icon render */
        if(ima->ibufs.first==NULL && (R.r.scemode & R_NO_IMAGE_LOAD))
            return retval;
        
        ibuf= BKE_image_get_ibuf(ima, &tex->iuser); 
    }
    if(ibuf==NULL || (ibuf->rect==NULL && ibuf->rect_float==NULL))
        return retval;
    
    /* mipmap test */
    image_mipmap_test(tex, ibuf);

    if(tex->imaflag & TEX_USEALPHA) {
        if(tex->imaflag & TEX_CALCALPHA);
        else texres->talpha= 1;
    }
    
    texr.talpha= texres->talpha;
    
    if(tex->imaflag & TEX_IMAROT) {
        fy= texvec[0];
        fx= texvec[1];
    }
    else {
        fx= texvec[0];
        fy= texvec[1];
    }
    
    if(ibuf->flags & IB_fields) {
        if(R.r.mode & R_FIELDS) {           /* field render */
            if(R.flag & R_SEC_FIELD) {      /* correction for 2nd field */
                /* fac1= 0.5/( (float)ibuf->y ); */
                /* fy-= fac1; */
            }
            else {              /* first field */
                fy+= 0.5f/( (float)ibuf->y );
            }
        }
    }
    
    /* pixel coordinates */

    minx= MIN3(dxt[0],dyt[0],dxt[0]+dyt[0] );
    maxx= MAX3(dxt[0],dyt[0],dxt[0]+dyt[0] );
    miny= MIN3(dxt[1],dyt[1],dxt[1]+dyt[1] );
    maxy= MAX3(dxt[1],dyt[1],dxt[1]+dyt[1] );

    /* tex_sharper has been removed */
    minx= (maxx-minx)/2.0f;
    miny= (maxy-miny)/2.0f;
    
    if(tex->imaflag & TEX_FILTER_MIN) {
        /* make sure the filtersize is minimal in pixels (normal, ref map can have miniature pixel dx/dy) */
        float addval= (0.5f * tex->filtersize) / (float) MIN2(ibuf->x, ibuf->y);

        if(addval > minx)
            minx= addval;
        if(addval > miny)
            miny= addval;
    }
    else if(tex->filtersize!=1.0f) {
        minx*= tex->filtersize;
        miny*= tex->filtersize;
        
        dxt[0]*= tex->filtersize;
        dxt[1]*= tex->filtersize;
        dyt[0]*= tex->filtersize;
        dyt[1]*= tex->filtersize;
    }

    if(tex->imaflag & TEX_IMAROT) SWAP(float, minx, miny);
    
    if(minx>0.25f) minx= 0.25f;
    else if(minx<0.00001f) minx= 0.00001f;  /* side faces of unit-cube */
    if(miny>0.25f) miny= 0.25f;
    else if(miny<0.00001f) miny= 0.00001f;

    
    /* repeat and clip */
    imaprepeat= (tex->extend==TEX_REPEAT);
    imapextend= (tex->extend==TEX_EXTEND);

    if(tex->extend == TEX_REPEAT) {
        if(tex->flag & (TEX_REPEAT_XMIR|TEX_REPEAT_YMIR)) {
            imaprepeat= 0;
            imapextend= 1;
        }
    }

    if(tex->extend == TEX_CHECKER) {
        int xs, ys, xs1, ys1, xs2, ys2, boundary;
        
        xs= (int)floor(fx);
        ys= (int)floor(fy);
        
        // both checkers available, no boundary exceptions, checkerdist will eat aliasing
        if( (tex->flag & TEX_CHECKER_ODD) && (tex->flag & TEX_CHECKER_EVEN) ) {
            fx-= xs;
            fy-= ys;
        }
        else {
            
            xs1= (int)floor(fx-minx);
            ys1= (int)floor(fy-miny);
            xs2= (int)floor(fx+minx);
            ys2= (int)floor(fy+miny);
            boundary= (xs1!=xs2) || (ys1!=ys2);

            if(boundary==0) {
                if( (tex->flag & TEX_CHECKER_ODD)==0) {
                    if((xs+ys) & 1); 
                    else return retval;
                }
                if( (tex->flag & TEX_CHECKER_EVEN)==0) {
                    if((xs+ys) & 1) return retval;
                }
                fx-= xs;
                fy-= ys;
            }
            else {
                if(tex->flag & TEX_CHECKER_ODD) {
                    if((xs1+ys) & 1) fx-= xs2;
                    else fx-= xs1;
                    
                    if((ys1+xs) & 1) fy-= ys2;
                    else fy-= ys1;
                }
                if(tex->flag & TEX_CHECKER_EVEN) {
                    if((xs1+ys) & 1) fx-= xs1;
                    else fx-= xs2;
                    
                    if((ys1+xs) & 1) fy-= ys1;
                    else fy-= ys2;
                }
            }
        }

        /* scale around center, (0.5, 0.5) */
        if(tex->checkerdist<1.0f) {
            fx= (fx-0.5f)/(1.0f-tex->checkerdist) +0.5f;
            fy= (fy-0.5f)/(1.0f-tex->checkerdist) +0.5f;
            minx/= (1.0f-tex->checkerdist);
            miny/= (1.0f-tex->checkerdist);
        }
    }

    if(tex->extend == TEX_CLIPCUBE) {
        if(fx+minx<0.0f || fy+miny<0.0f || fx-minx>1.0f || fy-miny>1.0f || texvec[2]<-1.0f || texvec[2]>1.0f) {
            return retval;
        }
    }
    else if(tex->extend==TEX_CLIP || tex->extend==TEX_CHECKER) {
        if(fx+minx<0.0f || fy+miny<0.0f || fx-minx>1.0f || fy-miny>1.0f) {
            return retval;
        }
    }
    else {
        if(imapextend) {
            if(fx>1.0f) fx = 1.0f;
            else if(fx<0.0f) fx= 0.0f;
        }
        else {
            if(fx>1.0f) fx -= (int)(fx);
            else if(fx<0.0f) fx+= 1-(int)(fx);
        }
        
        if(imapextend) {
            if(fy>1.0f) fy = 1.0f;
            else if(fy<0.0f) fy= 0.0f;
        }
        else {
            if(fy>1.0f) fy -= (int)(fy);
            else if(fy<0.0f) fy+= 1-(int)(fy);
        }
    }

    /* warning no return! */
    if( (R.flag & R_SEC_FIELD) && (ibuf->flags & IB_fields) ) {
        ibuf->rect+= (ibuf->x*ibuf->y);
    }

    /* choice:  */
    if(tex->imaflag & TEX_MIPMAP) {
        ImBuf *previbuf, *curibuf;
        float bumpscale;
        
        dx= minx;
        dy= miny;
        maxd= MAX2(dx, dy);
        if(maxd>0.5f) maxd= 0.5f;

        pixsize = 1.0f/ (float) MIN2(ibuf->x, ibuf->y);
        
        bumpscale= pixsize/maxd;
        if(bumpscale>1.0f) bumpscale= 1.0f;
        else bumpscale*=bumpscale;
        
        curmap= 0;
        previbuf= curibuf= ibuf;
        while(curmap<IB_MIPMAP_LEVELS && ibuf->mipmap[curmap]) {
            if(maxd < pixsize) break;
            previbuf= curibuf;
            curibuf= ibuf->mipmap[curmap];
            pixsize= 1.0f / (float)MIN2(curibuf->x, curibuf->y);
            curmap++;
        }

        if(previbuf!=curibuf || (tex->imaflag & TEX_INTERPOL)) {
            /* sample at least 1 pixel */
            if (minx < 0.5f / ibuf->x) minx = 0.5f / ibuf->x;
            if (miny < 0.5f / ibuf->y) miny = 0.5f / ibuf->y;
        }
        
        if(texres->nor && (tex->imaflag & TEX_NORMALMAP)==0) {
            /* a bit extra filter */
            //minx*= 1.35f;
            //miny*= 1.35f;
            
            boxsample(curibuf, fx-minx, fy-miny, fx+minx, fy+miny, texres, imaprepeat, imapextend);
            val1= texres->tr+texres->tg+texres->tb;
            boxsample(curibuf, fx-minx+dxt[0], fy-miny+dxt[1], fx+minx+dxt[0], fy+miny+dxt[1], &texr, imaprepeat, imapextend);
            val2= texr.tr + texr.tg + texr.tb;
            boxsample(curibuf, fx-minx+dyt[0], fy-miny+dyt[1], fx+minx+dyt[0], fy+miny+dyt[1], &texr, imaprepeat, imapextend);
            val3= texr.tr + texr.tg + texr.tb;

            /* don't switch x or y! */
            texres->nor[0]= (val1-val2);
            texres->nor[1]= (val1-val3);
            
            if(previbuf!=curibuf) {  /* interpolate */
                
                boxsample(previbuf, fx-minx, fy-miny, fx+minx, fy+miny, &texr, imaprepeat, imapextend);
                
                /* calc rgb */
                dx= 2.0f*(pixsize-maxd)/pixsize;
                if(dx>=1.0f) {
                    texres->ta= texr.ta; texres->tb= texr.tb;
                    texres->tg= texr.tg; texres->tr= texr.tr;
                }
                else {
                    dy= 1.0f-dx;
                    texres->tb= dy*texres->tb+ dx*texr.tb;
                    texres->tg= dy*texres->tg+ dx*texr.tg;
                    texres->tr= dy*texres->tr+ dx*texr.tr;
                    texres->ta= dy*texres->ta+ dx*texr.ta;
                }
                
                val1= dy*val1+ dx*(texr.tr + texr.tg + texr.tb);
                boxsample(previbuf, fx-minx+dxt[0], fy-miny+dxt[1], fx+minx+dxt[0], fy+miny+dxt[1], &texr, imaprepeat, imapextend);
                val2= dy*val2+ dx*(texr.tr + texr.tg + texr.tb);
                boxsample(previbuf, fx-minx+dyt[0], fy-miny+dyt[1], fx+minx+dyt[0], fy+miny+dyt[1], &texr, imaprepeat, imapextend);
                val3= dy*val3+ dx*(texr.tr + texr.tg + texr.tb);
                
                texres->nor[0]= (val1-val2);    /* vals have been interpolated above! */
                texres->nor[1]= (val1-val3);
                
                if(dx<1.0f) {
                    dy= 1.0f-dx;
                    texres->tb= dy*texres->tb+ dx*texr.tb;
                    texres->tg= dy*texres->tg+ dx*texr.tg;
                    texres->tr= dy*texres->tr+ dx*texr.tr;
                    texres->ta= dy*texres->ta+ dx*texr.ta;
                }
            }
            texres->nor[0]*= bumpscale;
            texres->nor[1]*= bumpscale;
        }
        else {
            maxx= fx+minx;
            minx= fx-minx;
            maxy= fy+miny;
            miny= fy-miny;

            boxsample(curibuf, minx, miny, maxx, maxy, texres, imaprepeat, imapextend);

            if(previbuf!=curibuf) {  /* interpolate */
                boxsample(previbuf, minx, miny, maxx, maxy, &texr, imaprepeat, imapextend);
                
                fx= 2.0f*(pixsize-maxd)/pixsize;
                
                if(fx>=1.0f) {
                    texres->ta= texr.ta; texres->tb= texr.tb;
                    texres->tg= texr.tg; texres->tr= texr.tr;
                } else {
                    fy= 1.0f-fx;
                    texres->tb= fy*texres->tb+ fx*texr.tb;
                    texres->tg= fy*texres->tg+ fx*texr.tg;
                    texres->tr= fy*texres->tr+ fx*texr.tr;
                    texres->ta= fy*texres->ta+ fx*texr.ta;
                }
            }
        }
    }
    else {
        const int intpol = tex->imaflag & TEX_INTERPOL;
        if (intpol) {
            /* sample 1 pixel minimum */
            if (minx < 0.5f / ibuf->x) minx = 0.5f / ibuf->x;
            if (miny < 0.5f / ibuf->y) miny = 0.5f / ibuf->y;
        }

        if(texres->nor && (tex->imaflag & TEX_NORMALMAP)==0) {
            boxsample(ibuf, fx-minx, fy-miny, fx+minx, fy+miny, texres, imaprepeat, imapextend);
            val1= texres->tr+texres->tg+texres->tb;
            boxsample(ibuf, fx-minx+dxt[0], fy-miny+dxt[1], fx+minx+dxt[0], fy+miny+dxt[1], &texr, imaprepeat, imapextend);
            val2= texr.tr + texr.tg + texr.tb;
            boxsample(ibuf, fx-minx+dyt[0], fy-miny+dyt[1], fx+minx+dyt[0], fy+miny+dyt[1], &texr, imaprepeat, imapextend);
            val3= texr.tr + texr.tg + texr.tb;

            /* don't switch x or y! */
            texres->nor[0]= (val1-val2);
            texres->nor[1]= (val1-val3);
        }
        else
            boxsample(ibuf, fx-minx, fy-miny, fx+minx, fy+miny, texres, imaprepeat, imapextend);
    }
    
    if(tex->imaflag & TEX_CALCALPHA) {
        texres->ta= texres->tin= texres->ta*MAX3(texres->tr, texres->tg, texres->tb);
    }
    else texres->tin= texres->ta;

    if(tex->flag & TEX_NEGALPHA) texres->ta= 1.0f-texres->ta;
    
    if( (R.flag & R_SEC_FIELD) && (ibuf->flags & IB_fields) ) {
        ibuf->rect-= (ibuf->x*ibuf->y);
    }

    if(texres->nor && (tex->imaflag & TEX_NORMALMAP)) {
        // qdn: normal from color
        // The invert of the red channel is to make
        // the normal map compliant with the outside world.
        // It needs to be done because in Blender
        // the normal used in the renderer points inward. It is generated
        // this way in calc_vertexnormals(). Should this ever change
        // this negate must be removed.
        texres->nor[0] = -2.f*(texres->tr - 0.5f);
        texres->nor[1] = 2.f*(texres->tg - 0.5f);
        texres->nor[2] = 2.f*(texres->tb - 0.5f);
    }
    
    /* de-premul, this is being premulled in shade_input_do_shade() */
    if(texres->ta!=1.0f && texres->ta>1e-4f) {
        fx= 1.0f/texres->ta;
        texres->tr*= fx;
        texres->tg*= fx;
        texres->tb*= fx;
    }

    BRICONTRGB;
    
    return retval;
}

void image_sample(Image *ima, float fx, float fy, float dx, float dy, float *result)
{
    TexResult texres;
    ImBuf *ibuf= BKE_image_get_ibuf(ima, NULL);
    
    if(ibuf==NULL) {
        result[0]= result[1]= result[2]= result[3]= 0.0f;
        return;
    }
    
    if( (R.flag & R_SEC_FIELD) && (ibuf->flags & IB_fields) )
        ibuf->rect+= (ibuf->x*ibuf->y);

    texres.talpha= 1; /* boxsample expects to be initialized */
    boxsample(ibuf, fx, fy, fx+dx, fy+dy, &texres, 0, 1);
    result[0]= texres.tr;
    result[1]= texres.tg;
    result[2]= texres.tb;
    result[3]= texres.ta;
    
    if( (R.flag & R_SEC_FIELD) && (ibuf->flags & IB_fields) )
        ibuf->rect-= (ibuf->x*ibuf->y);
}

void ibuf_sample(ImBuf *ibuf, float fx, float fy, float dx, float dy, float *result)
{
    TexResult texres;
    afdata_t AFD;
    
    if(ibuf==NULL) {
        return;
    }
    
    AFD.dxt[0] = dx; AFD.dxt[1] = dx;
    AFD.dyt[0] = dy; AFD.dyt[1] = dy;
    //copy_v2_v2(AFD.dxt, dx);
    //copy_v2_v2(AFD.dyt, dy);
    
    AFD.intpol = 1;
    AFD.extflag = TXC_EXTD;
    
    memset(&texres, 0, sizeof(texres));
    ewa_eval(&texres, ibuf, fx, fy, &AFD);
    
    
    result[0]= texres.tr;
    result[1]= texres.tg;
    result[2]= texres.tb;
    result[3]= texres.ta;
}