normal/heightmap tool: allow setting the bias relatively to the median

diff --git a/misc/tools/fft-normalmap-to-heightmap.c b/misc/tools/fft-normalmap-to-heightmap.c
index c5b5ea5f8a2a8ff88b849cbe78ca52c0087060e5..e025150b64448bdc2404e489cd1a1cadcedaa229 100644 (file)
--- a/misc/tools/fft-normalmap-to-heightmap.c
+++ b/misc/tools/fft-normalmap-to-heightmap.c
@@ -35,7 +35,18 @@
 
 #define TWO_PI (4*atan2(1,1) * 2)
 
-void nmap_to_hmap(unsigned char *map, const unsigned char *refmap, int w, int h, double scale, double offset, const double *filter, int filterw, int filterh, int renormalize, double highpass)
+int floatcmp(const void *a_, const void *b_)
+{
+       float a = *(float *)a_;
+       float b = *(float *)b_;
+       if(a < b)
+               return -1;
+       if(a > b)
+               return +1;
+       return 0;
+}
+
+void nmap_to_hmap(unsigned char *map, const unsigned char *refmap, int w, int h, double scale, double offset, const double *filter, int filterw, int filterh, int renormalize, double highpass, int use_median)
 {
        int x, y;
        int i, j;
@@ -294,6 +305,38 @@ void nmap_to_hmap(unsigned char *map, const unsigned char *refmap, int w, int h,
                scale = 2 / (vmax - vmin);
                offset = -(vmax + vmin) / (vmax - vmin);
        }
+       else if(use_median)
+       {
+               // negative scale = match median to offset
+
+               fprintf(stderr, "Calculating median...\n");
+
+               float *medianbuf = malloc(sizeof(float) * w * h);
+               float vmed;
+
+               fprintf(stderr, "  converting...\n");
+               /* renormalize, find min/max */
+               for(y = 0; y < h; ++y)
+               for(x = 0; x < w; ++x)
+               {
+#ifdef C99
+                       v = creal(imgspace1[(w*y+x)]);
+#else
+                       v = (imgspace1[(w*y+x)][0]);
+#endif
+                       medianbuf[w*y+x] = v;
+               }
+               fprintf(stderr, "  sorting...\n");
+               qsort(medianbuf, w*h, sizeof(*medianbuf), floatcmp);
+               fprintf(stderr, "  done.\n");
+               if(w*h % 2)
+                       vmed = medianbuf[(w*h-1)/2];
+               else
+                       vmed = (medianbuf[(w*h)/2] + medianbuf[(w*h-2)/2]) * 0.5;
+
+               // we actually want (v - vmed) * scale + offset
+               offset -= vmed * scale;
+       }
 
        printf("Min: %f\nAvg: %f\nMax: %f\nScale: %f\nOffset: %f\nScaled-Min: %f\nScaled-Avg: %f\nScaled-Max: %f\n", 
                vmin, 0.0, vmax, scale, offset, vmin * scale + offset, offset, vmax * scale + offset);
@@ -1049,6 +1092,7 @@ int main(int argc, char **argv)
        const char *infile, *outfile, *reffile;
        double scale, offset;
        int nmaplen, w, h;
+       int use_median = 0;
        int renormalize = 0;
        double highpass = 0;
        unsigned char *nmapdata, *nmap, *refmap;
@@ -1094,10 +1138,13 @@ int main(int argc, char **argv)
        else
                reffile = NULL;
 
+       // experimental features
        if(getenv("FFT_NORMALMAP_TO_HEIGHTMAP_RENORMALIZE"))
                renormalize = atoi(getenv("FFT_NORMALMAP_TO_HEIGHTMAP_RENORMALIZE"));
        if(getenv("FFT_NORMALMAP_TO_HEIGHTMAP_HIGHPASS"))
                highpass = atof(getenv("FFT_NORMALMAP_TO_HEIGHTMAP_HIGHPASS"));
+       if(getenv("FFT_NORMALMAP_TO_HEIGHTMAP_USE_MEDIAN"))
+               use_median = atof(getenv("FFT_NORMALMAP_TO_HEIGHTMAP_USE_MEDIAN"));
 
        nmapdata = FS_LoadFile(infile, &nmaplen);
        if(!nmapdata)
@@ -1160,7 +1207,7 @@ int main(int argc, char **argv)
                        hmap_to_nmap(nmap, image_width, image_height, -scale-1, offset);
        }
        else
-               nmap_to_hmap(nmap, refmap, image_width, image_height, scale, offset, filter, filterw, filterh, renormalize, highpass);
+               nmap_to_hmap(nmap, refmap, image_width, image_height, scale, offset, filter, filterw, filterh, renormalize, highpass, use_median);
 
        if(!Image_WriteTGABGRA(outfile, image_width, image_height, nmap))
        {