From 7de098e11d6c04812fcc0e8b4ace3f8f921c7c96 Mon Sep 17 00:00:00 2001
From: Rudolf Polzer <divverent@alientrap.org>
Date: Sat, 16 Apr 2011 20:04:05 +0200
Subject: [PATCH] add a highpass feature too

---
 misc/tools/fft-normalmap-to-heightmap.c | 31 ++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/misc/tools/fft-normalmap-to-heightmap.c b/misc/tools/fft-normalmap-to-heightmap.c
index 78e7e020..c9368674 100644
--- a/misc/tools/fft-normalmap-to-heightmap.c
+++ b/misc/tools/fft-normalmap-to-heightmap.c
@@ -35,7 +35,7 @@
 
 #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)
+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 x, y;
 	int i, j;
@@ -106,6 +106,10 @@ void nmap_to_hmap(unsigned char *map, const unsigned char *refmap, int w, int h,
 	{
 		fx = x * 1.0 / w;
 		fy = y * 1.0 / h;
+		if(fx > 0.5)
+			fx -= 1;
+		if(fy > 0.5)
+			fy -= 1;
 		if(filter)
 		{
 			// discontinous case
@@ -168,10 +172,6 @@ void nmap_to_hmap(unsigned char *map, const unsigned char *refmap, int w, int h,
 		else
 		{
 			// continuous integration case
-			if(fx > 0.5)
-				fx -= 1;
-			if(fy > 0.5)
-				fy -= 1;
 			/* these must have the same sign as fx and fy (so ffx*fx + ffy*fy is nonzero), otherwise do not matter */
 			/* it basically decides how artifacts are distributed */
 			ffx = fx;
@@ -193,6 +193,22 @@ void nmap_to_hmap(unsigned char *map, const unsigned char *refmap, int w, int h,
 				freqspace1[(w*y+x)][0] = 0;
 				freqspace1[(w*y+x)][1] = 0;
 			}
+#endif
+		}
+		if(highpass > 0)
+		{
+			double f1 = (fabs(fx)*highpass);
+			double f2 = (fabs(fy)*highpass);
+			// if either of them is < 1, phase out (min at 0.5)
+			double f =
+				(f1 <= 0.5 ? 0 : (f1 >= 1 ? 1 : ((f1 - 0.5) * 2.0)))
+				*
+				(f2 <= 0.5 ? 0 : (f2 >= 1 ? 1 : ((f2 - 0.5) * 2.0)));
+#ifdef C99
+			freqspace1[(w*y+x)] *= f;
+#else
+			freqspace1[(w*y+x)][0] *= f;
+			freqspace1[(w*y+x)][1] *= f;
 #endif
 		}
 	}
@@ -1034,6 +1050,7 @@ int main(int argc, char **argv)
 	double scale, offset;
 	int nmaplen, w, h;
 	int renormalize = 0;
+	double highpass = 0;
 	unsigned char *nmapdata, *nmap, *refmap;
 	const char *filtertype;
 	const double *filter = NULL;
@@ -1079,6 +1096,8 @@ int main(int argc, char **argv)
 
 	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"));
 
 	nmapdata = FS_LoadFile(infile, &nmaplen);
 	if(!nmapdata)
@@ -1141,7 +1160,7 @@ 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);
+		nmap_to_hmap(nmap, refmap, image_width, image_height, scale, offset, filter, filterw, filterh, renormalize, highpass);
 
 	if(!Image_WriteTGABGRA(outfile, image_width, image_height, nmap))
 	{
-- 
2.39.2