Import bcollide from jwildfire

6 files changed, 59 insertions, 2 deletions

diff --git a/flam3.c b/flam3.c
index 9bb8130..950fa82 100644
--- a/flam3.c
+++ b/flam3.c
@@ -486,6 +486,9 @@ void flam3_copy_params(flam3_xform * restrict dest, flam3_xform * restrict src,
       dest->mobius_im_d = src->mobius_im_d;
    } else if (varn==VAR_ASTERIA) {
       dest->asteria_alpha = src->asteria_alpha;
+   } else if (varn==VAR_BCOLLIDE) {
+   	  dest->bcollide_num = src->bcollide_num;
+   	  dest->bcollide_a = src->bcollide_a;
    }
 }
 
@@ -1251,6 +1254,11 @@ static void flam3_print_xform(FILE *f, flam3_xform *x, int final_flag,
 					fprintf(f, "separation_yinside=\"%g\" ", x->separation_yinside);
 					break;
 
+				case VAR_BCOLLIDE:
+					fprintf(f, "bcollide_num=\"%g\" ", x->bcollide_num);
+					fprintf(f, "bcollide_a=\"%g\" ", x->bcollide_a);
+					break;
+
 				default:
 					/* pass */
 					break;
diff --git a/flam3.h b/flam3.h
index 8415974..b26c57a 100644
--- a/flam3.h
+++ b/flam3.h
@@ -30,8 +30,6 @@
 
 extern char *flam3_variation_names[];
 
-#define flam3_nvariations 100
-
 #define flam3_interpolation_linear 0
 #define flam3_interpolation_smooth 1
 
@@ -145,6 +143,8 @@ typedef enum {
 #define VAR_FLUX 97
 #define VAR_MOBIUS 98
 #define VAR_ASTERIA 99
+#define VAR_BCOLLIDE 100
+#define flam3_nvariations 101
 
 #include "vector.h"
 #include "random.h"
@@ -372,6 +372,11 @@ typedef struct xform {
    /* precalc */
    double asteria_sina, asteria_cosa;
 
+   /* bcollide */
+   double bcollide_num, bcollide_a;
+   /* precalc */
+   double bcollide_bCa, bcollide_bCn_pi, bcollide_bCa_bCn, bcollide_pi_bCn;
+
    int num_active_vars;
    double active_var_weights[flam3_nvariations];
    int varFunc[flam3_nvariations];
diff --git a/genome.c b/genome.c
index 1a063af..8221749 100644
--- a/genome.c
+++ b/genome.c
@@ -257,6 +257,11 @@ static void random_xform_param (flam3_xform * const xform, const unsigned int i,
 		case VAR_ASTERIA:
 			xform->asteria_alpha = rand_d01(rc);
 			break;
+
+		case VAR_BCOLLIDE:
+			xform->bcollide_num = rand_d01(rc)*(1<<16);
+			xform->bcollide_a = rand_d01(rc);
+			break;
 	}
 }
 
diff --git a/interpolation.c b/interpolation.c
index 4eae663..f665160 100644
--- a/interpolation.c
+++ b/interpolation.c
@@ -473,6 +473,8 @@ void flam3_interpolate_n(flam3_genome *result, int ncp,
       INTERP(xform[i].mobius_re_d);
       INTERP(xform[i].mobius_im_d);
       INTERP(xform[i].asteria_alpha);
+      INTERP(xform[i].bcollide_num);
+      INTERP(xform[i].bcollide_a);
 
       for (j = 0; j < flam3_nvariations; j++)
          INTERP(xform[i].var[j]);
diff --git a/parser.c b/parser.c
index d99dfe8..ca74577 100644
--- a/parser.c
+++ b/parser.c
@@ -1087,6 +1087,10 @@ static int parse_xform_xml(xmlNode *chld_node,flam3_xform *this_xform, int *num_
          this_xform->mobius_im_d = flam3_atof(att_str);
       } else if (!xmlStrcmp(cur_att->name, (const xmlChar *)"asteria_alpha")) {
          this_xform->asteria_alpha = flam3_atof(att_str);
+      } else if (!xmlStrcmp(cur_att->name, (const xmlChar *)"bcollide_num")) {
+         this_xform->bcollide_num = flam3_atof(att_str);
+      } else if (!xmlStrcmp(cur_att->name, (const xmlChar *)"bcollide_a")) {
+         this_xform->bcollide_a = flam3_atof(att_str);
       } else {
          int v = var2n((char *) cur_att->name);
          if (v != flam3_variation_none)
diff --git a/variations.c b/variations.c
index caf661b..00d49b7 100644
--- a/variations.c
+++ b/variations.c
@@ -130,6 +130,7 @@ char *flam3_variation_names[1+flam3_nvariations] = {
   "flux",
   "mobius",
   "asteria",
+  "bcollide",
   0
 };
 
@@ -1860,6 +1861,28 @@ static double2 var99_asteria (const double2 in, const flam3_iter_helper * const
 	}
 }
 
+static double2 var100_bcollide (const double2 in, const flam3_iter_helper * const f, double weight) {
+	/* from jwildfire: bCollide by Michael Faber,
+	 * http://michaelfaber.deviantart.com/art/bSeries-320574477 */
+	const flam3_xform *xf = f->xform;
+
+	const double tau = 0.5 * (log(square (in[0] + 1.0) + square (in[1])) - log(square (in[0] - 1.0) + square (in[1])));
+	double sigma = M_PI - atan2(in[1], in[0] + 1.0) - atan2(in[1], 1.0 - in[0]);
+
+	const int alt = (int) (sigma * xf->bcollide_bCn_pi);
+	if (alt % 2 == 0) {
+		sigma = alt * xf->bcollide_pi_bCn + fmod(sigma + xf->bcollide_bCa_bCn, xf->bcollide_pi_bCn);
+	} else {
+		sigma = alt * xf->bcollide_pi_bCn + fmod(sigma - xf->bcollide_bCa_bCn, xf->bcollide_pi_bCn);
+	}
+	const double sinht = sinh(tau);
+	const double cosht = cosh(tau);
+	double sins, coss;
+	sincos (sigma, &sins, &coss);
+	const double temp = cosht - coss;
+	return (double2) { weight * sinht / temp, weight * sins / temp };
+}
+
 /* Precalc functions */
 
 static void perspective_precalc(flam3_xform *xf) {
@@ -1927,6 +1950,13 @@ static void asteria_precalc (flam3_xform * const xf) {
 	xf->asteria_cosa = cos (M_PI * xf->asteria_alpha);
 }
 
+static void bcollide_precalc (flam3_xform * const xf) {
+    xf->bcollide_bCn_pi = xf->bcollide_num * M_1_PI;
+    xf->bcollide_pi_bCn = M_PI / xf->bcollide_num;
+    xf->bcollide_bCa = M_PI * xf->bcollide_a;
+    xf->bcollide_bCa_bCn = xf->bcollide_bCa / xf->bcollide_num;
+}
+
 /*	Precalculate constants (i.e. not depending on position) for variations
  */
 void xform_precalc (flam3_xform * const xform) {
@@ -1939,6 +1969,7 @@ void xform_precalc (flam3_xform * const xform) {
    supershape_precalc(xform);
    wedgeJulia_precalc(xform);
    asteria_precalc (xform);
+   bcollide_precalc (xform);
 }
 
 static double adjust_percentage(double in) {
@@ -2302,6 +2333,8 @@ int apply_xform(const flam3_xform * const xf, const double4 p, double4 *q_ret,
 				accum += var98_mobius(t, &f, weight); break;
 			case VAR_ASTERIA:
 				accum += var99_asteria (t, &f, weight); break;
+			case VAR_BCOLLIDE:
+				accum += var100_bcollide (t, &f, weight); break;
 		}
 
 	}