Import asteria from jwildfire

7 files changed, 71 insertions, 2 deletions

diff --git a/flam3.c b/flam3.c
index e0e014f..9bb8130 100644
--- a/flam3.c
+++ b/flam3.c
@@ -484,6 +484,8 @@ void flam3_copy_params(flam3_xform * restrict dest, flam3_xform * restrict src,
       dest->mobius_im_b = src->mobius_im_b;
       dest->mobius_im_c = src->mobius_im_c;
       dest->mobius_im_d = src->mobius_im_d;
+   } else if (varn==VAR_ASTERIA) {
+      dest->asteria_alpha = src->asteria_alpha;
    }
 }
 
@@ -1238,6 +1240,10 @@ static void flam3_print_xform(FILE *f, flam3_xform *x, int final_flag,
 					fprintf(f, "mobius_im_d=\"%g\" ", x->mobius_im_d);
 					break;
 
+				case VAR_ASTERIA:
+					fprintf(f, "asteria_alpha=\"%g\" ", x->asteria_alpha);
+					break;
+
 				case VAR_SEPARATION:
 					fprintf(f, "separation_x=\"%g\" ", x->separation_x);
 					fprintf(f, "separation_y=\"%g\" ", x->separation_y);
diff --git a/flam3.h b/flam3.h
index 9d36ebf..8415974 100644
--- a/flam3.h
+++ b/flam3.h
@@ -30,7 +30,7 @@
 
 extern char *flam3_variation_names[];
 
-#define flam3_nvariations 99
+#define flam3_nvariations 100
 
 #define flam3_interpolation_linear 0
 #define flam3_interpolation_smooth 1
@@ -144,6 +144,7 @@ typedef enum {
 #define VAR_AUGER 96
 #define VAR_FLUX 97
 #define VAR_MOBIUS 98
+#define VAR_ASTERIA 99
 
 #include "vector.h"
 #include "random.h"
@@ -366,6 +367,11 @@ typedef struct xform {
    double super_shape_pm_4;
    double super_shape_pneg1_n1;
 
+   /* asteria */
+   double asteria_alpha;
+   /* precalc */
+   double asteria_sina, asteria_cosa;
+
    int num_active_vars;
    double active_var_weights[flam3_nvariations];
    int varFunc[flam3_nvariations];
diff --git a/genome.c b/genome.c
index f4ccc8e..1a063af 100644
--- a/genome.c
+++ b/genome.c
@@ -253,6 +253,10 @@ static void random_xform_param (flam3_xform * const xform, const unsigned int i,
 			xform->mobius_re_d = rand_d11(rc);
 			xform->mobius_im_d = rand_d11(rc);
 			break;
+
+		case VAR_ASTERIA:
+			xform->asteria_alpha = rand_d01(rc);
+			break;
 	}
 }
 
diff --git a/interpolation.c b/interpolation.c
index 5fa1e07..4eae663 100644
--- a/interpolation.c
+++ b/interpolation.c
@@ -472,6 +472,7 @@ void flam3_interpolate_n(flam3_genome *result, int ncp,
       INTERP(xform[i].mobius_im_c);
       INTERP(xform[i].mobius_re_d);
       INTERP(xform[i].mobius_im_d);
+      INTERP(xform[i].asteria_alpha);
 
       for (j = 0; j < flam3_nvariations; j++)
          INTERP(xform[i].var[j]);
diff --git a/math.h b/math.h
index 48519b4..c29e427 100644
--- a/math.h
+++ b/math.h
@@ -109,6 +109,18 @@ inline double sum(const double2 in) {
 	return in[0] + in[1];
 }
 
+inline double square (const double in) {
+	return in * in;
+}
+
+inline double2 square_d2 (const double2 in) {
+	return in * in;
+}
+
+inline double squaresum (const double2 in) {
+	return sum (square_d2 (in));
+}
+
 inline void normalize (double * const a, const size_t n) {
 	double sum = 0.0;
 	for (unsigned int j = 0; j < n; j++) {
diff --git a/parser.c b/parser.c
index 25e1701..d99dfe8 100644
--- a/parser.c
+++ b/parser.c
@@ -1085,6 +1085,8 @@ static int parse_xform_xml(xmlNode *chld_node,flam3_xform *this_xform, int *num_
          this_xform->mobius_im_c = flam3_atof(att_str);
       } else if (!xmlStrcmp(cur_att->name, (const xmlChar *)"Im_D") || !xmlStrcmp(cur_att->name, (const xmlChar *)"mobius_im_d")) {
          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 {
          int v = var2n((char *) cur_att->name);
          if (v != flam3_variation_none)
diff --git a/variations.c b/variations.c
index f42c623..caf661b 100644
--- a/variations.c
+++ b/variations.c
@@ -129,6 +129,7 @@ char *flam3_variation_names[1+flam3_nvariations] = {
   "auger",
   "flux",
   "mobius",
+  "asteria",
   0
 };
 
@@ -1829,6 +1830,35 @@ static double2 var98_mobius (const double2 in, const flam3_iter_helper * const f
 	return rad_v * (double2) { (re_u*re_v + im_u*im_v), (im_u*re_v - re_u*im_v) };
 }
 
+static double2 var99_asteria (const double2 in, const flam3_iter_helper * const f, double weight) {
+	/* from jwildfire: asteria by dark-beam,
+	 * http://jwildfire.org/forum/viewtopic.php?f=23&t=1464 */
+	const double2 w = weight * in;
+	double r = squaresum (in);
+	double xx = square (fabs(in[0]) - 1.);
+	double yy = square (fabs(in[1]) - 1.);
+	const double r2 = sqrt(yy + xx);
+	bool in1 = r < 1.;
+	const bool out2 = r2 < 1.;
+	if (in1 && out2) {
+		in1 = rand_d01 (f->rc) > 0.35;
+	} else {
+		in1 = !in1;
+	}
+
+	if (in1) {
+		return var0_linear (in, f, weight);
+	} else {
+		const double sina = f->xform->asteria_sina;
+		const double cosa = f->xform->asteria_cosa;
+		xx = w[0] * cosa - w[1] * sina;
+		yy = w[0] * sina + w[1] * cosa;
+		const double nx = xx / sqrt(1. - yy * yy) * (1. - sqrt(1. - square(-fabs(yy) + 1.)));
+		xx = nx * cosa + yy * sina;
+		yy = -nx * sina + yy * cosa;
+		return (double2) { xx, yy };
+	}
+}
 
 /* Precalc functions */
 
@@ -1892,6 +1922,11 @@ static void supershape_precalc(flam3_xform *xf) {
    xf->super_shape_pneg1_n1 = -1.0 / xf->super_shape_n1;
 }
 
+static void asteria_precalc (flam3_xform * const xf) {
+	xf->asteria_sina = sin (M_PI * xf->asteria_alpha);
+	xf->asteria_cosa = cos (M_PI * xf->asteria_alpha);
+}
+
 /*	Precalculate constants (i.e. not depending on position) for variations
  */
 void xform_precalc (flam3_xform * const xform) {
@@ -1903,6 +1938,7 @@ void xform_precalc (flam3_xform * const xform) {
    disc2_precalc(xform);
    supershape_precalc(xform);
    wedgeJulia_precalc(xform);
+   asteria_precalc (xform);
 }
 
 static double adjust_percentage(double in) {
@@ -2013,7 +2049,7 @@ int prepare_precalc_flags(flam3_genome *cp) {
                xf->precalc_atan_yx_flag=1;
             } else if (j==VAR_LOG) {
                xf->precalc_atan_yx_flag=1;
-            }
+			}
 
             totnum++;
          }
@@ -2264,6 +2300,8 @@ int apply_xform(const flam3_xform * const xf, const double4 p, double4 *q_ret,
 				accum += var97_flux(t, &f, weight); break;
 			case (VAR_MOBIUS):
 				accum += var98_mobius(t, &f, weight); break;
+			case VAR_ASTERIA:
+				accum += var99_asteria (t, &f, weight); break;
 		}
 
 	}