From d2b38b16b1c416e160f5442cbcef64d1dd97f5f5 Mon Sep 17 00:00:00 2001
From: Lars-Dominik Braun <lars@6xq.net>
Date: Thu, 28 May 2015 17:35:46 +0200
Subject: random: Remove symmetry bias

---
 flam3.c  | 23 ++---------------------
 flam3.h  |  2 +-
 main.c   |  7 ++++++-
 parser.c |  2 +-
 4 files changed, 10 insertions(+), 24 deletions(-)

diff --git a/flam3.c b/flam3.c
index ea8a51f..e0e014f 100644
--- a/flam3.c
+++ b/flam3.c
@@ -1320,34 +1320,15 @@ static int compare_xforms(const void *av, const void *bv) {
 }
 
 /* sym=2 or more means rotational
-   sym=1 means identity, ie no symmetry
-   sym=0 means pick a random symmetry (maybe none)
+   sym=1 and sym=0 means identity, ie no symmetry
    sym=-1 means bilateral (reflection)
    sym=-2 or less means rotational and reflective
 */
-void flam3_add_symmetry(flam3_genome *cp, int sym, randctx * const rc) {
+void flam3_add_symmetry(flam3_genome *cp, int sym) {
    int i, j, k;
    double a;
    int result = 0;
 
-   if (0 == sym) {
-      static int sym_distrib[] = {
-         -4, -3,
-         -2, -2, -2,
-         -1, -1, -1,
-         2, 2, 2,
-         3, 3,
-         4, 4,
-      };
-      if (rand_bool(rc)) {
-         sym = rand_distrib(rc, sym_distrib);
-      } else if (rand_mod(rc, 32)) {
-         sym = rand_mod(rc, 13)-6;
-      } else {
-         sym = rand_mod(rc, 51)-25;
-      }
-   }
-
    if (1 == sym || 0 == sym) return;
 
    cp->symmetry = sym;
diff --git a/flam3.h b/flam3.h
index 488c963..e7596d7 100644
--- a/flam3.h
+++ b/flam3.h
@@ -457,7 +457,7 @@ void flam3_cross(flam3_genome *cp0, flam3_genome *cp1, flam3_genome *out, int cr
 /* return NULL in case of error */
 flam3_genome *flam3_parse_xml2(const int, int default_flag, int *ncps, randctx * const);
 
-void flam3_add_symmetry(flam3_genome *cp, int sym, randctx * const rc);
+void flam3_add_symmetry(flam3_genome *cp, int sym);
 
 void flam3_improve_colors(flam3_genome *g, unsigned int ntries,
 		bool change_palette,
diff --git a/main.c b/main.c
index ec6205d..8bf0e6c 100644
--- a/main.c
+++ b/main.c
@@ -145,6 +145,7 @@ static void print_genome (flam3_genome * const genome) {
 typedef struct {
 	const char *palette;
 	unsigned int width, height, max_xforms, max_var;
+	signed int max_symmetry, min_symmetry;
 	double post_likelihood, final_likelihood, symmetry_likelihood;
 } random_arguments;
 
@@ -277,7 +278,9 @@ static void do_random (const random_arguments * const arguments) {
 
 	/* Randomly add symmetry (but not if we've already added a final xform) */
 	if (rand_d01(&rc) < arguments->symmetry_likelihood && !add_final) {
-		flam3_add_symmetry(&genome, 0, &rc);
+		assert (arguments->max_symmetry >= arguments->min_symmetry);
+		unsigned int symrange = arguments->max_symmetry - arguments->min_symmetry + 1;
+		flam3_add_symmetry(&genome, rand_mod (&rc, symrange) + arguments->min_symmetry);
 	}
 
 	/* random resets genome, adjust before finding appropriate bbox */
@@ -635,6 +638,8 @@ int main (int argc, char **argv) {
 				.post_likelihood = 0.4,
 				.final_likelihood = 0.15,
 				.symmetry_likelihood = 0.25,
+				.min_symmetry = -6,
+				.max_symmetry = 6,
 				};
 
 		argp_parse (&argp, argc, argv, 0, NULL, &arguments);
diff --git a/parser.c b/parser.c
index 1c8e060..25e1701 100644
--- a/parser.c
+++ b/parser.c
@@ -603,7 +603,7 @@ static int parse_flame_element(xmlNode *flame_node, flam3_genome *loc_current_cp
          }
 
          bef = cp->num_xforms;
-         flam3_add_symmetry(cp,kind, rc);
+         flam3_add_symmetry(cp, kind);
          aft = cp->num_xforms;
          num_std_xforms += (aft-bef);
          
-- 
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