[hackers] [blind] blind-spiral-gradient: set the value of the singularity to 0 || Mattias Andrée

[git]

commit 484d84596ef059463d905f07c65672b92a38a28c
Author:     Mattias Andrée <maand...@kth.se>
AuthorDate: Tue Jul 11 19:18:56 2017 +0200
Commit:     Mattias Andrée <maand...@kth.se>
CommitDate: Tue Jul 11 19:18:56 2017 +0200

    blind-spiral-gradient: set the value of the singularity to 0
    
    Signed-off-by: Mattias Andrée <maand...@kth.se>

diff --git a/src/blind-spiral-gradient.c b/src/blind-spiral-gradient.c
index a248a02..8bdda44 100644
--- a/src/blind-spiral-gradient.c
+++ b/src/blind-spiral-gradient.c
@@ -66,12 +66,16 @@ static int with_vector;
                                y = (TYPE)iy - y1;\
                                for (ix = 0; ix < width; ix++) {\
                                        x = (TYPE)ix - x1;\
-                                       v = atan2(y, x);\
-                                       if (anticlockwise)\
-                                               v = 1 - v;\
-                                       v -= u;\
-                                       v += 4 * (TYPE)M_PI;\
-                                       v = mod(v, 2 * (TYPE)M_PI);\
+                                       if (!x && !y) {\
+                                               v = 0;\
+                                       } else {\
+                                               v = atan2(y, x);\
+                                               if (anticlockwise)\
+                                                       v = 1 - v;\
+                                               v -= u;\
+                                               v += 4 * (TYPE)M_PI;\
+                                               v = mod(v, 2 * (TYPE)M_PI);\
+                                       }\
                                        if (!with_vector) {\
                                                r = sqrt(x * x + y * y);\
                                        } else {\