From 52af6ac17380e89769af405a5adc83086c9d00f0 Mon Sep 17 00:00:00 2001
From: Robin B <robin@broda.me>
Date: Thu, 25 Oct 2018 18:56:59 +0200
Subject: [PATCH] radial: configurable offsets (#73)

* Add: Offset radial visualizer (config)

* Add: Offset radial visualizer
---
 shaders/radial.glsl   | 4 ++++
 shaders/radial/1.frag | 4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/shaders/radial.glsl b/shaders/radial.glsl
index 3d3269b..1261b9b 100644
--- a/shaders/radial.glsl
+++ b/shaders/radial.glsl
@@ -27,6 +27,10 @@
    the background. */
 #define BAR_ALIAS_FACTOR 1.2
 #define C_ALIAS_FACTOR 1.8
+/* Offset (Y) of the visualization */
+#define CENTER_OFFSET_Y 0
+/* Offset (X) of the visualization */
+#define CENTER_OFFSET_X 0
 
 /* Gravity step, overrude frin `smooth_parameters.glsl` */
 #request setgravitystep 5.0
diff --git a/shaders/radial/1.frag b/shaders/radial/1.frag
index 65c6c10..29c0e88 100644
--- a/shaders/radial/1.frag
+++ b/shaders/radial/1.frag
@@ -41,8 +41,8 @@ void main() {
        Alpha layer blending is only applied when `xroot` transparency is enabled. */
     
     float /* translate (x, y) to use (0, 0) as the center of the screen */
-        dx = gl_FragCoord.x - (screen.x / 2),
-        dy = gl_FragCoord.y - (screen.y / 2);
+        dx = gl_FragCoord.x - (screen.x / 2) + CENTER_OFFSET_X,
+        dy = gl_FragCoord.y - (screen.y / 2) + CENTER_OFFSET_Y;
     float theta = atan(dy, dx); /* fragment angle with the center of the screen as the origin */
     float d = sqrt((dx * dx) + (dy * dy)); /* distance */
     if (d > C_RADIUS - (float(C_LINE) / 2.0F) && d < C_RADIUS + (float(C_LINE) / 2.0F)) {