commit 44efc8a8012ccc1d2caa44e39158946be4d31e1f
Author: Leszek Koltunski <leszek@distoretedandroid.org>
Date:   Thu Nov 24 14:15:43 2016 +0000

    Improve the Deform app

diff --git a/src/main/res/raw/main_vertex_shader.glsl b/src/main/res/raw/main_vertex_shader.glsl
index 14d5449..fcaef9f 100644
--- a/src/main/res/raw/main_vertex_shader.glsl
+++ b/src/main/res/raw/main_vertex_shader.glsl
@@ -234,7 +234,7 @@ void deform(in int effect, inout vec4 v)
   float denomV = 1.0 / (aForce.y + Aw.x);
   float denomH = 1.0 / (aForce.x + Aw.y);
 
-  vec2 vertCorr= ONE - aPS / ( aForce+C*aPS + (ONE-sign(aForce)) );
+  vec2 vertCorr= ONE - aPS / ( aForce+C*aPS + (ONE-sign(aForce)) );  // avoid division by 0 when force and PS both are 0
 
   float mvXvert = -B * ps.x * aForce.y * (1.0-quot.y) * denomV;      // impact the vertical   component of the force vector has on horizontal movement
   float mvYhorz = -B * ps.y * aForce.x * (1.0-quot.x) * denomH;      // impact the horizontal component of the force vector has on vertical   movement