Rotation causing divide-by-zero

Vertex.glsl

    #version 410\n\
    \
    uniform vec2 TS_Offset;\n\
    uniform vec2 TS_RotationOffset;\n\
    uniform float TS_RotationAngle;\n\
    \
    in vec2 TS_TextureUV;\n\
    in vec4 TS_Position;\n\
    in vec4 TS_Color;\n\
    \
    out vec4 color_v;\n\
    out vec2 tex_v;\n\
    \
    uniform vec2 TS_ScreenSize;\n\
    \
    void main (void)\n\
    {\n\
        tex_v = TS_TextureUV;\n\
        color_v = TS_Color;\n\
        //Rotation: \n\
        vec2 TS_Distance = (TS_Position.xy - TS_RotationOffset) + 0.001;\n\
        float TS_ModAngle = atan(TS_Distance.y, TS_Distance.x) + TS_RotationAngle;\n\
        float TS_Distance2 = sqrt( (TS_Distance.x*TS_Distance.x) * (TS_Distance.y*TS_Distance.y));\n\
        vec2 TS_NewPos = (TS_RotationOffset + vec2( cos(TS_ModAngle), sin(TS_ModAngle) ) * TS_Distance2 )*2.0;\n\
        gl_Position = (vec4(TS_Offset.x*2.0, TS_Offset.y*(-2.0), 0.0, 0.0) +(vec4(TS_NewPos.x - TS_ScreenSize.x, -TS_NewPos.y + (TS_ScreenSize.y), TS_Position.ba)))/vec4(TS_ScreenSize, 1.0, 1.0);\n\
    }\