Vertex ordering problem

So I’m nearly finished with a project except I’m trying to apply a 2D color gradient to a hemisphere (Dome) object and I cannot figure out how vertices are ordered at all. When I use the below code it colors it from red, orange, to green from the bottom of the dome to the top. However, I need to split the Dome in 2 and shade down both halves from the Dome’s center. Anyone have any idea how to do this or know where the layout of vertices for a Dome is documented?

pre type="java"
for(int k = 0; k < vertexCount; k++){

            m_full_color_array[colorIndex++]= 1.0f - ((1.0f / ((float) steps))*k);

            m_full_color_array[colorIndex++]= ((1.0f / ((float) steps))*k);

            m_full_color_array[colorIndex++]= 0.0f;

            m_full_color_array[colorIndex++]= 0.0f;