uniform mat4 m;
uniform mat4 v;
uniform mat4 p;
attribute vec3 pos;
attribute vec2 normale;
void main()
{
     float linewidth = 4.0;
     mat4 mv = v * m;
     vec4 delta = vec4(linewidth * normale.x, linewidth * normale.y, 0.0,0.0);
     vec4 pos2 = mv * vec4(pos.xy, 0.0, 1.0) ;
   gl_Position = p * (pos2 + delta);
}

for (int i = 0, valuesLength = values.length; i < valuesLength; i++) {//todo do not allocate
     float value = (float) values[i] / maxValue; // make it [0:1]
     Vertex v1 = new Vertex();//todo rewrite without allocatinos
     Vertex v2 = new Vertex();//todo rewrite without allocatinos
     float x = i;
     float y = value;
     if (vertices.size() > 0) {
         // copy normale vecotrs from prev vertices
         Vertex t1 = new Vertex();
         Vertex t2 = new Vertex();
         t1.x = x;
         t1.y = y;
         t1.z = 1;
         t1.normale_x = vertices.get(vertices.size() - 2).normale_x;
         t1.normale_y = vertices.get(vertices.size() - 2).normale_y;
         t2.x = x;
         t2.y = y;
         t2.z = -1;
         t2.normale_x = vertices.get(vertices.size() - 1).normale_x;
         t2.normale_y = vertices.get(vertices.size() - 1).normale_y;
         vertices.add(t1);
         vertices.add(t2);
     }
     v1.x = x ;
     v1.y = y ;
     v1.z = 1;

     v2.x = x;
     v2.y = y;
     v2.z = -1;

     vertices.add(v1);
     vertices.add(v2);


     if (i == valuesLength - 1) {
         int j = i - 1;
         //todo last vertex
     } else {
         double nextValue = (float) values[i + 1] / column.maxValue;
         double dy = nextValue - value;
         double l = (float) Math.sqrt(1f + dy * dy);
         dy /= l;
         double dx = 1f / l;

         v1.normale_x = (float) -dy * 10;
         v1.normale_y = (float) dx;
         v2.normale_x = (float) dy * 10;
         v2.normale_y = (float) -dx;
     }
}

Matrix.orthoM(PROJ, 0, 0, w, 0, h, -1.0f, 1.0f);

Matrix.setIdentityM(MODEL, 0);
Matrix.scaleM(MODEL, 0, mywpx/(float)maxXValue, myhpx , 1.0f);

Matrix.setIdentityM(VIEW, 0);
Matrix.translateM(VIEW, 0, dxpx, dypx ,0);

GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, vertices.size());