// vshader
 precision mediump float;
 attribute vec4 vPosition;   // value from application program
 attribute float vertexTemp; // from application program
 varying float temperature;  // value to be sent to fragment shader

 void main(void)
 {
  // normalize temperature to [0, 1]
   temperature = ( vertexTemp - 0 ) / 50;
    gl_Position = vPosition;
 }
 
