precision mediump float;

#endif

​

attribute vec3 aPosition;

​

// Always include this to get the position of the pixel and map the shader correctly onto the shape

​

void main() {

​

  // Copy the position data into a vec4, adding 1.0 as the w parameter

  vec4 positionVec4 = vec4(aPosition, 1.0);

​

  // Scale to make the output fit the canvas

  positionVec4.xy = positionVec4.xy * 2.0 - 1.0; 

​

  // Send the vertex information on to the fragment shader

  gl_Position = positionVec4;

}