precision mediump float;

​

attribute vec3 aPosition;

uniform mat4 uModelMatrix;

uniform mat4 uModelViewMatrix;

uniform mat4 uProjectionMatrix;

varying float vDistance;

​

uniform vec3 uReferencePoint; // Add uniform for the reference point

varying vec3 vWorldPosition; // Pass world position to fragment shader

​

void main() {

    vec4 worldPosition = uModelMatrix * vec4(aPosition, 1.0);

    gl_Position = uProjectionMatrix * uModelViewMatrix * vec4(aPosition, 1.0);

​

    // Pass world position to fragment shader

    vWorldPosition = worldPosition.xyz;

}