#version 300 es
precision mediump float;
uniform mat4 modelMat;
uniform mat4 viewMat;
uniform mat4 projMat;
uniform float pointSize;
layout(location = 0) in vec4 pos;
out float _alphaFac;
void main()
{
    gl_Position =   projMat*viewMat*modelMat*vec4(pos.xyz,1.0);
    gl_PointSize = (1.0-gl_Position.z/gl_Position.w)*pointSize;
    _alphaFac = pos.w;
}