#version 420

in layout(location=0) vec3 position; /* vertex position in model coordinates */
in layout(location=1) vec2 offset; /* xy coordinates offset for atlases */
in layout(location=2) mat4 M_MVP;

out vec2 Fragment_UV; /* UV coordinates for the fragment */

uniform float number_of_rows; /* For texture atlases */

void main()
{
    gl_Position = M_MVP * vec4(position, 1.0);

    Fragment_UV = position.xy + vec2(0.5, 0.5);
    Fragment_UV.y = 1.0 - Fragment_UV.y;
    Fragment_UV = (Fragment_UV / number_of_rows ) + offset;
}