#version 330 core
layout (location = 0) in vec2 vertex; // <vec2 pos>

out VS_OUT {
    vec2 texuv;
    flat int index;
} vs_out;

uniform mat4 transforms[400];
uniform mat4 projection;

void main()
{
    gl_Position = projection * transforms[gl_InstanceID] * vec4(vertex.xy, 0.0, 1.0);
    vs_out.index = gl_InstanceID;
    vs_out.texuv = vec2(vertex.x, 1.0f - vertex.y);
}