#version 460
#extension GL_EXT_nonuniform_qualifier : require
#extension GL_EXT_scalar_block_layout : require
#extension GL_EXT_shader_16bit_storage : require

out Varyings {
    layout(location = 0) flat uint instance;
    layout(location = 1) vec2 positionSSPX;
} var;

#include "includes/gui_box_common.glsl"

const vec2 VERTICES[4] = vec2[](
    vec2(0, 1),
    vec2(1, 1),
    vec2(0, 0),
    vec2(1, 0)
);

#define BOX _Boxes[gl_InstanceIndex]
#define VERTEX VERTICES[gl_VertexIndex]

void main() {
    vec2 positionSSPX = VERTEX * BOX.sizePX + BOX.positionSSPX;
    vec4 positionCS = vec4(_Global.matrixSSPXtoCS * vec3(positionSSPX, 1.0), 0.0, 1.0);

    gl_Position = positionCS;
    var.instance = gl_InstanceIndex;
    var.positionSSPX = positionSSPX;
}