#version 450

// Instance attributes
layout(location = 0) in vec4 in_rect;   // x, y, width, height
layout(location = 1) in vec4 in_color;  // r, g, b, a

layout(location = 1) out vec4 out_color;
layout(location = 2) out vec2 out_uv;

layout(set = 1, binding = 0) uniform PushConstants {
    vec2 windowSize;
} pc;

void main() {
    vec2 rectPos = in_rect.xy;
    vec2 rectSize = in_rect.zw;

    vec2 cornerOffset = vec2(
        float(gl_VertexIndex & 1),
        float((gl_VertexIndex >> 1) & 1)
    );

    vec2 pixelPos = rectPos + (cornerOffset * rectSize);
    vec2 ndc = (pixelPos / pc.windowSize) * 2.0 - 1.0;
    ndc.y = -ndc.y;
    gl_Position = vec4(ndc, 0.0, 1.0);

    out_color = in_color;
    out_uv = cornerOffset;
}