#extension GL_EXT_buffer_reference : require
#extension GL_EXT_nonuniform_qualifier : require

layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in;

layout(set = 0, binding = 2, rgba32f) uniform image2D images[];

struct camera {
    vec4 position;

    vec4 forward;
    vec4 up;
    vec4 right;

    vec4 horizontal;
    vec4 vertical;
    vec4 first_pixel;

    float lens_radius;
    float fov;
    float focus_distance;
    float aspect_ratio;
};

layout(buffer_reference) readonly buffer global_params {
    camera cam;

    uint max_bounce;
    uint min_bounce;
    uint width;
    uint height;

    uint sample_index;
    uint enable_dof;
    uint debug_bvh;
    int downscale_factor;
};

layout(buffer_reference) readonly buffer pass_params {
    uint padding;
};

layout(buffer_reference) readonly buffer draw_params {
    uint output_image_index;
    uint accumulation_image_index;
};

layout(push_constant) uniform registers {
    global_params globals;
    pass_params pass;
    draw_params draw;
} regs;

void main() {
    ivec2 coords = ivec2(gl_GlobalInvocationID.xy) * regs.globals.downscale_factor;

    vec3 color = imageLoad(images[nonuniformEXT(regs.draw.accumulation_image_index)], coords).rgb;
    vec3 out_color = sqrt(color);

    for (uint i = 0; i < regs.globals.downscale_factor; i++) {
        for (uint j = 0; j < regs.globals.downscale_factor; j++) {
            imageStore(images[nonuniformEXT(regs.draw.output_image_index)], coords + ivec2(i, j), vec4(out_color, 1.0));
        }
    }
}