//SPDX-License-Identifier: LGPL-3.0-only
//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

#version 460
#extension GL_EXT_ray_tracing : enable
#extension GL_EXT_shader_image_load_formatted : enable
#extension GL_EXT_shader_explicit_arithmetic_types_int16 : enable
#extension GL_EXT_descriptor_heap : enable
#extension GL_EXT_nonuniform_qualifier : enable

layout(constant_id = 0) const uint16_t bufferStart = 0us;
layout(descriptor_heap) uniform accelerationStructureEXT topLevelAS[];
layout(descriptor_heap) uniform writeonly image2D image[];

layout(location = 0) rayPayloadEXT vec3 hitValue;

void main() {
    uvec2 pixel = gl_LaunchIDEXT.xy;
    uvec2 resolution = gl_LaunchSizeEXT.xy;
    vec2 ndc = (vec2(pixel) + 0.5) / vec2(resolution) * 2.0 - 1.0;

    // Same pinhole camera as examples/VulkanTriangle, facing +Z.
    vec3 origin = vec3(0.0, 0.0, -300.0);
    float aspect = float(resolution.x) / float(resolution.y);
    float tanHalfFov = tan(radians(60.0) * 0.5);
    vec3 direction = normalize(vec3(ndc.x * aspect * tanHalfFov, -ndc.y * tanHalfFov, 1.0));

    traceRayEXT(topLevelAS[bufferStart], gl_RayFlagsNoneEXT, 0xff, 0, 0, 0,
                origin, 0.001, direction, 10000.0, 0);
    imageStore(image[0], ivec2(pixel), vec4(hitValue, 1.0));
}