#version 460
#extension GL_EXT_ray_tracing : require
#extension GL_GOOGLE_include_directive : enable
#include "raycommon.glsl"

layout(binding = 0, set = 0) uniform accelerationStructureEXT topLevelAS;
layout(binding = 1, set = 0, rgba32f) uniform image2D image;

layout(location = 0) rayPayloadEXT hitPayload prd;

layout(binding = 0, set = 1) uniform CameraProperties
{
  mat4 view;
  mat4 proj;
  mat4 viewInverse;
  mat4 projInverse;
}
cam;

layout(push_constant) uniform Constants
{
  vec4  clearColor;
  vec3  lightPosition;
  float lightIntensity;
  int   lightType;
  int   maxDepth;
}
pushC;

void main()
{
  const vec2 pixelCenter = vec2(gl_LaunchIDEXT.xy) + vec2(0.5);
  const vec2 inUV        = pixelCenter / vec2(gl_LaunchSizeEXT.xy);
  vec2       d           = inUV * 2.0 - 1.0;

  vec4 origin    = cam.viewInverse * vec4(0, 0, 0, 1);
  vec4 target    = cam.projInverse * vec4(d.x, d.y, 1, 1);
  vec4 direction = cam.viewInverse * vec4(normalize(target.xyz), 0);

  uint  rayFlags = gl_RayFlagsOpaqueEXT;
  float tMin     = 0.001;
  float tMax     = 10000.0;

  prd.depth       = 0;
  prd.hitValue    = vec3(0);
  prd.attenuation = vec3(1.f, 1.f, 1.f);
  prd.done        = 1;
  prd.rayOrigin   = origin.xyz;
  prd.rayDir      = direction.xyz;

  vec3 hitValue = vec3(0);
  for(;;)
  {
    traceRayEXT(topLevelAS,     // acceleration structure
                rayFlags,       // rayFlags
                0xFF,           // cullMask
                0,              // sbtRecordOffset
                0,              // sbtRecordStride
                0,              // missIndex
                origin.xyz,     // ray origin
                tMin,           // ray min range
                direction.xyz,  // ray direction
                tMax,           // ray max range
                0               // payload (location = 0)
    );
    hitValue += prd.hitValue * prd.attenuation;

    prd.depth++;
    if(prd.done == 1 || prd.depth >= pushC.maxDepth)
      break;

    origin.xyz    = prd.rayOrigin;
    direction.xyz = prd.rayDir;
    prd.done      = 1;  // Will stop if a reflective material isn't hit
  }

  imageStore(image, ivec2(gl_LaunchIDEXT.xy), vec4(hitValue, 1.0));
}