#define ENABLE_PRINT 0

#define TERMINATE -40
#define IGNORE      0
#define ACCEPT     40
#define OPAQUE     41

#define LEAF_DONE     90
#define LEAF_INST     91
#define LEAF_TRIS     92
#define LEAF_CUSTOM   93

#define RAYGEN     190
#define INTERSECT  290
#define ANYHIT     390
#define CLOSESTHIT 490
#define MISS       590
#define TRACERAY   999


#ifndef HLSL
typedef unsigned uint;

#define HIT_KIND_TRIANGLE_FRONT_FACE    0xFE
#define HIT_KIND_TRIANGLE_BACK_FACE     0xFF

#define RAY_FLAG_NONE                         0x00
#define RAY_FLAG_FORCE_OPAQUE                 0x01
#define RAY_FLAG_FORCE_NON_OPAQUE             0x02
#define RAY_FLAG_TERMINATE_ON_FIRST_HIT       0x04
#define RAY_FLAG_SKIP_CLOSEST_HIT_SHADER      0x08
#define RAY_FLAG_CULL_BACK_FACING_TRIANGLES   0x10
#define RAY_FLAG_CULL_FRONT_FACING_TRIANGLES  0x20
#define RAY_FLAG_CULL_OPAQUE                  0x40
#define RAY_FLAG_CULL_NON_OPAQUE              0x80

#define INSTANCE_FLAG_NONE                              0x0
#define INSTANCE_FLAG_TRIANGLE_CULL_DISABLE             0x1
#define INSTANCE_FLAG_TRIANGLE_FRONT_COUNTERCLOCKWISE   0x2
#define INSTANCE_FLAG_FORCE_OPAQUE                      0x4
#define INSTANCE_FLAG_FORCE_NON_OPAQUE                  0x8

#endif

static int pack(int primIdx, int geomIdx, bool opaque)
{
  return
      (opaque ? 0x80000000 : 0)
    | (geomIdx << 16)
    | (primIdx);
}

#ifdef HLSL
static void unpack(int val, out uint primIdx, out uint geomIdx, out bool opaque)
{
  opaque = val & 0x80000000;
  geomIdx = (val >> 16) & 0xFFFF;
  primIdx = val & 0xFFFF;
}
#endif

static bool isOpaque( bool geomOpaque, uint instanceFlags, uint rayFlags )
{
  bool opaque = geomOpaque;

  if( instanceFlags & INSTANCE_FLAG_FORCE_OPAQUE )
    opaque = true;
  else if( instanceFlags & INSTANCE_FLAG_FORCE_NON_OPAQUE ) 
    opaque = false;

  if( rayFlags & RAY_FLAG_FORCE_OPAQUE )
    opaque = true;
  else if( rayFlags & RAY_FLAG_FORCE_NON_OPAQUE )
    opaque = false;

  return opaque;
}

static float computeCullFaceDir(uint instanceFlags, uint rayFlags)
{
  float cullFaceDir = 0;
  if( rayFlags & RAY_FLAG_CULL_FRONT_FACING_TRIANGLES )
    cullFaceDir = 1;
  else if( rayFlags & RAY_FLAG_CULL_BACK_FACING_TRIANGLES )
    cullFaceDir = -1;
  if( instanceFlags & INSTANCE_FLAG_TRIANGLE_CULL_DISABLE )
    cullFaceDir = 0;

  return cullFaceDir;
}

static bool cull(bool opaque, uint rayFlags)
{
  return (opaque && (rayFlags & RAY_FLAG_CULL_OPAQUE)) || (!opaque && (rayFlags & RAY_FLAG_CULL_NON_OPAQUE));
}