struct CryEngineDecalInfo {
  SDecalOwnerInfo ownerInfo;
  Vec3 vPos;
  Vec3 vNormal;
  float fSize;
  float fLifeTime;
  float fAngle;
  struct IStatObj * pIStatObj;
  Vec3 vHitDirection;
  float fGrowTime, fGrowTimeAlpha;
  unsigned int nGroupId;
  bool bSkipOverlappingTest;
  bool bAssemble;
  bool bForceEdge;
  bool bForceSingleOwner;
  bool bDeferred;
  uint8 sortPrio;
  char szMaterialName[_MAX_PATH];
  bool preventDecalOnGround;
  const Matrix33* pExplicitRightUpFront;
};

CryEngineDecalInfo.h

bool bAssemble;

Assemble to bigger decals if more than 1 decal is on the same place

bool bDeferred;

bool bForceEdge;

force the decal to the nearest edge of the owner mesh and project it accordingly

bool bForceSingleOwner;

Do not attempt to cast the decal into the environment even if it's large enough

bool bSkipOverlappingTest;

Always spawn decals even if there are a lot of other decals in same place

float fAngle;

Angle of rotation

float fGrowTime;

float fGrowTimeAlpha;

float fLifeTime;

Decal life time (in seconds)

float fSize;

Decal size

unsigned int nGroupId;

Used for multi-component decals

SDecalOwnerInfo ownerInfo;

const Matrix33* pExplicitRightUpFront;

mainly for decal placement support

struct IStatObj * pIStatObj;

Decal geometry

bool preventDecalOnGround;

mainly for decal placement support

uint8 sortPrio;

char szMaterialName[_MAX_PATH];

name of material used for rendering the decal (in favor of szTextureName/nTid and the default decal shader)

Vec3 vHitDirection;

Direction from weapon/player position to decal position (bullet direction)

Vec3 vNormal;

Decal/face normal

Vec3 vPos;

Decal position (world coordinates)

CryEngineDecalInfo();

the constructor fills in some non-obligatory fields; the other fields must be filled in by the client

void GetMemoryUsage(ICrySizer * pSizer) const;