Demo data format definition

[EuanKirkhope]

I noticed in the rosetta stone info that there is no details on the demodata level data.

From my decompile of a TR1 exe that I'm playing with this is the usage of demo data:

LoadLevel()
{
...
  g_demoDataIndex = 0;
  g_pDemoData = (tr_demodata *)GameMalloc(36000,0x1b);  // load 36000 bytes from file, 0x1B is string "Load Demo Buffer"
...
}

// g_pDemoData is referenced in only 3 functions
// GameDemoSetCurrentEntity:00415d03(R)
// GameDemoRunTimer:00415d7e(R),
// LoadLevel:0041b36c(W), 

void GameDemoRunTimer(void)
{
  if (g_demoRunTime < 9000) {
    g_gameInputCmds = g_pDemoData[g_demoDataIndex]; // gets first tr_demodata field
  }
  else {
    g_gameInputCmds = 0xffffffff;
  }
  if (g_gameInputCmds != 0xffffffff) {
    g_demoDataIndex= g_demoDataIndex+ 1;  // moves demodata to the entity camera / position information
  }
  return;
}

void xGameDemoSetCurrentEntity(void)

{
  short height;
  tr1_room_sector *pSector;
  short room;
  tr1_entity *pEnt;
  
  pEnt = g_pCurrentEntity;
  g_pCurrentEntity->x = g_pDemoData[0];
  pEnt->y = g_pDemoData[1];
  pEnt->z = g_pDemoData[2];
  pEnt->rotateY = *(short *)(g_pDemoData + 3);
  pEnt->rotateX = *(short *)(g_pDemoData + 4);
  pEnt->rotateZ = *(short *)(g_pDemoData + 5);
  room = *(short *)(g_pDemoData + 6);

  if (pEnt->Room != room) {
    GameSetEntityItemRoom(g_currentEntityIndex, room);
  }

  pSector = GameClipToRoom(pEnt->x,pEnt->y,pEnt->z,&room);
  height = GameGetHeight(pSector,pEnt->x,pEnt->y,pEnt->z);
  g_pCurrentEntity.height = height;

  g_demoDataIndex = g_demoDataIndex + 7;  // increment demodata index to next flags field for GameDemoRunTimer()

  return;
}

/* structure definition 

struct tr_demodata
    int32_t flags; 
    struct tr_demodata_entitypos
    {
        int32_t x;
        int32_t y;
        int32_t z;
        int16_t rotX;
        int16_t reseverved1; // alignment padding
        int16_t rotY;
        int16_t reseverved2;
        int16_t rotZ;
        int16_t reseverved3;
        int16_t roomId;
        int16_t reseverved4;
    }
}

*/