enum                            // block types, order matters!
{
    SOLID = 0,                  // entirely solid cube [only specifies wtex]
    CORNER,                     // half full corner of a wall
    FHF,                        // floor heightfield using neighbour vdelta values
    CHF,                        // idem ceiling
    SPACE,                      // entirely empty cube
    SEMISOLID,                  // generated by mipmapping
    MAXTYPE
};

struct sqr
{
    uchar type;                 // one of the above
    char floor, ceil;           // height, in cubes
    uchar wtex, ftex, ctex;     // wall/floor/ceil texture ids
    uchar r, g, b;              // light value at upper left vertex
    uchar vdelta;               // vertex delta, used for heightfield cubes
    char defer;                 // used in mipmapping, when true this cube is not a perfect mip
    char occluded;              // true when occluded
    uchar utex;                 // upper wall tex id
    uchar tag;                  // used by triggers
};

enum                            // hardcoded texture numbers
{
    DEFAULT_SKY = 0,
    DEFAULT_LIQUID,
    DEFAULT_WALL,
    DEFAULT_FLOOR,
    DEFAULT_CEIL
};

#define MAPVERSION 6            // bump if map format changes, see worldio.cpp

struct header                   // map file format header
{
    char head[4];               // "CUBE"
    int version;                // any >8bit quantity is a little indian
    int headersize;             // sizeof(header)
    int sfactor;                // in bits
    int numents;
    char maptitle[128];
    uchar texlists[3][256];
    int waterlevel;
    int reserved[15];
};

#define SWS(w,x,y,s) (&(w)[(y)*(s)+(x)])
#define SW(w,x,y) SWS(w,x,y,ssize)
#define S(x,y) SW(world,x,y)            // convenient lookup of a lowest mip cube
#define S_SECURE(x, y) ((y)*ssize+(x)<=mipsize ? S(x,y) : NULL) // same as above, but validates coords
#define SMALLEST_FACTOR 6               // determines number of mips there can be
#define DEFAULT_FACTOR 8
#define LARGEST_FACTOR 11               // 10 is already insane
#define SOLID(x) ((x)->type==SOLID)
#define MINBORD 2                       // 2 cubes from the edge of the world are always solid
#define OUTBORD(x,y) ((x)<MINBORD || (y)<MINBORD || (x)>=ssize-MINBORD || (y)>=ssize-MINBORD)

struct block { int x, y, xs, ys; };

// vertex array format
    
struct vertex { float u, v, x, y, z; uchar r, g, b, a; };

