sec

На русском

Format: SEC

Description

Map chunk (section)

Structure

File contain one header:

struct header
{
    uint magic; // 74 F7 4B CF

    byte water;
};

After header lay data arrays:

struct vertex
{
    byte x_offset;
    byte y_offset;
    ushort altitude; // z coord

    uint packed_normal;
};

struct vertex land_vertex_array[33][33];

If water != 0 there are additional vertex table:

struct vertex water_vertex_array[33][33];

After that lay texture information:

ushort land_textures[16][16];

If water != 0 there are additional textures table:

ushort water_textures[16][16];

After that if water != 0:

uint water_visible[16][16]; // 1 if visible

Additional information

Normal unpacking (10 bits for z, 11 for x and y):

uint packed_normal;

float x = ((float)((packed_normal >> 11) & 0x7FF) - 1000.0f) / 1000.0f;
float y = ((float)(packed_normal & 0x7FF) - 1000.0f) / 1000.0f;
float z = (float)(packed_normal >> 22) / 1000.0f;