I am making a level editor that needs to output a custom map file for use with source code that I will write for a graphics library.
My question is: What do I need to bear in mind when deciding how to structure a custom file type? Also how can I encode a standard bitmap image into my file (the tile set) so that it can all be contained in a single file rather two files; the map file and tile set (.bmp file).
Thanks.
First you need to design your file layer, you need fixed size data to determine how to decode your variable data, for example, the first four bytes you read could tell how many tiles there are, the next 4 bytes could tell how many map files there are, after that you for example have the first file, you have to define your file information, eg which file and how many bytes it is, then you know how many bytes you're away from the next file entry, etc...
You can also use structures and overload the ofstream operators << and >> for it to create your own filetype, I did this myself when creating a replay system for Need For Speed Underground 2.
struct Point4D { float x, y, z, w; };
struct Point3D { float x, y, z; };
struct Point2D { float x, y; };
struct QuatRot
{
Point4D Front;//frontvector
Point4D Right;//rightvector
Point4D Up;//upvector
};
#define NFS_MAX_VEHICLES (14)//seriously just 14.. (including the player)
struct VehicleInfo
{
//type name array offset
float unknown_01 [8]; //0x0
Point3D Pos; //0x20
float unknown_02; //0x2C
QuatRot Rotation; //0x30
Point3D unknown_03; //0x60
float unknown_04; //0x6C
Point3D Velocity; //0x70
float unknown_05; //0x7C
Point3D TurnSpeed; //0x80
float unknown_06; //0x8C
float SpeedAndBrakeAccelerator; //0x90
float unknown_07 [3]; //0x94
Point3D unknown_08; //0xA0
float unknown_09; //0xAC
Point4D unknown_10 [5]; //0xB0
float unknown_11 [20]; //0x100
float unknown_12_is_zero_when_accelerating; //0x150
//end of structure...?
};
std::ostream& operator<<(std::ostream& stream, const VehicleInfo &info);
//overload << and >> operators on "VehicleInfo" type
std::ofstream& operator<<(std::ofstream& stream, VehicleInfo &info);
std::ifstream& operator>>(std::ifstream& stream, VehicleInfo &info);
//overload << and >> operators on "FrameInfo" type
std::ofstream& operator<<(std::ofstream& stream, Recorder::FrameInfo &info);
std::ifstream& operator>>(std::ifstream& stream, Recorder::FrameInfo &info);
namespace Recorder
{
struct FrameInfo//1392 bytes / frame | max 167040 bytes @ 120 fps | 9.56 MB / min max
{
std::chrono::high_resolution_clock::duration time;
VehicleInfo Vehicle;
int Nitro;
float RPM;
float TURBO;
int CurrentGear;
KeyManager Keys[256];
};
};
std::ofstream& operator<<(std::ofstream& stream, VehicleInfo &info)
{
stream.write(reinterpret_cast<char*>(&info.unknown_01[0]), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.unknown_01[1]), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.unknown_01[2]), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.unknown_01[3]), sizeof(float));
//...
stream.write(reinterpret_cast<char*>(&info.unknown_11[18]), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.unknown_11[19]), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.unknown_11[20]), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.unknown_12_is_zero_when_accelerating), sizeof(float));
return stream;
}
std::ifstream& operator>>(std::ifstream& stream, VehicleInfo &info)
{
stream.read(reinterpret_cast<char*>(&info.unknown_01[0]), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.unknown_01[1]), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.unknown_01[2]), sizeof(float));
//.....
stream.read(reinterpret_cast<char*>(&info.unknown_11[16]), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.unknown_11[17]), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.unknown_11[18]), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.unknown_11[19]), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.unknown_11[20]), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.unknown_12_is_zero_when_accelerating), sizeof(float));
return stream;
}
std::ofstream& operator<<(std::ofstream& stream, Recorder::FrameInfo &info)
{
stream.write(reinterpret_cast<char*>(&info.time), sizeof(std::chrono::high_resolution_clock::duration));
stream << info.Vehicle;
stream.write(reinterpret_cast<char*>(&info.Nitro), sizeof(int));
stream.write(reinterpret_cast<char*>(&info.RPM), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.CurrentGear), sizeof(int));
stream.write(reinterpret_cast<char*>(&info.TURBO), sizeof(int));
for(int i = 0; i < 256; ++i)
{
stream.write(reinterpret_cast<char*>(&info.Keys[i].Pressed), sizeof(bool));
stream.write(reinterpret_cast<char*>(&info.Keys[i].Released), sizeof(bool));
stream.write(reinterpret_cast<char*>(&info.Keys[i].Down), sizeof(bool));
stream.write(reinterpret_cast<char*>(&info.Keys[i].Up), sizeof(bool));
}
return stream;
}
std::ifstream& operator>>(std::ifstream& stream, Recorder::FrameInfo &info)
{
stream.read(reinterpret_cast<char*>(&info.time), sizeof(std::chrono::high_resolution_clock::duration));
stream >> info.Vehicle;
stream.read(reinterpret_cast<char*>(&info.Nitro), sizeof(int));
stream.read(reinterpret_cast<char*>(&info.RPM), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.CurrentGear), sizeof(int));
stream.read(reinterpret_cast<char*>(&info.TURBO), sizeof(int));
for(int i = 0; i < 256; ++i)
{
stream.read(reinterpret_cast<char*>(&info.Keys[i].Pressed), sizeof(bool));
stream.read(reinterpret_cast<char*>(&info.Keys[i].Released), sizeof(bool));
stream.read(reinterpret_cast<char*>(&info.Keys[i].Down), sizeof(bool));
stream.read(reinterpret_cast<char*>(&info.Keys[i].Up), sizeof(bool));
}
return stream;
}
///
std::stringstream& operator<<(std::stringstream& stream, VehicleInfo &info)
{
stream.write(reinterpret_cast<char*>(&info.unknown_01[0]), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.unknown_01[1]), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.unknown_01[2]), sizeof(float));
//...
stream.write(reinterpret_cast<char*>(&info.unknown_11[19]), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.unknown_11[20]), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.unknown_12_is_zero_when_accelerating), sizeof(float));
return stream;
}
std::stringstream& operator>>(std::stringstream& stream, VehicleInfo &info)
{
stream.read(reinterpret_cast<char*>(&info.unknown_01[0]), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.unknown_01[1]), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.unknown_01[2]), sizeof(float));
//....
stream.read(reinterpret_cast<char*>(&info.unknown_11[20]), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.unknown_12_is_zero_when_accelerating), sizeof(float));
return stream;
}
std::stringstream& operator<<(std::stringstream& stream, Recorder::FrameInfo &info)
{
stream.write(reinterpret_cast<char*>(&info.time), sizeof(std::chrono::high_resolution_clock::duration));
stream << info.Vehicle;
stream.write(reinterpret_cast<char*>(&info.Nitro), sizeof(int));
stream.write(reinterpret_cast<char*>(&info.RPM), sizeof(float));
stream.write(reinterpret_cast<char*>(&info.CurrentGear), sizeof(int));
stream.write(reinterpret_cast<char*>(&info.TURBO), sizeof(int));
for(int i = 0; i < 256; ++i)
{
stream.write(reinterpret_cast<char*>(&info.Keys[i].Pressed), sizeof(bool));
stream.write(reinterpret_cast<char*>(&info.Keys[i].Released), sizeof(bool));
stream.write(reinterpret_cast<char*>(&info.Keys[i].Down), sizeof(bool));
stream.write(reinterpret_cast<char*>(&info.Keys[i].Up), sizeof(bool));
}
return stream;
}
std::stringstream& operator>>(std::stringstream& stream, Recorder::FrameInfo &info)
{
stream.read(reinterpret_cast<char*>(&info.time), sizeof(std::chrono::high_resolution_clock::duration));
stream >> info.Vehicle;
stream.read(reinterpret_cast<char*>(&info.Nitro), sizeof(int));
stream.read(reinterpret_cast<char*>(&info.RPM), sizeof(float));
stream.read(reinterpret_cast<char*>(&info.CurrentGear), sizeof(int));
stream.read(reinterpret_cast<char*>(&info.TURBO), sizeof(int));
for(int i = 0; i < 256; ++i)
{
stream.read(reinterpret_cast<char*>(&info.Keys[i].Pressed), sizeof(bool));
stream.read(reinterpret_cast<char*>(&info.Keys[i].Released), sizeof(bool));
stream.read(reinterpret_cast<char*>(&info.Keys[i].Down), sizeof(bool));
stream.read(reinterpret_cast<char*>(&info.Keys[i].Up), sizeof(bool));
}
return stream;
}