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[Reelya]

Saving (or copying) a struct just directly copies all member variables. This does not include following pointers and saving out dynamic memory. You need to write custom loader/savers if you want to do something like that. The issue is that only the pointers are saved, i.e. the numerical memory addresses. When the struct is loaded, none of that data necessarily exists any more, and the values in the pointers are effectively meaningless.

To save (or copy) a struct/class which uses dynamic memory, you need to write custom load/save code (or a copy-constructor, for copying), e.g. save out the non-pointer parts, then save out the dynamic data. Then, on loading, create the struct, allocate new memory for the dynamic data, then set the pointer correctly for the newly allocated memory.

The example which uses a set-sized char array avoids the problem, because the data is directly embedded in the struct, which is the bit you told it to copy.

[i2amroy]

Just spent almost a half an hour wondering why my pthread implementation for one of my classes wasn't working right... before realizing that I was trying to run it on my Windows desktop instead of my OSX laptop. Swapped the code over and and everything runs perfectly on the first try.
*facepalm*

[itisnotlogical]

Why do people release things and then not document them? More importantly, why do they write half of a rambling, utterly useless wiki and call that "documentation"?

I have no idea how anybody ever released a game using Rain AI. The website is like something from an aborted start-up. If anybody can find the "world-class support" they promise on the website, I'll eat multiple hats.

[Reelya]

It's a completely free product. You get what you pay for, and nobody is paying these guys to write documentation.

[flabort]

On a scale of 1 to 10, how hard is it to learn Lua?

[LoSboccacc]

On a scale of 1 to 10, how hard is it to learn Lua?

if you know another language, I'd say a 4 - the hardest part is that there are no conventional data structures but the dictionary which kind of work like your average map but not quite and only support certain keys.

[Putnam]

Huh? Lua has a table, not a dictionary, and it's basically a combination between an array and a hash map which supports all keys (string, integers, tables and userdata are all valid keys).

[flabort]

Crosspost, as to the reason I want to learn Lua properly.

One reason I'm excited to see Sean doing some modding is because I've started some work on an ambitious project of my own.

So tell me, besides the fact that I haven't added image links or defined the items that these ores produce, is there anything blatantly wrong with this code?

Spoiler (click to show/hide)

Code: [Select]

data:extend(
{
{
type = "resource",
name = "adamite-ore",
icon = --NOTE: FIX THIS LINE BEFORE DOING ANYTHING ELSE!!!!!
flags = {"placeable-neutral"},
order = "a-b-f",
infinite = true,
minimum = 500,
normal = 5000,
minable =
{
hardness = 1.5,
mining_particle = --FIGURE THIS OUT TOO
mining_time = 2,
result = "adamite-ore"
},
collision_box = {{ -0.1, -0.1}, {0.1, 0.1}},
selection_box = {{ -0.5, -0.5}, {0.5, 0.5}},
autoplace =
{
control = "adamite-ore"
sharpness = 1
richness_multiplier = 10000,
richness_base = 500
size_control_multiplier = 0.06,
peaks =
{ --I HAVE NO CLUE WHAT'S GOING ON HERE
{
influence = 0.2,
starting_area_weight_optimal = 0,
starting_area_weight_range = 0,
starting_area_weight_max_range = 2,
},
{
influence = -0.3,
richness_influence = -0.2,
noise_layer = "stone",
noise_octaves_difference = -3,
noise_persistence = 0.2,
},
{
influence = -0.3,
richness_influence = -0.2,
noise_layer = "coal",
noise_octaves_difference = -3,
noise_persistence = 0.2,
},
{
influence = 0.5
richness_influence = -0.5
noise_layer = "iron-ore",
noise_octaves_difference = -2.3,
noise_persistence = 0.2,
}
}
}, --This ends Autoplace, right?
stage_counts = {0}
stages =
{
sheet =
{
filename = --AAAAAAAH
priority = "extra-high",
width = 38,
height = 38,
frame_count = 4,
variation_count = 1
}
},
map_color = {r=0.2, g=0.1, b=0.56}
},

{
type = "resource",
name = "crystal",
icon = --AAAAAAAADD THIS TOO!!!
flags = {"placeable-neutral"},
order = "a-b-g",
minable =
{
hardness = 0.7,
mining_particle = --FIGURE THIS OUT SOON BOI
mining_time = 2,
result =
{
{type = "item", name = "crystal-shard", amount = 1, probability = 0.7},
{type = "item", name = "crystal-shard", amount = 4, probability = 0.1},
{type = "item", name = "crystal-whole", amount = 1, probability = 0.2}
}
},
collision_box = {{ -0.1, -0.1}, {0.1, 0.1}},
selection_box = {{ -0.5, -0.5}, {0.5, 0.5}},
autoplace =
{
control = "crystal",
sharpness = 1,
max_probability = 0.02,
richness_multiplier = 18000,
richness_base = 6000,
size_control_multiplier = 0.08,
peaks =
{
{influence = 0.1},
{
influence = 0.2,
starting_area_weight_optimal = 1,
starting_area_weight_range = 1,
starting_area_weight_max_range = 3,
}
}
},
stage_counts = {0}
stages =
{
sheet =
{
filename = --AAAAAAAH
priority = "extra-high",
width = 38,
height = 38,
frame_count = 4,
variation_count = 1
}
}
map_color = {r=0.9, g=0.45, b=0.45},
}
})

[Putnam]

Code: [Select]

control = "adamite-ore"
sharpness = 1
richness_base = 500
stage_counts = {0}
if these lines don't have commas it'll error

[Elephant Parade]

Still trying to learn to program. I've stuck with Python, but I'm not sure how good it is for making games; if it isn't great for that kind of thing, can someone recommend me a second language--one that is good for making games?

If it matters, I want to make a Mystery Dungeon-style game; something in the vein of Pokemon Mystery Dungeon, with sprites and randomly-generated floors and stuff.

[Willfor]

Python's ability to be good for any given thing is entirely dependent on what you're trying to do with it. There are some speed issues that make certain tasks more difficult, but as long as you use the tools you're playing with in Python right, it's going to be fine enough to make a turn based game like a mystery dungeon work.

The issue you're going to come across is in your distribution; Yes, you can make an .exe but I've found the process is a bit painful. I mean, it's the same way in so many other languages, and it's not as painful as trying to figure out C or C++, but there you go.

[flabort]

Code: [Select]

control = "adamite-ore"
sharpness = 1
richness_base = 500
stage_counts = {0}
if these lines don't have commas it'll error

Thanks.

[Spehss _]

So I have a bug in this program for my college assignment. Program takes input/output from a binary file of struct data, and uses a menu interface to allow the user to add to the file, make changes to the file, or display either one specific struct or all of the structs in the file.

The bug consists of the program writing a duplicate struct of the last user input to the file. So if the user enters input for "Item 1" then goes to display all records in the file, "Item 1" is displayed twice. Additionally, my checkSize() function recognizes that this is actual data in the file, it's not just an issue with displaying data. Attempting to access this duplicate structure specifically with the function to display a specific struct results in displaying a bunch of garbage data. I think the duplicate is the result of the input/output buffer sending a bunch of garbage data when the file is closed and the buffer is flushed. But I can't be certain if that's what's causing it, and I can't find where the code is that's causing the bug.

Spoiler: c++ code (click to show/hide)

Code: [Select]

#include <iostream>
#include <iomanip>
#include <fstream>
#include <cstring>

using namespace std;

const int DESCR_LENGTH=101, DATE_LENGTH=31;

struct Item{
char descr[DESCR_LENGTH];
int quantity;
double wholesale, retail;
char date[DATE_LENGTH];
};

long checkSize(const char filename[]) //returns the number of Item structures contained in the file
{
fstream file(filename, ios::in|ios::binary);
Item dummy;
long accumulator=0;
while(!file.eof())
{
file.read(reinterpret_cast<char*>(&dummy),sizeof(dummy));
accumulator+=sizeof(dummy);
}
file.close();
return accumulator/sizeof(dummy);
}

void getInput(Item &item)
{
string input="";
cout<<"\n-----------------------\n";
//get description
cout<<"Enter a description of this item: ";
cin.ignore(); //ignores whitespace in stream from earlier cin use from menu()
getline(cin, input);
strcpy(item.descr, input.c_str());
// cout<<"\n"<<item.descr<<endl; //debug

//get quantity
cout<<"Enter item quantity: ";
cin>>item.quantity;
// cout<<"\nYou entered: "<<item.quantity<<endl; //debug

//get wholesale and retail prices
cout<<"Enter wholesale price of this item: ";
cin.ignore(); //ignore whitespace from prior input
cin>>item.wholesale;
// cout<<"\nYou entered: "<<item.wholesale<<endl; //debug

cout<<"Enter retail price of this item: ";
cin.ignore(); //ignore whitespace from prior input
cin>>item.retail;
// cout<<"\nYou entered: "<<item.retail<<endl; //debug

//get date
cout<<"Enter the current date: ";
cin.ignore(); //ignore any whitespace from previous input
getline(cin,input);
strcpy(item.date, input.c_str());
// cout<<"\nDate added: "<<item.date<<endl; //debug
}

void addRecords(const char filename[])
{
Item in;
getInput(in);
fstream file(filename, ios::out|ios::app|ios::binary);
file.write(reinterpret_cast<char*>(&in),sizeof(in));
file.close();
cout<<"\nRecord written to file."<<endl;
}

void displayRecords(const char filename[])
{
Item out;
fstream file(filename, ios::in|ios::binary);
do
{
file.read(reinterpret_cast<char *>(&out),sizeof(out));
cout<<setprecision(2)<<fixed
<<"Description: "<<out.descr
<<"\nQuantity: "<<out.quantity
<<"\nWholesale Price: $"<<out.wholesale
<<"\nRetail Price: $"<<out.retail
<<"\nDate added to file: "<<out.date
<<"\n"<<endl;
}while(!file.eof());
file.close();
}

void displayRecords(const char filename[], int slot, long recordNum) //reads a specific record using slot to determine what bit the record starts at
{
Item out;
fstream file(filename, ios::in|ios::binary);
if(slot<=recordNum&&slot>0) //errorchecking if user input is a valid choice
{
long num=(slot-1)*sizeof(out);

file.seekg(num, ios::beg);
file.read(reinterpret_cast<char *>(&out), sizeof(out));

cout<<setprecision(2)<<fixed
<<"Description: "<<out.descr
<<"\nQuantity: "<<out.quantity
<<"\nWholesale Price: $"<<out.wholesale
<<"\nRetail Price: $"<<out.retail
<<"\nDate added to file: "<<out.date
<<"\n"<<endl;
}
else
cout<<"\nError. Invalid input. Record #"<<slot<<" does not exist."<<endl;
file.close();
}

void menu(const char filename[])
{
char input;
int num=0; //used for input if user specifies choosing a specific file
long recordNum=checkSize(filename);
do
{
cout<<"---------------------------------\n"
<<"What would you like to do with "<<filename<<"?"
<<"\nA) Add new records to the file."
<<"\nB) Display one record currently on file."
<<"\nC) Change any record currently on file."
<<"\nD) Display all records currently on file."
<<"\nQ) Quit Program."
<<"\n>>";
cin>>input;
recordNum=checkSize(filename); //updates value contained in recordNum to reflect changes done to file
switch(input)
{
case 'a':
case 'A': addRecords(filename); break;

case 'b':
case 'B': cout<<"\nRecords contained in "<<filename<<" : "<<recordNum
  <<"\nEnter a number from 1 to "<<recordNum<<" to view the corresponding record.\n>>";
  cin>>num;
  displayRecords(filename, num, recordNum); break;

case 'c':
case 'C': cout<<"\nRecords contained in "<<filename<<" : "<<recordNum
  <<"\nEnter a number from 1 to "<<recordNum<<" to change the corresponding record.\n>>";
  cin>>num;
  //changeRecords(filename, num); //need to add this
  break;

case 'd':
case 'D': displayRecords(filename); break;

case 'q':
case 'Q':break;

default: cout<<"\nInvalid menu choice."<<endl;
}
}while(input!='q'&&input!='Q');
}

int main()
{
const char FILENAME[]={"inventory.dat"};
fstream file(FILENAME, ios::out|ios::in|ios::binary);
if(!file)
{
//if file doesn't exist, an empty file is created by opening a file in out mode
cout<<"Error. "<<FILENAME<<" does not exist. Created a blank file named "<<FILENAME<<endl;
file.open(FILENAME,ios::out|ios::binary);
file.close();
}
file.close();

menu(FILENAME);

return 0;
}


[breadman]

Still trying to learn to program. I've stuck with Python, but I'm not sure how good it is for making games;

PyWeek has many examples of simple games that were developed in Python within one week each.  It also has a list of tips and resources to help in such an endeavor.  One of the best ways to start may be with PyGame Zero.

But yes, distributing a Python game can still be harder than it really should be, particularly to Windows users.

[itisnotlogical]

Distributing a Python program means (unless your audience can safely be assumed to have Python, ie Linux) distributing Python, and there aren't a lot of tools that make that very easy unless you were embedding Python in C or Java or something. And at that point, why not just write your game/app in those languages instead?

I most commonly see Python used as an embedded scripting language, kind of like Lua, so that people can add their own functionality to programs like Blender.